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Stainless Steel Supports Innovative and Engaging New Face for the Australian Museum

27 October 2016

The Australian Museum's 2015 facelift saw its new entrance made with a contemporary glass curtain wall feature supported by stainless steel.

The design brief for the architecturally stunning entrance hall feature was a structure that conveyed the image of a modern and transparent institution. Designers Neeson Murcutt Architects and Joseph Grech Architects drew inspiration from the museum’s collection of gemstones for the new façade, resulting in a double-glazed window set against coloured glass panes.

ASSDA Member SGM Fabrication & Construction fabricated the stainless steel frames to support the glass facade as part of the museum’s redevelopment plan. This transformation saw Australia’s oldest museum swing the orientation of its entrance from College Street to William Street.

Fifteen stainless steel framed glass panels stand 8.5m high by 1.6m wide to form a dramatic vertically pleated structure that runs parallel to and complements the existing sandstone wall. Behind the glass façade are 48 diamond-shaped coloured glass panes positioned to take advantage of the northern sun, diffusing and refracting the light to create a welcoming ambience into the museum.

Around 30 tonnes of specialty glass was imported from Luxembourg for the façade. Seven tonnes of 316L stainless steel was used for the frames, including rectangular hollow sections (RHS) supplied by ASSDA Sponsor Midway Metals and 8mm plate supplied and laser cut by ASSDA Sponsor Vulcan Stainless.

SGM Fabrication & Construction’s Managing Director Scott McHugh said welding the stainless steel frames was challenging due to the length and material, and all stainless steel plate had to be individually laser cut by Vulcan Stainless prior to being pressed. ‘Straightness was a big consideration due to the frames holding 30mm thick glass in place. The frames had to be straight and true to within 3mm over the entire length (0.4% tolerance) to support the double-glazed glass.’

The stainless steel frames were pickled and passivated by ASSDA Member Australian Pickling & Passivation Service (APAPS) to remove any heat-affected areas from the laser cuttings and to ensure there was no iron contamination from the pressing.

The frames were specified in stainless steel for its strength, visual appeal and similarity of low maintenance regimes with glass. It was installed by Kane Constructions and the entrance hall was officially opened in September 2015.

The museum’s grand entrance feature is a modern addition to the historically and culturally significant building, certain to maintain its visual appeal for decades to come.

This article is featured in Australian Stainless Issue 57 (Spring 2016).

Images courtesy of Kane Constructions.

Impressive Stainless Steel Ribbon Graces New Brisbane Food Gallery

27 October 2016

Stainless steel has brought life to a unique food precinct located in a recently opened premium office tower in Brisbane City's Golden Triangle.

Developed and constructed by Grocon, 480 Queen Street’s sustainable and eclectic design boasts a 6 Star Green Star and a 5 Star NABERS rating. The building’s food gallery, otherwise known as Room 480, is located on level 2 and capitalises on the stunning views of Brisbane River and Story Bridge to deliver a restaurant style experience and retreat for diners.

Complementing this space is a suspended stainless steel sculpture, designed by local architecture and interior design practice Arkhefield. Inspired by water flowing around rocks, the ‘stainless steel ribbon’ delicately hangs from the ceiling and weaves over the landscape of the room.

Grade 304 stainless steel was specified for the ribbon feature, using 100m of 0.9 x 600mm coil supplied by ASSDA Sponsor Dalsteel Metals. The 1 tonne of coil was supplied in a Bright Annealed (BA) finish and polyethylene coating on both sides for protection, with one side brighter than the other to fulfill the architectural effect and design requirements.

Arkhefield wanted the ribbon feature to be highly reflective on one side, with a brushed appearance on the other. As it curves and wraps through the space, the bright and flat sides of the stainless steel ribbon interact to reflect the surrounding colours and light, allowing movement and distortion throughout. Stainless steel proved the only material able to achieve this aesthetically appealing finish, whilst providing a high-quality, durable and lightweight structure.

The stainless steel ribbon spans 35m x 6m across Room 480’s ceiling and was installed by ASSDA Member and Accredited Fabricator Stainless Aesthetics.

Stainless Aesthetics Director Mike Mooney said the installation of the entire 1 tonne of stainless steel coil as a continuous ribbon was one of the more challenging aspects of the project. This was successfully achieved using their custom designed and fabricated turntable, which housed the coil and allowed it to unwind safely 3.5m above floor level, while protecting the ribbon’s surface finish.

The installation of the stainless steel ribbon around the light fixtures emphasised the visual appeal of the sculpture and its surface qualities. It is suspended using 3.2mm wire support cables and fixings in grade 316 stainless steel supplied by ASSDA Member Anzor Fasteners.

The stainless steel ribbon is an impressive and visually dynamic integrated element of Room 480, adding colour and movement to a traditionally formal space. In addition, the sculpture provides a level of intimacy to the space that could not be achieved with a standard flat suspended ceiling, providing a pleasant ambience for patrons to dine and relax.

This article is featured in Australian Stainless Issue 57 (Spring 2016).

Images courtesy of Stainless Aesthetics.

Stainless Steel Transforms Meat Processing Plant

27 October 2016

Over 17 tonnes of stainless steel has been used for the upgrade of a premier meat processing plant to support the growing local and global demands of Australian red meat supply.

The Australian Lamb Company (ALC) currently exports lamb to more than 60 countries worldwide, and recently secured a 10-year contract to process lamb for Coles supermarkets in eastern Australia.

ALC’s multi-million dollar investment to support demand and increase production capacity included the expansion and upgrade of its meat processing operation in Colac, Victoria.

ASSDA Member and Accredited Fabricator Stainless Steel Associated Fabricators (SSAF) Australia was engaged to design, manufacture and install 65 box conveyors spanning 400m, three access walkovers and 30 production tables for the plant’s re-engineered automated boning room.

The conveyor system was designed by SSAF Australia with input from the ALC’s production team to achieve optimum process flow. The main criterion for the mechanical design was excellent product transfer, mechanical reliability and optimal hygiene through easy cleaning of the conveyor’s belt and frame.

The box conveyors are a semi-modular design using the latest SEW-EURODRIVE MOVIGEAR® SERVO motors and gearboxes. Compared with conventional motors and gearboxes, SSAF Australia’s Managing Director Chris Stacey said these systems are significantly more efficient in reducing power usage and allowing a wider speed range without loss in torque.

Grade 304 stainless steel with a 2B finish was specified and used for the upgrade, supplied by ASSDA Sponsors Atlas SteelsMidway Metals and Vulcan Stainless.

Grade 304 stainless steel is a standard requirement in the food industry where acid and salt are not present in the production process. With rigorous standards in food safety and hygiene to adhere to, the boning room must be washed down daily and to this end, the conveyors incorporate CIP (clean in place) systems.

Stacey said that grade 304 2B stainless steel with a PVC protective coating is the material of choice for their food grade equipment. ‘By taking care during manufacture and polishing welds to 320G, 2B is superior to a No 4 or bead blasted finish. The smoother grain structure is much better than No 4 in inhibiting the growth of microorganisms and is easier to clean. Our equipment is regularly swabbed for surface cleanliness and this is critical to our customers’ Quality Assurance (QA) requirements.’

With the full scope of works completed within a 6-month timeframe in early September 2016, the increased capacity of ALC’s Colac operation has delivered significant benefits for the Australian lamb industry and a boost in the Victorian economy.

This article is featured in Australian Stainless Issue 57 (Spring 2016).

Images courtesy of SSAF Australia.

Running Water

27 October 2016

Water authorities tackle water shortages with stainless steel.

Water is a fundamental human need. It is central to our lives, from what we drink, to what we use in washing ourselves, our clothes and a multitude of other uses. Safe, clean and palatable water comes at a price though, and when leaks occur in distribution systems, additional costs are incurred as even more water must be found and treated. Security of water supply is a prerequisite for sustainable growth and dealing with leakage is a universal challenge. To combat the scourge of leaks, a number of water distribution authorities across the world have implemented affordable solutions utilising stainless steel, which not only saves money, but water, a precious resource.

Tokyo, Japan

Prior to the 1980’s, water shortages in Tokyo were chronic and rationing was occasionally required. When the city’s water provider, the Tokyo Metropolitan Government Waterworks Bureau (TMGWB), analysed leakage repairs, they determined that 97% were on the distribution pipes of 50mm diameter or less. In Tokyo, there are more than two million such connections that take the water from the mains to internal systems in buildings. Historically, lead pipe was the preferred material for distribution lines because it is soft, malleable and easy to work with, especially for the last few metres from the mains to buildings. Once lead pipe is in the ground, however, various forces can act on it. Vibrations from traffic and construction work as well as subsidence and earthquakes can cause the soft lead pipes to deform, become detached or even break.

In 1980, TMGWB started to actively replace all service connections with grade 316 (UNS S31600) stainless steel pipe. In 1998 corrugated grade 316 (S31600) stainless steel pipe was introduced for distribution lines that take water from the mains to final destinations in homes, offices and industrial plants. The pipe is corrugated at regular intervals to allow for it to be bent during installation, to accommodate changes in direction and the avoidance of obstacles without additional joints. It also allows for movement of the pipe during earth movement and seismic events. By supplying a single length of corrugated stainless steel pipe, the number of pipe joints was greatly reduced. In switching to stainless steel pipe, the reliability of the water supply has increased and the leakage rate has been reduced by 86% from 15.4% (1980) to 2.2% (2013). To put this into context, since 1994 Tokyo has reduced annual water leakage by nearly 142 million cubic metres - the equivalent of 155 Olympic-size swimming pools per day, with savings in excess of US$200 million per year. Also, annual leak repairs have decreased from 60,000 (1983) to 10,000 (2013). Due to the corrosion resistance of stainless steel, TMGWB expects service life in excess of 100 years.

Graph below: Correlation between repair cases, leakage rates and installation of stainless steel pipes in Tokyo.
Courtesy of the Bureau of Water Works, Tokyo Metropolitan Government.

 

Taipei, Taiwan

In 2002, a severe drought brought intermittent water supplies to the Taiwanese capital over a 49-day period. Of the 450 metering areas in the city, 40% were losing half of their water or more before it reached consumers.

