Stainless steel is playing an important role in delivering effective infrastructure to achieve water savings, securing a sustainable environment and future for irrigation communities in Australia.

Murray Irrigation's Private Irrigation Infrastructure Operator Program (PIIOP) Round 3 in New South Wales is a modernisation project focused on upgrading larger infrastructure within the main canals of its irrigation assets, including Mulwala and Wakool Canals.

Mulwala Canal is Australia’s largest irrigation canal, and together with Wakool Canal runs 157km long. It has the capacity to deliver more than 1,500,000ML of water per year to irrigators in the Southern Riverina, helping to generate more than $500 million of gross agriculture revenue per year for the region. 

ASSDA Member AWMA successfully delivered 91 stainless steel water control gates across the project’s irrigation system assets. This modernisation program has substantially increased water efficiencies, improved water flow, enabled ordering flexibility and significantly reduced water leakage through infrastructure upgrades.

The works included 21 Mulwala Canal Sites (65 LayFlat gates and 26 Undershot gates), Lawson Syphons (two Undershot gates), the Edward River Escape (two Bulkhead gates) and the Wakool Canal Offtake (three Undershot gates).

All gates were purpose-engineered, designed and manufactured by AWMA to meet exact site and operational requirements. The water control gates measure up to 5.5m wide and 3m high in size, fabricated from 230 tonnes of stainless steel. The stainless steel water control gates required 7.5km of weld, then pickled to improve corrosion resistance and tested in-house to international ISO 9001 quality standards. Dedicated tooling and handling equipment were also paramount in ensuring no cross contamination during all processes undertaken.

ASSDA Member Vulcan Stainless supplied grade 304 stainless steel plate material, whilst ASSDA member Valbruna Australia supplied grade 431 stainless steel shafts.  

ASSDA Member Akras Industries were also engaged in a semi-automated welding process in order to join the oversize gates back together post laser cutting and pre-pressing. Welding was carried out in line with AS1554.6 / ASME 9 /AS1210 - Class 1 classifications to ensure the highest weld integrity and compliance to quite rigid specifications as set out within the scope.

Another ASSDA Member Arcus Wire Group were engaged by AWMA to assist in the design and supply of 20mm, 7x19, grade 304 stainless steel wire rope cables for the purposes of raising and lowering the water control gates. 130 cables were supplied (two cables installed per LayFlat gate), with an individual Minimum Breaking Strength (MBS) of over 27,000kgf. Arcus Wire Group and AWMA collaboratively designed the bespoke cable end terminations to suit the specified MBS, and the manufacture of these products were completed in-house by Arcus Wire Group. 

Stainless steel was specified for its longevity and durability, particularly with the water control gates being submerged in irrigation water. In addition, stainless steel was chosen over aluminium in the materials specification to extend the nominated asset life from 25 years to 50 plus years. The gates have been integral to improving the efficiency and productivity of water delivery, and the use of stainless steel offers an economically maintainable and longer lasting infrastructure solution.

All new gates installed are stainless steel and telemetry-enabled for remote control, a capability that has radically changed the way Murray Irrigation manages water delivery to its customers. 

Photo banner at top of article courtesy of Ertech. 
Photo above (left) courtesy of Murray Irrigation. Photo above (right) courtesy of AWMA.

This article is featured in Australian Stainless Magazine issue 65, 2019.

A new luxury home renovation in Cottesloe, Western Australia is leading the way in cutting-edge bathroom design with a statement stainless steel wall.

ASSDA Member and Accredited Fabricator ALLOY’s stainless steel mosaic tiles are featured in the bathroom designed by Nina Dempster of Ozbyrd Design and architect Paul Jones RBA of a recently constructed addition by builder Adrian Zorzi.

The alluring back wall of the walk-in shower is lined with ALLOY’s “SWISS CROSS” 30x30mm stainless steel mosaic tiles. The mixture of the No. 4 and No. 8 brushed and mirror finish 304-grade solid tiles offers a textured finish with a glimmering light reflection and decorative appeal.