Analysis of repair cases showed that while polybutylene pipe made up only 3% of the length of the system, it accounted for 28% of all leaks. Approximately 90% of all problems occurred in plastic pipes, with the vast majority (83%) caused by cracking.

In 2003, the Taipei Water Department began a similar program to Tokyo, replacing distribution lines with corrugated grade 316L (S31603) stainless steel pipe. Although the ongoing program has so far only replaced 35% of the lines, the result has been a reduction in water loss from 27% (2003) to 17% (2014). This adds up to an annual saving of 146 million cubic metres of water, the equivalent of 160 Olympic-size swimming pools per day.

In 2014, a drought occurred with even less rainfall than the 2002 event which precipitated the pipe replacement program. However this time, the improvement in leakage rates achieved since 2003 meant there was no interruption to the water supply.

The 2002 drought in Taipei caused severe water shortages.
Image courtesy of the Taipei Water Department.

 

Western Cape, South Africa

South Africa is by nature a semi-arid country; its annual rainfall is only half the global average. It has a population of 55 million and is facing freshwater scarcity. It is estimated that at least 37% of its clean drinkable water is lost due to leakage from old and unreliable infrastructure.

The Groot Drakenstein Valley is the cradle of the South African deciduous fruit and wine industries. Water is supplied to over 800 farms including 50 vineyards. Here, there are numerous examples of carbon steel and cast iron pipes that have failed in many areas after just one year due to the very aggressive acidic soils and high water table. “We started a project in 1992 in the Drakenstein Municipality to replace existing piping with stainless steel,” explains André Kowalewski, Senior Engineer - Water Services, Drakenstein Municipality. “We have reduced water loss to around 13% in comparison to the 37% national average. Ten years back only the Drakenstein Municipality used stainless steel. Now 80% of the Western Cape municipalities do.”

André and his team plan for a life expectancy in excess of 50 years. Stainless steel used in Drakenstein is primarily grade 316 and in some cases grade 304 (S30400) in visible locations. Projects are currently focussed around pumping, purification, storage, pipelines and sewage. One such project is a 500 mega-litre/day delivery system completely in grade 316 stainless steel.

Stainless steel pipe in the Western Cape resists aggressive acidic soil conditions.
Images courtesy of Johan Van Zyl.

   

 

Investing in the future

The experience of Tokyo, Taipei and the Western Cape gives water authorities the confidence to specify stainless steel for piping systems. While the initial cost compared to competing materials may be higher, stainless steel has been shown to be a good investment over its long life, paying back each year in reduced maintenance and cost per litre processed.

This article was originally printed in Nickel Magazine (August 2016, Vol. 31, No.2), published by ASSDA Sponsor Nickel Institute.

This article is featured in Australian Stainless Issue 57 (Spring 2016).

Banner image: Corrugated pipe installation. Image courtesy of Tokyo Suido Services/Showarasekan.

Stainless Steel Design Innovation

26 May 2016

Brisbane’s iconic Story Bridge is sporting increased safety measures with the application of innovative stainless steel products and laser-fusion technology.

 The 76-year old heritage-listed cantilever bridge now incorporates three-metre tall, stainless steel safety barriers on its pedestrian walkways, as a result of an outstanding collaboration between multiple project stakeholders. Completed in December 2015, the $8.4 million project was led by design and construct head contractor, Freyssinet.

The design brief was to develop an anti-climb structure that was both functional and aesthetically appealing, whilst ensuring the heritage values of the bridge were maintained.

This presented a number of engineering challenges, including the affixation of the barrier structure to the existing heritage-listed bridge without permanent methods of attachment, such as welding or other damaging techniques, whilst addressing the weight and wind load tolerances, ambient vibrations and noise potential.

Visually, there was also a key design requirement to ensure pedestrian views of the river, Brisbane city and surrounds, and of the Story Bridge itself, was preserved.

The initial reference design was specified in stainless steel (with an option for painted carbon steel) and required the fabrication of heavy box sections for over 1000 posts to support a tamper-resistant, horizontal balustrade cable system. The outrigging was specified in carbon steel, with isolation joints to support the upright posts. However, aesthetically, this design created a clutter of vertical elements.

Freyssinet developed an alternative design concept employing Carl Stahl X-TEND® stainless steel mesh, and engaged ASSDA Member Ronstan Tensile Architecture to assist in the design rationalisation. Ronstan Tensile Architecture conducted form-finding analysis to mimic increasing the mesh self-span between the posts. The findings resulted in a substantial reduction in the number of posts required and a more secure fall-restraint system than initially designed.

Replacing the original tension wire design with a mesh barrier significantly reduced the structural loading on the posts, allowing for a smaller number of lighter duty posts, and reducing the cost below the initial estimate.

The concept solution delivered was a dynamic structural design that met the exacting demands of the specification. The design evolved to using laser-fused stainless steel open section beams for the posts, positioned approximately three metres apart with a blackened Carl Stahl X-TEND® stainless steel mesh barrier.

This project is the largest to date in Australia using laser-fused stainless steel structural beams.

Low impact laser-fusion is a process that allows the welding together of pre-polished flat components to a special profile without damaging the visible surface. It provides an effective and economical alternative to extrusions or conventional welds, providing closer tolerances, superior joint integrity and more consistent finishes.

The introduction of laser-fused stainless steel structural beams into the Australian market allowed Freyssinet the flexibility to plan and design with stainless steel in an outcome that was unrivalled for the project scope. Developed and manufactured by Montanstahl (Switzerland) and its subsidiary Stainless Structurals Asia (Singapore), the laser-fused stainless steel structural beams were supplied by ASSDA Sponsor Atlas Steels, as the exclusive agent for the product in Australia.

To this end, Atlas Steels supplied over 30 tonnes of stainless steel for the project, including 316L grade 80x80x6mm I-beam sections for the 530 upright posts, 316 grade 65x65x6mm angle bars for the outrigging, and 316 grade 38.1x1.6mm 320 grit polished tube for the framing of the mesh.
The I-beams supplied were made from a pre-polished strip with a <0.5Ra finish. The I-beam components were laser cut, polished, and then laser-fused together.

Freyssinet rolled the I-beams using a local roll forming company in Eagle Farm to form a curve, following several prototypes to achieve the required design. The beams were then delivered to ASSDA Accredited Fabricator Stainless Engineering Services to cut the posts to the specified height, verify the dimensions, placement and drilling of the holes for the bolt connections, and passivate the posts to ASTM 380 prior to installation.

Stainless Engineering Services also used the offcuts from the I-beams to fabricate the brackets, ensuring no material wastage.

ASSDA Member Anzor Fasteners supplied 550 units of grade 316 stainless steel coupling cables in various lengths of up to 2.1 metres, in 4mm diameter and 1/19 configuration. Each cable was swaged to a threaded stud on one end and a u-shaped fork coupling on the other end. The coupling cables were used to affix the X-TEND mesh to the posts, providing an adjustable method of attachment.

Following the erection of the posts, Ronstan Tensile Architecture supplied and installed 3400m2 of Carl Stahl X-TEND® 316 grade stainless steel mesh constructed from coloured stainless steel wire rope. The stainless steel was blackened with an additional polyester amino resin, which was hardened to the wire under temperature.

The blackened Carl Stahl X-TEND® mesh was the key to achieving an unobtrusive composition and historical aesthetic, while providing the flexibility and tensile strength required for the structure’s design and use of the laser-fused posts.

The structure is a pivotal safety addition to the Story Bridge and exudes functionality in its excellent and unique engineered design. Stainless steel is unmatched in the materials selection for providing durability, structural performance, low maintenance, corrosion resistance and aesthetics.

This article is featured in Australian Stainless Issue 56 (Winter 2016).

Photography by Fullframe Photographics.

Revision of AS 1528: Fluid Transfer in Stainless Steel Tube and Fittings

26 May 2016

Connections are vital

Any visit to a dairy, beverage or food processing plant will drive home the critical importance of the connections between the tanks, mixers, driers, pumps, etc. The image above (courtesy of TFG Group) showing an image of a brewery is a typical example. These tubes and/or pipes carry the process materials, the heating or cooling or wash water, gases, and also dispose of the wastes.

 

Getting the right standard

Except for high pressure or very aggressive environments, most tube is rolled into shape and welded longitudinally. For mechanical or structural service such as columns or handrails, the weld must penetrate and be sound although to perform its mechanical function, it may not need to provide a seal. This is reflected in the basic test requirements of standards such as ASTM A554 ‘Welded Stainless Steel Mechanical Tubing’ and is a reason why it is cheaper and is sometimes used, in error, for fluid transport. Despite these restricted requirements, the external finish is often critical for aesthetic reasons as seen on the handrails in the figure on the right.

Verification of leak tightness is the reason why tubing standards for carriage of fluids, e.g. AS 1528.1 or ASTM A269 or ASTM A270, all include either hydrostatic or 100% eddy current testing. Section 8.4 of the ASSDA Reference Manual summarises the test requirements of the plethora of tubing (and piping) standards commonly used in Australia. However, the food and sanitary industries also require surfaces that are readily cleanable. Hence, in addition to a lack of leaks, there are also requirements on the profile of the weld bead in the tubing, potential crevices in fittings and the surface finish of product contact areas. 

System design and installation

Quite apart from the manufactured components, the system design must include adequate slope for self draining (including across welded joins), simple cleaning procedures, velocities above ~0.5m/sec for low solids streams, at least double that for high solids content and avoidance of design features permitting stagnant zones or dead legs. Excess velocity (at least below about 40m/second) is not a concern for stainless steel, although it may increase noise and pumping costs. These are matters for another place.

Material selection

There are quite complete sets of corrosion resistance data for single corrosives (and some mixtures) at a variety of temperatures and concentrations but they are usually for continuous exposure.  For some acidic, hot and salty fluids or slurries such as sauces, high alloy stainless steels or even nickel-based alloys may be required and such components are rarely “off-the-shelf”. However, for apparently aggressive fluids processed in batches, the intermediate cleaning will arrest the initiation of attack and restore the passive layer so that standard 316(L) material is usually adequate especially with the highly polished finish often used to enable cleanability. One operational issue is that cleaning chemicals can be quite aggressive and the procedures must ensure that residues from cleaning do not remain and are not able to be concentrated and cause corrosion or hygienic issues.