The client wanted a brilliant surface finish to enhance the space and grandeur, particularly with no natural light feeding into the area. Stainless steel delivers the brief, with its reflective sheen and the added benefits of the material’s hygienic properties and durable nature. It also plays an important aesthetic role in the camouflage of water spots. 

The entire shape of ALLOY’s mosaic tile has a unique bevelled edge, and its manufacture from 1.6mm thick sheet ensures the tile will not dent, crack or de-laminate. No surface treatment was required on the stainless steel, being installed in an indoor environment.

The end result is a high quality, precision-engineered stainless steel product striking a balance between function and luxury style.

Photo credit: Ryan North, and are subject to copyright.

This article is featured in Australian Stainless Magazine issue 65, 2019.

When Mark Ellis, a warehouse operations clerk for Atlas Steels, suffered a serious leg injury that resulted from an incident at its Ingleburn Service Centre, the business vowed it wanted to prevent this type of incident from reoccurring.

"It shook the business," says Regional Director, John Pearson. "It was a terrible thing for Mark, his family and for all of our employees. You could see and feel the devastation."

Ellis was injured when he stepped back and collided with a multi-directional sideloader forklift. Atlas’s quest to enhance safety saw the business introduce a number of measures across its operations. Other businesses working to prevent serious incidents can learn a lot from this example, particularly the important role of employees in coming up with ideas to improve workplace safety.  

“The effect of this incident on all was dreadful”, says National SEQ Manager, Maree Mihaljevic. “We are extremely focused on engaging our people and strengthening our safety system and processes.”  

A practical response

Atlas’s response to this incident included a series of practical measures. Service Centre Manager, Marc McAllister, says Atlas introduced an improved Traffic Management Plan and controls in consultation with its employees. One of the most important changes has been the introduction of a pedestrian awareness tool (PAT), a base plate that has a pole with a strobe light on top. If a pedestrian stops to work in an aisle they must place PAT in front of the aisle, or at a safe distance from them, and turn the light on. The light is at eye level with the sideloader forklift operator and provides additional visual awareness to the operator who must not enter beyond the point of PAT placement. As PAT is portable it can be used in a variety of locations.  

The business has also increased training, particularly around traffic management and sideloader forklift operation, with an online interactive training system being built from the ground up and employees being put through refresher courses.  

The way we do things around here

Consultation was conducted across the country resulting in the development of a Safety Charter that depicts a ‘Safety First’ approach and the agreed minimum safety expectations for all employees, supervisors and managers with signed ownership it is prominently displayed at each site.  

Ellis has conducted a series of presentations to his workmates and to the wider steel distribution industry that Mihaljevic, says “Demonstrated that this was real, not just an anonymous report or statistic but a worker who has a name and family. It highlighted his journey, the injury impact on others and the importance of working together in implementing and maintaining safety systems and processes with the presentation correlating with Mark’s passion for golf.”  

After the incident McAllister gained a forklift licence himself so he would have experience first-hand. “I try and regularly get out there and work with them,” he says. “I get to see the challenges they face, and we work through to improve. It also helps in strengthening our team.”   

A continuous quest

After his incident, Mark Ellis has made a successful return to work; but the effects of his incident at Atlas Steels are long lasting. It has driven a quest to elevate safety so that no one suffers a similar incident. 

Mihaljevic says Atlas’s efforts to improve safety are ongoing. “It’s relentless,” she says. “The importance of having well risk assessed safety systems and processes in place especially where mobile plant is in use is evident.”   

There are learnings for everyone where mobile plant is in use says Pearson, “If you walk or drive into any workplace, follow the signs and directions of the employees and maintain situational awareness to ensure your own safety and the safety of others.”

Pearson adds other businesses can provide ideas that can be trialled and possibly implemented. He says it’s a never-ending search for improved risk management across the board to reduce the potential for injury.  

But Mihaljevic says don’t disregard incidents that occur in other businesses. “If you read something that happened in another company, don’t just think ‘that’s horrible’, act on it. Ask yourself if that incident or similar could happen in your business and what do you have to do to control that risk.”  