Food tube and fittings – AS 1528

The weld bead is a potential source of crevices and for food tube, its effect must be removed without causing additional surface defects. AS 1528.1 requires the weld bead to smoothly blend without harmful markings. It also sets a nominal surface roughness (0.3 μm Ra) for the rest of the interior by requiring the use of fixed (1.6mm) thickness 2B material. ASTM A270 ‘Seamless and Welded Austenitic and Ferritic/Austenitic Stainless Steel Sanitary Tubing’ assumes a sophisticated specifier as it lists a mill finish as well as multiple alternative mechanical or other finishing techniques. Acceptance of minor surface imperfections is by agreement. The specifier may require a surface roughness (Ra) limit – which, of course, would override a grit size specification.

The manufacturing tests (eddy current or hydrotesting) ensure that food tube will hold pressure. For the essential quality assurance purposes, AS1528.1 requires line marking of tube. Finally, food grade tube requires a complementary set of fittings that will fit together. The AS 1528 suite achieves this with screwed couplings (Part 2), butt welding fittings (Part 3) and clamp liners with gaskets (Part 4). Aesthetics may be important and is in the hands of the specifier as the exterior of AS1528.1 tube may be as-produced or “buff polished as agreed”, i.e. polished with grit of a specified size.

The AS 1528 suite started life in 1960 as AS N32, was split into four parts in the mid 1970s and completely revised by an ASSDA driven working group to its present form in 2001. It has been widely accepted especially since the 2006 publication by ASSDA of what is now the Food Code of Practice for the fabrication and installation of stainless steel process plant and equipment in the food and beverage industries.  The New Zealand dairy industry has effectively adopted the AS 1528 requirements for dairy tube and fittings. Multiple overseas suppliers provide tube to the AS 1528 specification.

Food and beverage manufacture is obviously worldwide and this has resulted in national, regional and international standards which are different and locally focused. The sizes of the ISO alternatives (ISO 2037, 2851 – 3) are quite different. The European standard (EN 10357- which supersedes BS4825.1 and DIN 11850) covers similar tube but does not cover the range of sizes commonly used in Australia. The British Standard products (BS 4825) are similar in sizes to the AS 1528, but with a restricted range. The American 3A products also cover a restricted range. 

“As a result, ASSDA is spearheading an industry effort to revise the 15-year-old suite of AS 1528 standards”.

What is in need of review?

There are a number of typographical errors and inconsistencies between the parts, there are only some pressure ratings and the listing of fittings requires some revisions. The tolerance on the tube wall thickness has been narrow and one sided since inception and while the standard allows modification by agreement, the current wall thickness requirement will be reviewed.  Other issues for discussion will be the addition of larger sizes and assessment of differences for internal finishes between parts of the suite. And finally, it is intended that AS 1528 will be converted to a joint Australian and New Zealand standard to formalise New Zealand’s use.

If users of the AS1528 suite of standards have any suggestions for changes or improvements to the standards, ASSDA would welcome your emailed comments to This email address is being protected from spambots. You need JavaScript enabled to view it..

Acknowledgements

This article has drawn heavily on documents produced by the ASSDA/NZSSDA working group dealing with the proposed revision of AS 1528 and in particular Peter Moore from Atlas Steels, Kim Burton from Prochem Pipeline Products and Russell Thorburn from Steel and Tube in New Zealand.

This article is featured in Australian Stainless Issue 56 (Winter 2016).

Stainless in Color

26 May 2016

A modern and innovative design using coloured and textured stainless steel has left an impressive statement on an Adelaide streetscape.

South Australia’s premier shopping district Rundle Mall underwent a full makeover from 2012-2014 as part of the Adelaide City Council’s initiative to revitalise the precinct.

Part of this redevelopment included a redesign of the facade of a commercial tower at 80 Grenfell Street, housing the Adelaide headquarters of the Bendigo and Adelaide Bank.

Design practice HASSELL delivered an iridescent façade design using coloured stainless steel cladding, supplied by ASSDA Member Steel Color Australia. The extent of the façade referred to as ‘the ribbon’ cascades over 10 storeys, connecting the office tower to the lobby entrance via the retail parapet. The ribbon was made up of over 100 panels that twist and bend over the full height of the building, creating an artistic ripple effect.

HASSELL and Arup’s façade engineering team tested this unique design with physical and virtual models, further refining the design detailing with extensive prototyping. This collaboration with the assistance of Steel Color Australia’s product and material knowledge ensured this remarkable design element was feasible.

Stainless steel was specified for this design as its inherent properties allowed for the level of manipulation required to construct the architect’s creative expression, as well as provide a high quality and aesthetically pleasing finish.

Over 1500m2 of grade 304 stainless steel in 4000x1250x1.2mm sheet in a Rosso colour (Italian for red) was supplied by Steel Color Australia, as the sole distributor in Australia and New Zealand for embossed, coloured, mirror finished and textured stainless steel manufactured by Steel Color S.p.a in Italy.

Steel Colour Australia owner Vince Araullo said that electro-colouring (INCO system) is the main technology in Steel Color Australia’s production. ‘The stainless steel sheet’s surface was directly altered, chemically stimulating the natural passivation of the material. No painting was involved in the process, increasing the pitting resistance of the stainless steel.’

In terms of manipulating the steel’s shape, Araullo said that colouring is an intrinsic part of the stainless steel. ‘This means the stainless does not lose colour during shaping, as opposed to aluminium for example which would need to be coloured after folding due to the fragility of the coloured anodic coating.’

Steel Color Australia facilitated the overseas production of some 270 sheets, weighing 10 tonnes and their shipment to the project site. Modular framework was constructed to bend the stainless sheets into shape for easy installation on site by crane.

The visually striking building façade integrates impressively into the Rundle Place precinct, and the outcome has resulted in a virtually maintenance-free and colour enduring structure.

This article is featured in Australian Stainless Issue 56 (Winter 2016).

Images courtesy of Steel Color Australia.

Stainless Delivers State-of-the-Art Production Facility

26 May 2016

Stainless steel has helped deliver improved environmental performance and increased efficiency for a major food production company.

In 2014, Australian agribusiness GrainCorp announced a $125 million investment in a consolidation strategy to integrate its GrainCorp Foods’ manufacturing operations, including the relocation of its Brisbane plant to the existing West Footscray facility in Victoria. This move effectively terminates the use of its coal-fired equipment, giving GrainCorp Foods the opportunity to invest in efficient and environmentally sustainable technology and significantly reduce its carbon footprint.

As a result, GrainCorp Foods’ West Footscray operation commenced its expansion and upgrade in 2015 to deliver a state-of-the-art food processing plant.

GrainCorp awarded the design, engineering and installation to SPX Flow Technology Australia, and SPXFlow awarded ASSDA Member and Accredited Fabricator TFG Group the contract to install and fabricate specialised components for the facility’s new margarine production line.

TFG Group’s Foodline Projects division installed and assembled the stainless steel equipment under the direction of SPX Flow Technology Australia, including numerous pumps, valves, heat exchangers, vessels and specialised processing equipment.

The TFG Foodline Projects team also mechanically installed over 12km of stainless steel pipe, AS 1528 304L and 316L tube ranging from 25mm to 100mm in diameter, and over 6000 fittings supplied by ASSDA Sponsor Prochem Pipeline Products.

Hygiene and cleanability of equipment used in food production is paramount, and the correct specification and fabrication quality of stainless steel ensured this criterion was met.

The TFG Foodline Projects team consisted of 35 specialised welders, fitters and installation specialists to ensure the project’s tight lead-time of 24 weeks to completion was met with zero safety incidents. Orbital welding was applied to ensure speed, accuracy and prevention of bacterial contamination in the products.

As part of the factory upgrade, TFG Group’s Austline Fabrications division assisted with the fabrication and installation of the specialised scalloped stainless steel tank access platforms, break tanks, stainless steel chemical bunds and support racks. Jacketed pipework was fabricated to ensure the internal temperature of the process pipework was controlled to prevent the viscous product from solidifying.

These specialised items were all fabricated at TFG Group’s purpose-built factories in both Western Australia and Victoria, and transported to the West Footscray facility for installation by the Foodline Projects division.

GrainCorp’s investment in its West Footscray plant has delivered a fully integrated facility and a more efficient focal point for the sourcing, refining, and distribution of GrainCorp’s locally-produced edible oils and food ingredients.

This article is featured in Australian Stainless Issue 56 (Winter 2016).

Images courtesy of TFG Group.

A Walk to Remember

12 June 2015

The spirit of the Anzacs is evoked in a new architecturally stunning, stainless steel walkway that unfolds around Newcastle’s cliffs and links Strzelecki Lookout to Bar Beach.

 The much-anticipated Newcastle Memorial Walk opened on 24 April 2015 on the eve of the Anzac centenary, and features spectacular 360-degree views of Newcastle city and coastline.

The 450m raised walkway forms part of Newcastle City Council’s ‘Bathers Way Project’, a $29 million foreshore development and revitalisation program to link Merewether Beach with Nobby Beach via a coastal walk. The total cost of the walkway was $4.5 million, $3 million of which was contributed by BHP Billiton to mark their 100-year anniversary since the commencement of steel making in the Hunter region.

In commemoration of the Anzacs the walkway features silhouettes of soldiers, laser cut from 10mm thick weathering steel, specified to withstand the coastal wind load. These silhouettes are engraved with 3,860 family names of almost 11,000 known Hunter Valley men and women who served in the Australian Imperial Force, Royal Australian Navy, Australian Army Nursing Service and British and Commonwealth forces during World War 1 from 1914-1918.

EJE Architecture carried out the detailed design work, and lead architect Barney Collins said the historical significance of the project site inspired the walkway’s sinusoidal design.

“During the design phase, we looked at the history of the site and build location next to Memorial Drive, which was originally constructed in 1922 to pay tribute to the soldiers who fought in World War I,” Collins said.

“The design concept of what is commonly known as ‘the wave effect’ was drawn on the fact that DNA was used to identify the human remains of soldiers, and this process stood as the connection between the soldiers and their families.”

Constructed by Waeger Constructions and engineered by Northrop Engineers, the walkway has a structural design life of 70 years, as required by Newcastle City Council. Grade 316L stainless steel was specified due to its sustainable, corrosion resistance and ductile properties. The cliff top location of the walkway overlooking the Pacific Ocean was also a determining factor given the high wind and salt exposure.

ASSDA Sponsor Atlas Steels supplied 64 tonnes of stainless steel for the walkway including DN150 x 10.7mm, DN125 x 6.5mm, and DN65 x 5.1mm wall pipe; 200mm x 100mm x 6mm rectangular hollow sections and 100mm x 100mm x 5mm square hollow sections for the bridge section frames; and 16mm diameter round bar and 50 x 2mm and 50 x 3mm round tube for the handrails and balustrades.

Good scheduling and planning ensured on-time delivery of the stainless steel over a period of 14 weeks, which was sourced from three overseas mills. Positive material identification (PMI) testing was performed by the mills on all stainless steel supplied to ensure the specified grade of 316L was delivered.

Fabricated and installed by ASSDA Member and Accredited Fabricator SGM Construction & Fabrication, the 160m of stainless steel bridge sections consist of eight, 20m single spans (four under trusses and four over trusses) each weighing 6.5 tonnes. The frame of each section is fabricated from 12 square hollow sections welded to two rectangular hollow   sections, and the walking surface is laid over the frame. On either side of the truss, the wave-like effect was created by bending and rolling wall pipe to sweep above the frame for the over trusses and below the frame for the under trusses.

Seven Y-shaped precast concrete pylons up to 8.8m high and 3.4m wide, and two abutments, support the bridge sections of the walkway that reach up to 9m above the ground.

The decking of the walkway was laid with fibre-reinforced plastic, and being a non-structural component, was specified with a 44-year design life. The safety aspects of the bridge are completed with hand railings, which are welded on to the bridge trusses inside the curved pipe sections.

Over 760m of handrails and 600m of vertical balustrades cover the length of the bridge, specified with a maximum Ra value of 0.5. ASSDA Member Australian Pickling & Passivation Service was contracted to electropolish the balustrades and pickle and passivate the completed bridge sections. A purpose-built electropolishing unit, consisting of six baths, was set up to handle and achieve the specified finish of the 1.5m high x 6m long balustrade panels each weighing 180kg.

With an allotted fabrication period of only four months, SGM Fabrication & Construction manufactured the bridge sections using its 2000m2 workshop to full capacity to meet the critical deadline for Anzac Day.

As the walkway runs parallel to Memorial Drive, the main thoroughfare from King Edward Park to Merewether Beach, the erection of the pylons and installation of the bridge sections took place only during a 10-hour window over two nights to avoid prolonged temporary road closures.

Coastal undermining was a challenge for the structural engineers, however good design and construction ensured environmental protection of the sensitive coastal site to minimise erosion.

Mr Collins said the key to the project’s cost control and overall success was the engagement of local contractors.

“The direct involvement of each contractor’s Directors ensured seamless communication and full control of each project phase. The walkway is already an icon for Newcastle, and everyone who has worked on the project is thrilled over its success,” Collins said.

More than two million people visit Newcastle’s beaches every year, and the Newcastle Memorial Walk is already one of Australia’s most remarkable coastal walkways and a significant World War I tribute.

  

This article is featured in Australian Stainless Issue 55 (Winter 2015).

Images courtesy of Bryce Thomas.

Welding Dissimilar Metals

12 June 2015

Welding the common austenitic stainless steels such as 304 and 316 to each other or themselves is routine and the easiest of fusion welding. Nevertheless, there are many situations where it is necessary to weld stainless steel to carbon steel. Two common examples are balustrade posts attached to structural steel or doubler plates connecting supports to stainless steel vessels. There are differences in physical properties such as thermal conductivity and expansion, magnetic properties, metallurgical structure and corrosion resistance, which all require attention. This article outlines the necessary procedures for satisfactory welding, including reference to standards, and explains the necessary precautions. Appendix H of AS/NZS 1554.6:2012 has a more detailed technical discussion including advice on welding carbon steel to ferritic, duplex and martensitic stainless steels.

 Welding process
The normal TIG and MIG welding processes are suitable for welding austenitics to carbon steel. As a guide, welding should be carried out at ambient temperature with no pre-heating required (except possibly for drying), unless the carbon steel has more than 0.2% carbon or a thickness of more than 30mm and giving high restraint, in which case a preheat of 150°C is usually adequate. Because carbon steels are susceptible to hydrogen cracking, the consumables and the weld area must be dry.

Weld area preparation
When welding galvanised steel (or steel coated with a zinc rich coating) to stainless steel, it is essential to remove the zinc from the heated zone because it is possible to get zinc into the weld, which will cause liquid embrittlement and cracking along the zinc penetration line. It is possible that fume from the zinc coating will cause Occupational Health and Safety (OHS) problems. The weld areas of stainless steel must also be clean and free from grease or oil, as the contaminants will cause carbon pickup and possible sensitisation, leading to intergranular corrosion.

In addition, because the nickel content of the austenitics makes the weld pool more viscous, the weld preparation must be more open (see Figure 1) and the root gap larger to allow wetting. Consumables with added silicon (Si) also assist with edge wetting. An additional effect of the nickel content is that the penetration into the no-nickel carbon steel will be greater than into an austenitic stainless steel (see Figure 2).

Welding consumables (filler metal and gases)
Carbon steel must not be welded directly to austenitic stainless steels as the solidified weld metal will form martensite, which has low ductility and which, as it contracts, is likely to crack. There is an easy way to select the higher alloy filler, which will dilute to give the correct austenitic microstructure with enough ferrite to avoid shrinkage cracks. Refer to Table 4.6.1 in AS/NZS 1554.6. Another way is to use a Schaeffler deLong diagram (see Figure 3) or the WRC 1992 diagram as described in Appendix H2 of AS/NZS1554.6. The standard recommends that carbon steel to 304(L) uses 309L, and carbon steel to 316(L) uses 309LMo.

If nitrogen additions are used, care is required as it will decrease the ferrite content of the weld metal, which may cause hot cracking.

The shielding gas must not include the oxygen often used in carbon steel mixtures. If an active gas is desired, then low levels of CO2 can be used.

 

Thermal expansion
There is a degree of distortion inherent in welding a low thermal expansion carbon steel to a high thermal expansion austenitic stainless steel. The expansion coefficient for mild steel is approximately 12 compared to 17 μm/m/°C for stainless steel in range 0 – 300°C. There is also the difference between the good heat conduction of the carbon steel compared to the poor heat conduction of the stainless steel (49 to 15 W/m°K at 200°C respectively), which means that the stainless steel will cool (and contract) more slowly than the carbon steel, especially if the welded sections are thick. 

To control distortion, the heat input should be minimised and the joint tacked before making the full weld run. One trick is to tack the ends, centre, 1/4 points and possibly 1/8 points in that order. Heat input and interpass temperature recommendations for stainless steel welding are given in section 5.10 of AS/NZS 1554.6.

Post weld cleaning
After welding, clean the weld area to remove slag and heat tint to examine the weld integrity and also to allow the metal to be painted. If possible, blast the weld area with iron free grit but if that is not possible, grind along the weld line to avoid dragging carbon steel contamination onto the stainless steel. ASTM A380 has recommendations for passivation solutions for mixed mild and stainless steel welds. The formulations include peracetic acid and EDTA (ethylenediaminetetraacetic acid), but mechanical cleaning alone is the most common method.

Corrosion protection
It is assumed that the carbon steel will be painted for corrosion protection. When a barrier or insulating coating is used for painting the carbon steel, carry the paint onto the stainless for up to 50mm (depending on the environment’s corrosivity) to cover the stainless steel that has been heat affected. Figure 4 shows a carbon to stainless steel weld with an inadequate coating. Normally in a stainless to stainless weld, the welded fabrication would be acid pickled and passivated using a hydrofluoric/nitric acid mixture, but this is clearly not possible for a carbon steel to stainless steel fabrication because of the corrosive effect on the carbon steel. If the weld zone is to be exposed to corrosive conditions, and it is intended to use a zinc rich final coating on the carbon steel, a stripe coating of a suitable barrier paint is required along the edge of the zinc coating to avoid possible galvanic dissolution of the zinc coating adjacent to the stainless steel.

Stainless clean up
Quite apart from any weld to carbon steel, the stainless steel away from the weld area must be protected from contamination during fabrication. This includes weld spatter, carbon steel grinding debris and smearing of carbon steel on the stainless caused by sliding contact between carbon and stainless steels. If contamination occurs, then it must be removed either by mechanical means, followed by use of a nitric acid passivation paste or by the use of pickling and passivation paste. Passivation paste will not affect the surface finish of the stainless steel, whilst pickling and passivation paste will etch the stainless steel. All acids must be neutralised and disposed of according to local regulations. The surfaces must also be thoroughly rinsed after the acid processes.

Further reading
NI #14018 “Guidelines for welding dissimilar metals”
NI #11007 “Guidelines for the welded fabrication of nickel-containing stainless steels for corrosion resistant services”
IMOA/NI “Practical guidelines for the fabrication of duplex stainless steels” (3rd edition)
ISSF “The Ferritic Solution” (page 36) deals generally with welding ferritic stainless steels
AS/NZS 1554.6:2012 “Structural steel welding: Part 6 Welding stainless steels for structural purposes”
Herbst, Noel F.  “Dissimilar metal welding” © Peritech Pty Ltd 2002 (available for download from here)

This article is featured in Australian Stainless Issue 55 (Winter 2015).

Stainless Steel in Western Australia Subsea Applications

12 June 2015

Stainless steel is the material of choice for subsea hydraulic and control line applications because of its excellent corrosion resistance, material strength benefits and weldability.