Good safety leadership is paramount and its important to lead by example McAllister says. “Continue to engage and encourage open conversations regarding safety. Some of the best ideas will come from the warehouse floor.”

Atlas Steels acknowledges that this article was produced as a result of a SafeWork NSW Enforceable Undertaking.

This article is featured in Australian Stainless Magazine issue 65, 2019.

What is the fire rating of stainless steel? This is a common enquiry from ASSDA Members and the construction industry, especially with the current concerns about flammable cladding. The three major branches to this question are covered in this article.

Will stainless steel burn, and if it does, will it give off fumes or facilitate the spread of fire?  

This question is readily answered because stainless steels are steels. It is recognised that steels do not burn and only start to melt at about 1400^oC. This means that stainless steels do not have a “fire rating” as such, so the tests of AS/NZS 1530.3 (or the equivalent tests in BS 476) are not required.

Heating in a fire will obviously have an appearance effect because, unlike the transparent nanometer-thick passive layer formed in moist air, stainless steels heated above about 300^oC in air discolour as they grow a less dense oxide layer. This develops from the rainbow colours seen beside welds to a dark and non-protective oxide layer whose thickness depends on the time of exposure and temperature reached. The street rubbish bin shown suffered from a fire but remained functional for almost a year (until the repair cycle reached it) with a decorative rainbow oxide. By way of comparison, powder coated bins would suffer from unsightly burn marks and corrosion. 

For austenitic alloys such as 304 and 316, the temperature limits for lifetime section loss due to oxidation is about 870^oC (with temperature cycling) so they are routinely used in high temperature furnaces and ductwork. The current trend to apply decorative coatings to stainless steels would require an assessment to determine the combustibility, potential fumes and flame spread of the coating. Tests to AS/NZS 1530.3 would be appropriate. 

Microstructural effects of a short-term heat cycle (less than a couple of hours of exposure, such as a fire) could include carbide precipitation (sensitisation) in an austenitic alloy which was not an L grade (i.e. carbon >0.03%). Duplex and weldable ferritic grades should not have sufficient carbon for sensitisation. Sensitisation would degrade the corrosion resistance but not affect mechanical properties. Both duplex and ferritic grades can suffer 475^oC embrittlement, however data produced by the International Molybdenum Association (IMOA) shows that this requires more than two hours in the 400^oC to 500^oC range for a 50% reduction in toughness. This duration is unlikely in most fires.

Will stainless steel provide a barrier to flames and if it does, how rapidly will the heat penetrate the barrier sufficiently to cause damage (usually a specific temperature rise) on the far side? 

A satisfactory demonstration is supplied by reference BS 647 Part 22 tests carried out for a British Stainless Steel Association (BSSA) member, Stewart Fraser, who manufacture 316 framed doors which include a cavity filled with non-combustable boards. The results are given at www.bssa.org.uk/topics.php?article=106.

It showed slight discolouration and distortion on the flame impingement side with the sheltered side of the door reaching only 98^oC after 60 minutes. The test was continued for another 80 minutes without the failure of flame containment or subsequent opening of the door in its frame. Similar testing was carried out on a 1.5mm thick 2304 duplex sheet fabricated into a simulated ship’s bulkhead with enclosed ceramic wool insulation. With a bright orange glow of an 1100^oC metal temperature on the flame side, the “safe” side reached 30^oC after 40 minutes and 110^oC after 60 minutes. The test was terminated after 120 minutes with containment still satisfying IMO resolution A518 (XIII).

What are the effects (both during and after an event) to the mechanical properties of stainless steel? How do these compare with structural carbon steels? 

There are tests as well as a theoretical basis which demonstrate that both austenitic and duplex stainless steels have superior high temperature properties compared to carbon steel. The table below shows the deflection and failure modes of three metre long commercial electrical cable trays loaded to simulate actual loadings. They were heated with 18 LPG burners to obtain an average temperature of 1000^oC  to 1050^oC for at least five minutes. [Nickel Institute publication No. 10042]

The publication also considers the life cycle costs (LCC) of the use of aluminium, galvanised steel or stainless steel for stairways, handrails, gratings and firewalls, as well as cladding for corridors and accommodation modules on North Sea platforms. Fire risk controls are obviously a major concern although corrosion resistance is also critical. On an LCC basis, stainless steel was most economical especially when its reduced requirement for maintenance periods were included. 