 Subsea production in the oil and gas industry involves offshore, in situ equipment to facilitate the exploration, development, production and transportation of energy reserves from underwater fields. It is a viable form of oil and gas production, providing economic, productivity and environmental benefits.

Perth-based ASSDA Member and Accredited Fabricator Diverse Welding Services (DWS) recently completed detailed design and fabrication works on two major subsea projects operated by multinational oil and gas exploration and production companies.

Apache Corporation’s Coniston and Novara Redevelopment Project, completed in February 2014, is a subsea oil field located 65km north of Exmouth. The project involved an upgrade to the Ningaloo Vision floating production, storage and offloading (FPSO) unit and development of the neighbouring Coniston and Novara oil fields, which links these fields into the existing Van Gogh manifolds via dual production flow lines. The equipment operates in water 340 to 400m deep.

DWS was contracted to detail the design, fabrication, installation and NDT testing of the small-bore hydraulic control and chemical injection lines for five subsea production manifolds.

2,380m of 316L stainless steel wall tube in various sizes ranging from 0.375” OD x 0.083” up to 1.000” OD x 0.156” was used, plus 30m of Inconel 625 0.750” OD x 0.134” wall tube.

Chevron Australia’s Wheatstone Project, located 12km west of Onslow on the Pilbara coast of Western Australia, is one of Australia’s most significant LNG projects. Currently in progress and at almost 60% complete, it will become the country’s first third party natural gas hub. DWS was contracted to fabricate, install and test small-bore tubing and free issue components to Multiple Quick Connect (MQC) plates. The main free issue components consisted of logic caps, cobra heads, single line couplers and acid injection items requiring small-bore interconnecting tubing on four MQC plates serving the subsea isolation valves (SSIV) for the 44” trunkline, 24” and 14” flowlines, and the 18” APACHE/KUFPEC line.

SAF2507 super duplex stainless steel was used for the MQC plates including over 80m of 0.625” OD x 0.083” wall tube, 20m of 316L 0.375” OD x 0.083” wall tube and 130 Swagelok 90° elbow butt-weld fittings. The MQC plates were fabricated by PT Profab Indonesia, then shipped to DWS in Perth for detailed fit-out using autogenous orbital welding processes. After testing, the completed MQC plates were shipped back to PT Profab Indonesia for installation into the SSIV manifolds.

All welding by DWS for both projects was completed using an autogenous orbital welding process, specified by the clients for the small-bore hydraulic tubing welding due to its excellent control of welding variables, repeatability of application and maximisation of corrosion resistance of exotic materials. DWS produced high quality welds that when tested under the G48 Method A – Pitting Resistance Testing, proved resulting weight loss to be less than 0.36g/m2.

Orbital welding is an automatic method of Tungsten Inert Gas (TIG) welding of thin tubes, usually without filler wire. Its advantages are a uniform weld profile and excellent gas shielding giving minimal heat tint. The ends of the tube are prepared and clamped in an enclosed head, which is flushed with external shielding and internal purging gas – usually argon, although gas mixtures can be used. The cycle starts by striking the arc and proceeds as the head slowly rotates around the tube. A specific weld head can deal with several diameter tubes. The weld is usually in the centre of the head, although heads are available for offset joins used with joints to elbows or valves.

DWS completed 1200 welds for the Coniston and Novara Redevelopment Project and 204 welds for the Wheatstone Project, which passed 100% radiographic/liquid penetrant testing in accordance with ASME B31.3 NFS. The excellent gas and heat input control of the orbital welding produced internal surfaces that did not require post-weld cleaning. The external surfaces around the welds were abrasively treated as required for aesthetics reasons.

The DWS facility includes five autogenous welding machines complimented with seven welding heads of assorted ranges allowing DWS to complete weldments from 0.25” OD to 6” OD tube/pipe schedules as required for these project works. This coupled with their extensive range of other qualified weld procedures for this process allows DWS to meet clients’ stringent fabrication, application and quality specifications.

         

This article is featured in Australian Stainless Issue 55 (Winter 2015).

Under the Sun

12 June 2015

‘Under the Sun’ is a 1300kg, 6.5m diameter suspended stainless steel sculpture that embodies a symbol of the moon floating over the earth, and casts filigreed shadows under the sun. It is an inspiring architectural piece featured at the entrance of Stockland’s Point Cook Town Centre in Victoria, and was completed in 2014 as part of the shopping centre’s $20 million revamp.

 The sculpture is an expression of the relationship between the moon and the sun, opening a space for visitors to reflect in moments of perspective and wonder. The sculpture’s concept was also inspired by the traditional feminist symbol of the moon, celebrating the role of women in the Point Cook community and embodying the role of nature in the life and tides of the local Bellarine Peninsula Wetlands.

It was designed by Melbourne artists Robert Owen and Joanna Buckley, engineered by Anthony Snyders of Adams Consulting Engineers, and fabricated by the artists in collaboration with Jeph Neale of Artery Cooperative and Luke Adams of Eco Electrics. The intricate detail in the sculpture was laser cut by Arrow Laser.

The sculpture’s face panels and reinforcing ring beam were made using grade 316 stainless steel, specified for its excellent corrosion resistance. It is suspended between the building and a 10m high mast, using 22 grade 316 stainless steel cables of diameters 4mm, 7mm, 8mm and 10mm and of varying tensile strengths up to 71kN.

The complexity of the suspension and installation of the sculpture required 3D modelling, detailed structural analysis, design and documentation which was undertaken by Anthony Snyders in consultation with ASSDA Member Ronstan Tensile Architecture (a division of Ronstan International).

This analysis and modelling allowed Ronstan Tensile Architecture to manufacture cables to the exact lengths that would see the 1300kg sculpture held securely in the designed position, taking into account the weight of the structure, cable stretch, cable creep (elongation over time) and wind loads. The bending of the mast and loads applied to the building were also defined by the analysis and considered in the design and installation.

Ronstan Tensile Architecture’s General Manager Rowan Murray said 3D modelling and analysis was a critical step in accurately predicting the structural behaviour and performance of cable structures. Applying this science upfront assures these structures are installed as designed and mitigates many of the risks of suspending art in the public realm.

In addition to consultation for the structural design of the cable support structure, Ronstan Tensile Architecture’s project scope included the manufacture of the cables, installation of the foundations, the mast, brackets to the existing building, and the lifting and suspension of the sculpture.

ASSDA Member MME Surface Finishing was also engaged to mechanically and chemically polish the stainless steel sculpture to provide maximum protection against tea staining and corrosion, whilst presenting an architecturally pleasing surface finish. Firstly, 3 x 1.5m stainless steel plates were mechanically polished to a No. 6 Finish, 320 Grit (0.5μm Ra Max) ensuring a smooth and consistent linished finish. Once laser cut and fabricated, MME Surface Finishing pickled, passivated and electropolished the panels and rings.

The end result of this successful collaboration is an impressive sculpture with an outstanding balance of aesthetics, geometry, constructability and durability.

This article is featured in Australian Stainless Issue 55 (Winter 2015).

Images courtesy of John Gollings.

Star Light, Star Bright

21 October 2014

The magic of a clear night sky filled with stars has inspired many creative souls. Now, through a collaboration between science and art, a stainless steel sculpture installed at the Australian National University in Canberra brings new depth to the connection between ourselves and the stars above.

The 4 metre diameter, mirror-polished stainless steel sphere (called UNA), which sits in the science precinct at ANU, is so much more than first meets the eye. Designed by UK artist Wolfgang Buttress, UNA features 9,100 laser-cut perforations, which were mapped in collaboration with ANU astrophysicist Dr Daniel Bayliss.

The holes match the 9,100 stars that we can see with the naked eye from Earth and vary in size according to the brightness of the stars in the night sky (the brighter the star, the larger the hole).

Inside the sphere sits a second, two metre diameter mirror polished, stainless steel sphere. When viewed through one of the outer perforations, the internal sphere reflects small points of light from the outer sphere, creating, according to Mr Buttress, a microcosm of our perceived night sky.

“One makes connections to one self and the stars above. We are all made from stardust,” he said.

The magic enters a different realm at night, thanks to the fibre optic lights that sit in the centre of the two spheres, casting a glow through the perforations.

Mr Buttress said the use of stainless steel and high quality fabrication were integral to the success of the project.

Aside from the ability to be mirror polished, he said stainless steel was specified due to its strength, resilience and, if maintained properly, the fact that it will look as good in 50 years as it does now.

The spheres incorporate around 2000kg of 4mm 316L, 2B finish stainless steel, which was supplied in 24 pieces by ASSDA Major Sponsor Sandvik Materials Technology (now Vulcan Stainless). The pieces were laser cut to shape in-house on one of Sandvik’s four laser machines. Sandvik VIC/TAS State Manager Stephen Orridge said each hole was unique in its shape and the work involved about 40 hours of programming.

The sheet was pressed by Dished & Flanged Ends to create the curved forms for both the inner and outer spheres. ASSDA Member and Accredited Fabricator NRG Piping then joined and welded each segment with only 1mm tolerance, followed by polishing. NRG Piping co-ordinated the fabrication, transport and installation of UNA.

Mr Buttress said the welding had to be done carefully to minimise distortion as all would be seen when it was mirror polished. “There is nowhere to hide. NRG Piping are amazing fabricators as they totally understand the properties and essence of stainless steel,” he said.

Because the inner sphere had to be positioned inside the outer sphere during the fabrication process, a 600mm hole at the base allowed enough room for a welder to get access inside to polish out the internal welds.

The end result is one of the artist’s favourite pieces that he has created. “By day, the inner world is revealed on close inspection and at night it has a different character as light pours out of her like a beacon. It works on a micro and macro level, at day and by night. It was a great marriage between art, architecture and engineering,” Mr Buttress said.

Images courtesy of Ben Wrigley.

This article is featured in Australian Stainless magazine issue 54, Spring 2014.

General Corrosion Resistance

The normal state for stainless


21 October 2014

Stainless steels resist corrosion because they have a self-repairing “passive” oxide film on the surface. As long as there is sufficient oxygen to maintain this film and provided that the level of corrosives is below the steel’s capacity of the particular material to repair itself, no corrosion occurs. If there is too high a level of (say) chlorides, pitting occurs. As an example, 316 works well in tap water (<250ppm) all over Australia, but will rapidly corrode in seawater because seawater has very high chloride levels (20,000ppm).

If there is not enough oxygen and the local corrosives are not high enough to cause pitting, then general corrosion can occur. This might happen in a crevice (which has very limited oxygen) or in a strong, reducing acid (such as mid concentrations of sulphuric acid). General corrosion can occur when there are stray currents flowing from stainless steel to ground. This can happen in mineral extraction if the bonding arrangements are inadequate during electrowinning. General corrosion may also occur from galvanic effects, e.g. if a conductive carbon gasket is used on stainless steel in an aggressive environment.

QUANTIFYING CORROSION RESISTANCE
For circumstances where general corrosion is expected, graphs are available called iso-corrosion curves. They plot the effect of a single chemical and corrosion rate for temperature against concentration. An example is the graph below of a 42% nickel alloy 825 in pure sulphuric acid with air access. This graph shows that the corrosion rate increases with temperature and that provided the temperature is less then ~45°C and a corrosion rate of 0.13mm/year is acceptable, alloy 825 would be suitable for any concentration of pure sulphuric acid. The boiling point curve is often included to show the limits of data at atmospheric pressure.

 

 

Most of the following graphs are from the Outokumpu Corrosion Handbook. The specific alloy compositions are tabulated in that Handbook and in the Appendix of the ASSDA FAQ 8.

However, a series of graphs each showing the results for one material over the full range of concentrations and temperatures is cumbersome and so multi-material plots are used for the initial material selection. Titanium is frequently included because of the widespread expectation that it is the “super” solution – although the data shows this is not always correct.

The two graphs below show data for austenitic and duplex stainless grades in pure sulphuric acid. However, only the 0.1mm/year lines are drawn for each alloy because it is assumed that a loss of 0.1mm/year would be acceptable for continuous exposure during 365 days per year. This assumption may not be acceptable if, for example, the process using the acid required very low iron levels. For each material, the temperature and concentrations of pure sulphuric acid that are below the line would mean a corrosion rate of less than 0.1mm/year.

 

WHAT ABOUT IMPURITIES OR ADDITIVES?
The graphs below show (and note the temperature scale changes from earlier graphs) the dramatic reduction in corrosion resistance when 200mg/L of chlorides are added to sulphuric acid or ten times that amount, i.e. 2,000mg/L. The heavily reducing range from about 40% to 60% acid concentration  defeats even the high nickel 904L and 254/654 grades.

Nevertheless, a number of grades are potentially suitable for concentrations below 20% sulphuric even with significant chlorides.  However, the graphs also show that at the other end of the concentration scale, the oxidising conditions, which occur for sulphuric acid above about 90%, are extremely aggressive if the acid is impure.

 

 

Some additives act as inhibitors to corrosion and this can be critical in selecting suitable materials for mineral extraction processes.  For example, the graph below shows that adding iron ions to sulphuric acid improves the resistance of 316.  Adding oxidising cupric ions has a similar effect but as with any inhibitor, attack can occur in crevices where the inhibitors may be used up.  And despite the requirement for oxidising conditions to ensure  stability of the stainless steel’s passive layer, it is possible to add too much oxidant as shown by the positive effect of small additions of chromic acid followed by a  reduction in corrosion resistance if more chromic acid is added.  It is relatively common to refer to the redox potential (rather than concentrations of oxidising ions) if the chemistry is not simple.

 

The data in this section is intended to show that while these iso-corrosion graphs are useful in predicting corrosion rates for specific pure compounds, the addition of aggressive ions, oxidisers or crevice conditions require more detailed consideration.

MATERIALS SELECTION FOR OTHER CHEMICALS
A very common chemical is phosphoric acid, which is used in cleaning, pre-treatments, food preparation and a host of other applications.  It requires increasing chemical resistance with high temperatures and concentrations. For pure phosphoric acid, the iso-corrosion curves show a progression from ferritic 444, through the austenitic 304, 316, 317 to 904L.  This is not an oxidising acid so although it removes iron contamination, it does not strengthen the passive film on stainless steels.

Phosphoric acid is frequently associated with chloride or fluoride ions especially in production from rock phosphate.  The variation in composition in this wet process acid (WPA) means that iso-corrosion plots are of limited use.  However, with thermally produced acid and various impurities, a plot of corrosion rate vs. contaminant ion concentration may be used instead of an iso-corrosion graph – in this case chlorides with the 2.5% molybdenum version of 316.  This data is for exposure 24 hours a day, 365 days a year.  Note that while the two graphs do not overlap, the trends of these different experimental plots do not exactly match, i.e. iso-corrosion curves provide trend data and not precise values.

 

 

ACIDS FOR CLEANING STAINLESS STEELS

Both the chelating oxalic and citric acids, and the oxidising nitric acid, are widely used on stainless steels both for cleaning and passivation as shown in ASTM A380 and A967. Nitric acid can be used at elevated temperatures and low to medium concentrations without concern for the standard austenitics. However, at high concentrations and above ambient temperatures, they can suffer intergranular attack, unless a low carbon grade is used. In the same environment, molybdenum-containing grades may suffer intergranular attack of the intermetallic phases such as sigma.

 

ALKALIS
As shown by the plot, austenitic stainless steels are resistant to general corrosion for all concentrations of sodium hydroxide and, for high concentrations, the usual problem is lack of solubility. However, at near boiling temperatures, austenitic stainless steels (and especially those with extensive chromium carbide precipitates) are susceptible to cracking as shown by the shaded area.

 

 

SUMMARY
If you intend to use a stainless steel with a new, relatively pure chemical, iso-corrosion curves offer an initial guide to the temperature and concentration limits against general attack. If there are contaminants or oxidants present, then the corrosion susceptibility can increase or decrease significantly and specialist advice should be obtained.

This technical article is featured in Australian Stainless magazine issue 54, Spring 2014.

Riverwalk Reborn

21 October 2014

Brisbane's New Farm Riverwalk is one of the city's beloved icons. Originally constructed in 2003, the Riverwalk was used daily by over 3000 cyclists, pedestrians and runners before it was washed away during the 2011 floods.

After a construction period of nearly 18 months, Brisbane City Council’s re-imagined New Farm Riverwalk has now opened to the public, connecting New Farm to the Brisbane City via the Howard Smith Wharf Precinct.

Engineered by Arup, the Riverwalk has a design life of 100 years and sits 3.4m above mean sea level on robust piles.

Critical to its design and life expectancy is the extensive use of stainless steel for both structural and aesthetic purposes.

Brisbane City Council’s two key objectives of the project were to achieve a low maintenance, durable structure while achieving high aesthetic qualities. Stainless steel was deemed suitable to achieve both objectives while also providing the necessary strength required.

Key design elements featuring stainless steel include balustrades, skate stops, help point enclosures, light posts, signage, electrical enclosures, deck furniture and bins at the node structures. For additional durability, stainless steel reinforcement conforming to BS10088 and BS 6744:2001 was used in the soffit of the precast concrete girders where the structure could be subject to wetting and chloride contamination in the future.

Constructed by John Holland, the project involved a high level of collaboration between multiple suppliers and fabricators to meet the exacting demands of the specification.

John Holland Project Engineer Cameron Pahor said one challenge was programming works in accordance with project specifications to reduce contamination between carbon steel and stainless steel, both of which were used within the precast concrete girders incorporated into the Riverwalk.

Modelling of the reinforcing in 3D by Vectors Computer Aided Drafting also meant exact dimensions were ascertained, reducing waste of stainless steel reinforcing.

ASSDA Sponsor Valbruna Australia Pty Ltd’s Queensland construction division was contracted to supply 385 tonnes of stainless steel reinforcing bar, with The Australian Reinforcing Company (ARC) sub-contracted to schedule, cut and bend the rebar in a specifically prepared quarantine location to prevent processing and storage contamination issues.

Valbruna Special Products Manager Scott Ford said the majority of the rebar (in diameters ranging from 12mm to 40mm) was produced to precise precast tolerances predominantly using Reval® special Grade AISI 2304 (1.4362). Grades 2205, 316L and 304L were also used due to the unexpected increase in tonnage required: nearly 40% more than original project calculations was required, making the Riverwalk the largest use of stainless steel rebar in Australia to date.

Mr Ford said stainless steel rebar ensured the Riverwalk met the required 100 years life cycle, while minimising ongoing maintenance costs.

“Using stainless steel rebar ensures that a landmark structure such as the Riverwalk is kept open to the public rather than lengthy maintenance closures due to corrosion issues,” he said.

Down time was also minimised during construction, with Valbruna holding extensive stocks on the floor in both Italy and Australia of stainless Reval® rebar, enabling delivery to site within 48-72 hours of final approval of drawings. Manual templates were produced for many of the bars to ensure the accuracy of the bends and eliminate site down time.

Minimising maintenance for the visual elements of the Riverwalk was also a priority. To this end, ASSDA Sponsor Midway Metals supplied 275 tonnes of grade 316 stainless steel and two tonnes of welding consumables for the construction of around 1900m of balustrading. Midway also supplied 100 litres of Avesta pickling gel that was used to passivate all welds on the balustrades.

Midway Metals Brisbane Branch Manager Sean Lewsam said some of the specified handrail sizes were not available in Australia (e.g. 150x50x6mm rectangular hollow section or RHS) and had to be air freighted in to meet strict deadlines.

Midway supplied the project with 3,522 metres of RHS, 14,500 metres of round bar, 1,924 metres of HRAP (hot rolled, annealed, pickled) flat bar, 1,500 metres of flat bar from their slitting and flat bar machines, and 2,000 metres of mirror tube, storing the material in a dedicated holding area for the duration of the project.

Specific-sized Grade 316 plates were acquired (132 tonnes in total ranging from 10mm to 16mm) to minimise off cuts and wastage during the plasma cutting of stiffener plates, 1500 base plates and 1000 staunchions for the balustrades. Around 26 tonnes of laser cut profile plates ranging from 5mm to 20mm were also supplied.

ASSDA Member Southern Stainless was contracted to fabricate and install three different types of balustrading (solid uprights, mesh wire and glass infill), as well as the other visible stainless steel elements of the project using the stainless steel and welding consumables supplied by Midway Metals.

Southern Stainless General Manager Matthew Brown said all stainless steel components were manually polished to a 600 grit finish prior to assembly and welded in compliance with AS1554.6. After fabrication, the 960 balustrades panels (each weighing between 180 and 220kg) were electropolished in-house to Ra<0.5 and then hand polished with silicone-based polish prior to being wrapped and delivered to site for installation. The end product is both visually appealing and certain to stand the test of time.

Strength testing was undertaken for the balustrade/girder connections to ensure the stainless steel couplers, bolts and ferules (supplied by ASSDA Member Ancon Building Products) would not damage the cast-in items during a flood occurrence.

Riverwalk’s robust design makes it resilient to future flood events. The opening span has been relocated to reduce the likelihood of debris getting caught on the structure, and some elements have been designed to collapse in extreme events (rather than withstand the flood waters), reducing the force on the piles.

With the re-imagined Riverwalk now a fixture on the Brisbane’s riverscape once again, residents and visitors can look forward to enjoying the unique experience that Riverwalk offers well into the future.

This article is featured in Australian Stainless magazine issue 54, Spring 2014.

Grand Designs

21 October 2014

A grand ballroom demands high impact aesthetics combined with maximum functionality, both of which have been supplied in spades at the recently refurbished RACV Royal Pines on Queensland's Gold Coast

Central to Stage 1 of the award-winning refurbishment is a 55 metre long and 5 metre high floor-to-ceiling glass wall anchored and framed by nearly a tonne of stainless steel wire rope and fittings. The wall ensures an impressive visual impact, as well as enabling a flood of natural light, a stunning view, and flexible exhibition options.

Designed by Joseph Pang Design Consultants and project managed by Schiavello Constructions, ASSDA Member Structural Dynamics (Australia) Pty Ltd (Strudyna - an entity under the Arcus Wire Group) was contracted to work with Queensland Glass to meet the demanding needs of the wall’s design.

Strudyna Architectural Manager Ross Munro said the installation was extremely complex, as well as being the team’s first retrofit glass façade project involving engineering, supply and installation.

The client requested a vertical cable truss, internal glass façade and mirror polished fittings to ensure a high-end finish to compliment the refurbishment.

Mr Munro said the retrofit installation meant there were many challenges associated with working with an existing engineered structure.

“The suspended concrete floor had been built to a specific load capability and included post-tension cables within the concrete floor that had to be accommodated. This affected the loads that could be applied to the cable truss to keep the structure rigid, while considering slab deflection with loads from occupancy,” he said.

The cable truss façade featured frameless hinged doors that were also emergency exit doors, so there were no horizontal cable elements to stabilise the  trusses.

Around 926kg of grade 316 stainless steel were used in the job, including fittings/castings and 8mm and 12mm Hamma X-Strand. Hamma X-Strand is stainless steel wire strand with a high quality shine finish manufactured by KOS in South Korea to Arcus Wire Group’s specifications, including annealing, pre-forming of wires and finished lay length, which significantly improves performance.

Electro bath polishing was used on the wire rope and floor and head tension plate brackets, while the spyders, rotules and compression posts were hand mirror polished.

In addition to the glass wall fixtures, other elements of stainless steel in the refurbished space included a staircase and handrail constructed by Arden Architectural Staircases and around 60 metres of 38mm grade 316 curved handrail fabricated and installed on an existing staircase by ASSDA Accredited Fabricator and Member Stainless Aesthetics.

Stainless Aesthetics Director Mike Mooney said his team also installed grade 316 capping on about 50 metres of 20mm glass balustrade, as well as further handrail and mirror-finish capping in the refurbishment of the resort’s health and fitness centre, which formed Stage 2 of the project.

With just 10 weeks to meet the venue’s fixed re-opening date of Stage 1, this challenging project required a high level of co-operation between trades and resulted in a classic marriage of form and function.

In a nod to the outstanding work carried out by all those involved, the RACV Royal Pines refurbishment was recently awarded the 2014 Queensland Master Builders Association’s Gold Coast Construction Award for Refurbishment/Renovation costing $5-$10 million.

This article is featured in Australian Stainless magazine issue 54, Spring 2014.

Local stainless companies get a piece of the mining action

1 May 2013

ASSDA member Australian Pickling & Passivation Service (APAPS) and ASSDA sponsor Sandvik Mining & Construction have been central to the expansion of a coal export port in North Queensland.

With Queensland coal exports forecast to increase to 250mtpa by 2015, the strength and durability of the state’s expanding coal transport infrastructure and rail systems is critical to ensuring export capacity.

This recent expansion required the manufacture of 300 three-piece conveyor frames using 40 tonnes of 316 grade stainless steel, specified to foil the port’s exposure to wind, rain, salt spray and abrasive dust.

Sandvik Mining & Construction manufactured the conveyor frames for the project, and APAPS pickled the frames before delivery to the terminal.

Stainless steel can corrode in service if there is contamination of the surface. Pickling involves the removal by chemical means of any high-temperature scale and any adjacent low chromium layer of metal from the surface of stainless steel.

The client requested that the stainless steel conveyor frames were pickled to achieve a product that would not rust. According to APAPS’s Director Richard Raper, ‘Pickling stainless steel removes all traces of burnt chromium caused by heat from welding and any iron contamination caused by handling and processing during fabrication.’ He added that several variables must be considered when pickling stainless steel, including the grade, surface finish, the size and shape of the structure and bath temperature.

Transported by road on B-double trucks from Mackay to the APAPS workshop in Newcastle, the conveyor frames arrived a dull grey colour and heavily soiled from anti-spatter and other contaminants. Pre-cleaning of the stainless steel was required prior to pickling as contamination on the surface can reduce the effect of pickling. The frames were sprayed using an Avesta 401 Cleaner and Callington Haven Brite Wash and left for 30 minutes before being high-pressure washed with hot water.

The immersion pickling method was used to pickle the conveyor frames. They were immersed in a nitric and hydrofluoric acid bath for approximately 1.5 hours, which APAPS’s own pickling technician determined following a number of inspections. Avesta Pickling Bath 302 was used at a temperature between 25-30°C. The frames were lifted from the bath and allowed to drain for 15 minutes before being washed down using high-pressure water.

APAPS’s pickling of the stainless steel by was central to ensuring the performance and durability of the conveyor frames and maximising their corrosion resistance. The treatment also produced a consistent and smooth finish with aesthetic appeal.

After the pickling treatment, the conveyor frames were strapped together in batches of five, with timber placed between the stainless steel and strapping. They were then transferred and loaded using a forklift with stainless steel slippers [covers] to protect the frames from cross-contamination. Due to the physical nature of the conveyor frames, only one layer of frames at a time could be placed on the truck deck, and these were tied down with web straps. Transportation took an average of 3 days between Newcastle and Mackay.

The project was completed in 10 weeks and delivered back to Mackay in stages. The APAPS team worked two shifts a day to complete the work on time for Sandvik.

Richard Raper says the project was a testament to APAPS’s membership of ASSDA, as it was the Association’s referral that won him the job.

‘This is a good showcase of how ASSDA members and Accredited fabricators can achieve great outcomes and how clients get what they expect when specifying stainless steel.’

Images courtesy of Australian Pickling & Passivation Service Pty Ltd.
This article is featured in Australian Stainless magazine issue 53, Autumn 2013.

200 series stainless steels - high manganese (CrMn)

1 May 2013

Almost 7 years after former Nickel Institute Director Dr David Jenkinson's 2006 Technical Bulletin, ASSDA's technical expert, Dr Graham Sussex, revisits the CrMn grades of stainless steel.

BACKGROUND
The majority of stainless steel is drawn from the austenitic family because these grades are readily formable, weldable and tough. These chromium-nickel (CrNi) and molybdenum-containing grades were traditionally grouped under the 300 series banner.

However, driven by the increased price of nickel several years ago, there has been renewed interest in lowering the nickel content of austenitic grades while maintaining the austenitic crystal structure. This is achieved by using combinations of higher manganese and nitrogen and even by adding copper.

These high manganese grades - 200 series austenitics - were first developed in the 1930s and were expanded during World War II because of a lack of domestic nickel supplies, especially in the USA.

Many of the new 200 series alloys have proprietary compositions that can vary with manufacturers’ processing. They are not classified or standardised under the ASTM/SAE three-digit codes.

FEATURES OF 200 SERIES
The mechanical, physical and forming properties of the CrMn and CrNi grades are very similar, although the CrMn grades generally have higher tensile strength because of higher nitrogen levels and a higher work-hardening rate because of the nickel level.

The conventional CrMn grades are used in hose clamps or lamp post clamps – thin material heavily cold worked for strength. Proprietary grades are used in galling-resistant applications such as bridge pins or in marine boat shafting, although duplex grades are a strong competitor. A disadvantage of CrMn grades is that the lower nickel content means a higher risk of delayed cracking after deep drawing.

A quirk of the conventional 200 series higher manganese grades is that they do not become magnetic when they are heavily cold worked, hence their suitability for use as end rings in electrical generators.

CORROSION RESISTANCE
The corrosion resistance of the newer CrMn grades is generally inferior to similar CrNi grades. To maintain the austenitic properties, the ferrite forming elements (chromium, molybdenum and silicon) must be in the correct proportions with the austenite formers (nickel, carbon, manganese, nitrogen and copper). If the strong austenite formers such as nickel are reduced, the corrosion-resisting, ferrite-forming elements must also decrease.

SENSITISATION
This occurs when chromium combines with carbon in the steel and forms micron-sized particles of chromium carbide so the chromium is unavailable to form the protective oxide film. The original 200 series increased the carbon level to remain austenitic (see Table 1), but this encouraged sensitisation during welding and is one reason that CrMn grades are not used for fabricated items.

Table 1: Registered 200-series grades

Grade Chemical composition (wt%)
AISI UNS Cr Ni Min N
304 S30400 18.0 - 20.0 8.0 - 10.5 2.0 max 0.10 max
201 S20100 16.0 - 18.0 3.5 - 5.5 5.5 - 7.5 0.25 max
202 S20200 17.0 - 19.0 4.0 - 6.0 7.5 - 10.0 0.25 max
205 S20500 16.5 - 18.0 1.0 - 1.75 14.0 - 15.5 0.32 - 0.40


DURABILITY
The newer grades, such as the Indian-developed J1 and J4 (see Table 2), are intended for use in milder environments. The low nickel content requires a reduction in the chromium content to about 15-16% compared to the 18% industry-standard 304. This is a significant reduction in corrosion resistance, especially for the very low nickel versions, and these small differences in chromium content can have a significant effect on durability.

Table 2: Grades J1 and J4

  Chemical composition (wt%)
Grade Cr Ni Mn N Cu
J1 14.5 - 15.5 4.0 - 4.2 7.0 -8.0 0.1 max 1.5 - 2.0
J4 15.0 - 16.0 0.8 - 1.2 8.5 - 10.0 0.2 max 1.5 - 2.0


The newer, low-nickel CrMn grades are successfully used in India, mainly for components such as cookware or mixing bowls that are formed rather than welded. The use of these grades has spread across South-East Asia and especially into China where the increase in capacity for 200 series production was about 3 million tonnes last year - or about 10% of the world’s production.

CONFUSION OF GRADES
The switch in use to CrMn grades (and not just the J1 and J4 grades) has continued despite lower nickel prices because of the perceived benefit of lower price. Unfortunately, the increased use of less corrosion-resistant grades has confused the industry as the CrMn grades are not magnetic and, at least initially, appear to be stainless and are often assumed to be 304 or even 316.

The confusion arose from decades of familiarity with magnetic, lower corrosion resistance ferritic grades such as 430 in contrast to the more corrosion-resistant and non-magnetic 304 or 316. In fact, magnetism has no relationship to corrosion resistance. Grade mix-ups have caused serious corrosion failures in industry and customer dissatisfaction due to less serious corrosion defects like tea staining. This has mainly occurred in Asia but also in Australia.

The variable impurity levels, particularly of sulphur and phosphorous, was a serious issue when there was a significant volume of the new CrMn grades produced by smaller, older mills. The increase in modern production facilities will proportionately reduce this risk. However, the metallurgical necessity to increase carbon levels for austenite stability in specific CrMn alloys means that welded fabrications still require thin sections or rapid cooling to limit sensitisation and the consequent increased corrosion risk.

IDENTIFYING GRADES
It is possible to distinguish between CrMn and CrNi grades by either portable and expensive X-ray fluorescence equipment or, more simply, by drop test kits to detect Mn (CrMn vs CrNi) or Mo (304 vs 316). The kits often use a filter paper and a battery to ensure the test will work rapidly even with cold metal. See ASSDA’s Technical FAQ No. 4 for further details.

QUALITY CONTROL

Users need to ensure they have good quality control systems to avoid installation of a low-level CrMn grade rather than the expected high-level austenitic. The relatively unknown conventional 200 series has a sophisticated niche. However, for cost reasons, clients may push to use the lower CrMn grades instead of the normal CrNi austenitics or, in sheet applications, the ferritics.

SCRAP AND SORTING GRADES
The fabrication scrap and end-of-life scrap from CrMn grades are not readily distinguished from conventional CrNi grade scrap. However, the value is substantially different as the nickel is still the most costly component. This has serious implications for the scrap industry because it is likely to reduce recycling and hence the sustainable and green image of stainless steel. Fabricators will find their total costs will require rejigging as the scrap from offcuts will have lower value, probably decreasing their profitability.

Each grade of stainless steel has its merits for different applications. However, it is vital to purchase from an educated and reputable supplier of quality materials in order to achieve the desired cost and quality outcome.

This technical article is featured in Australian Stainless magazine issue 53, Autumn 2013.

Stainless Liquid Architecture

1 May 2013

Stainless steel has transformed Perth's historic Forrest Place with a modern, interactive water sculpture.

The ‘Water Labyrinth’ was designed by internationally renowned artist, Jeppe Hein, and is his first permanent installation in Australia.

Launched in mid-November 2012, the $1.3 million sculpture is a major part of the Forrest Place redevelopment initiated by the City of Perth to create a stimulating public space for hundreds of thousands of residents and tourists.

Designed in a grid of nine squares, jets of recycled storm water shoot up into the air, creating 2.3m high water walls that randomly rise and fall. These water walls create up to nine ‘rooms’ that appear and disappear in sequences of 10 seconds before changing configuration.

Visitors of all ages leap from room to room or simply have a splash. The Water Labyrinth enables the interaction of people and art while utilising an important public space flanked by the sandstone inter-war Beaux-Arts style General Post Office and Commonwealth Bank buildings designed by John Smith Murdoch.

Hein says interaction is a distinctive element of the artwork and people play a vital role. ‘The Water Labyrinth activates the space and invites the public to make use of the artwork, either as a space for seclusion and relaxation or the opposite, a place for pure joy and playfulness.’

An impressive feature of the 12m x 12m Water Labyrinth is the 179m of stainless steel grating and drainage. As one of Australia’s largest manufacturers of stainless steel wedge wire grating, ASSDA member and Accredited Fabricator Paige Stainless was chosen to fabricate the water sculpture.

The popular water sculpture features approximately 62m2 of PAIGE STAINLESS HEELGUARD® wedge wire and approximately 160m of 30x5mm flat bar in 304-grade stainless steel, supplied by ASSDA Sponsors Atlas Steels and Fagersta Steels.

PAIGE STAINLESS HEELGUARD® wedge wire is at the cutting edge of water drainage technology, overcoming inherent problems of drainage. The purpose-designed wedge shape in the stainless steel grates allows high volumes of water to shoot through the grates while trapping waste material for easy removal and cleaning.

The grating systems were custom made for the Water Labyrinth with a 5mm gap size and a 4mm wire head width, allowing a 50% open area for water flow. Pickling and passivation treatments were performed on the stainless steel grates prior to installation.

Paige Stainless senior design consultant Daniel Manning said a fine toothcomb approach was taken to ensure there were no safety issues in the final structure, as most visitors would be bare foot when experiencing the Water Labyrinth.

Having worked with stainless steel for over 15 years, Hein says stainless steel was the only material offering the required durability and compatibility for chemical treatment necessary for installation. Manning added that stainless steel’s aesthetic and corrosion resistant properties also made it an easy choice for materials specification in water technology.

Manning coordinated the production of the drainage system, which is an essential component of the Water Labyrinth’s design. All stainless steel components of the sculpture were 100% fabricated at Paige Stainless’s workshop in Caboolture, Queensland.

‘The collaboration with Paige Stainless flew smoothly and was very professional,’ says Hein. ‘They were able to produce and deliver quickly and the grids fabricated were of an extremely high quality.’

Main image above courtesy: Johann König, Berlin and 303 Gallery, New York. Photo credits: Jeppe Hein.
This article is featured in issue 53 of Australian Stainless magazine, Autumn 2013.

Quality Shines

1 May 2013

In the beleaguered Australian manufacturing sector, it's heartening to find ASSDA member Tasman Sinkware is a world-class leader in innovative design and manufacturing. Better still, in addition to supplying the domestic market, Tasman is exporting its products to Canada, the United States, New Zealand, Hong Kong and Singapore.

Tasman began operations in 1948 as a domestic metal fabricator in Adelaide. A move to sink manufacture saw its Oliveri brand pioneer the deep draw process in Australia and introduce precision manufacturing technology to produce high volume sinks.

Sixty-five years later, Tasman is now Australia’s only world-class, production line sink manufacturer, and its premium Oliveri brand is a market leader with a reputation for excellence in design, function and durability.

All Oliveri sinks are manufactured at Tasman Sinkware’s facility in Adelaide from 18/10 304-grade stainless steel supplied by various Australian distributors from reputable overseas mills. Significant capital expenditure over the years has enabled the company to introduce state-of-the-art processing equipment, including pressing, resistance welding, grinding, polishing, cleaning and product assembly equipment, most of which incorporate automation and/or robotic technology.

Tasman Sinkware employs a two-piece manufacturing process. The drainer and bowls are pressed separately then welded together to create bowls that are deep and have straight sides to ensure maximum capacity.

As a result, its stainless steel kitchen and laundry sinks are considered amongst the best in the world and the development of tapware and innovative accessories such as colanders and cutting boards has helped deepen domestic and international market penetration.

The superior design and function of the Oliveri sink range is led by Tasman’s in-house design team in Adelaide. Boasting more than 12 sink ranges and complementary accessories, the Oliveri brand has a strong presence in the building industry with the ability to influence trends.

Tasman Sinkware supplies leading Australian plumbing and electrical merchants and is developing inroads to commercial and residential real estate developments. Oliveri products are sold and distributed overseas through local agents and Tasman Sinkware also has staff on the ground in the USA.

Competition from cheaper Chinese imports is counteracted by Tasman Sinkware’s continued commitment to providing the highest quality products and excellent customer service. Manufucturing manager Steve Warnett says Tasman continues to innovate with new, leading-edge designs for the renovation and building markets. The Oliveri brand also enjoys high market recognition and loyalty amongst consumers and retail outlets.

Stainless steel continues to be the material of choice in laundries and kitchens due to durability, heat resistance, visual appeal and its 100% recyclability.

Grade 304 stainless steel has excellent corrosion properties, is resistant to most food processing environments and organic chemicals, and can be readily cleaned. It also has good oxidisation resistance in intermittent service to 870°C, and in continuous service to 925°C, making grade 304 the most ideal stainless steel grade and material for heat resistance in kitchen accessories.

Tasman Sinkware is Quality Accredited to ISO 9001. All Oliveri sinks are engineered to world standards and manufactured to AS 1756 and laundry tubs are manufactured to AS 1229.

www.oliverisinks.com

Images courtesy of Tasman Sinkware.
This article is featured in Australian Stainless magazine issue 53, Autumn 2013.