In addition to the above testing in cable tray applications, substantial research and application work has since been carried out and codified. Installations include 2205 duplex hangers suspending the slab which forms the floor of the emergency ventilation duct in the CLEM7 tunnel in Brisbane [ISSF].

In short term fires such as on balconies or stairways, the temperature rise exposed to an ISO 834 fire temperature profile depends on thickness and emissivity. Polished stainless steels typically have low emissivity of <0.1 and hence a slower temperature rise. Conservatively, after 30 minutes a 12mm sheet of stainless steel with 0.2 emissivity would reach 620^oC whereas steel (with no rust) and 0.4 emissivity would reach 750^oC.   

When considering strength and deflection, the metal temperatures in a conventional fire do not reach levels to anneal the material so any cold work strengthening will raise the temperature for a 50% strength reduction. In addition, as shown in the graph, the reduction in Young’s Modulus, i.e. deflection from a specific load, is less than that of carbon steel for temperatures above ~200^oC. By 600^oC the modulus retention for stainless steel is 0.75 compared to 0.3 for carbon steel, i.e. less than half the deflection for a given load.

In summary, stainless steel has substantial advantages in structural use when fire risk is considered, and these advantages continue into higher strength and lower deflections at elevated temperatures.

CLEM7 image above courtesy of Ancon.

This article is featured in Australian Stainless Magazine issue 65, 2019.

Stainless steel is the ultimate materials solution for electrical enclosures in safeguarding the network and communications technology invested in underground mining sites.

Olympic Dam is a large polymetallic underground mine located in South Australia, approximately 550km northwest of Adelaide.

Home to a major source of oxide copper gold deposit, Olympic Dam produces combined quantities of copper, gold, uranium and silver through an underground mining system integrated with a metallurgical processing plant. The large deposit was discovered in 1975 and in 1988, the mine was opened by WMC Resources. Today, Olympic Dam is owned and operated by BHP, following its acquisition of WMC Resources in 2005. 

ASSDA Member and Accredited Fabricator B&R Enclosures was contracted by MPS Building & Electrical to assist with finding a solution to a fibre enclosure hub capable of linking four mining shafts to the surface.

B&R’s design and engineering team worked closely with MPS Building & Electrical to design and fabricate an enclosure specific to BHP’s requirements. The customised solution was supplied through Auslec Electrical and Data located in Wingfield.

The outcome was a double door stainless steel field cabinet, 1000mm deep and capable of housing electrical and monitoring equipment. Due to the remote location of the project and the type of equipment installed, stainless steel sunshades and lockable handles were included to reduce heat within the enclosure and prevent vandalism.

Grade 316 stainless steel with a No. 4 surface finish was specified for the custom-designed enclosures, with material supplied by ASSDA Member Outokumpu in 1.5mm thick sheet. 

Underground communication networks are a critical link between operations below ground and at the surface to ensure efficiencies in production and personnel safety. Protecting the equipment that delivers these communication networks is vital and stainless steel offers the durability and longevity required to deliver a robust structure to ensure preservation of the internal hardware.

In addition, grade 316 stainless steel offers excellent corrosion resistance, particularly to pitting corrosion which can occur in inland Australia due to high salinity in the ground water. 

B&R have worked alongside BHP and MPS Building & Electrical on past projects, installing enclosure solutions into a variety of different applications. B&R’s ability to design custom solutions along with their reliable service meant MPS Building & Electrical could confidently deliver this project and supply an enclosure suitable for harsh mining environments and extreme weather conditions.

As a result of good collaboration and local technical expertise, the project’s stainless steel enclosure design is now a standard specification for future installations across Olympic Dam.

This article featured in Australian Stainless magazine - Issue 64, Summer 2018/19.

Mirror finished stainless steel sign blades can be found scattered along the central boulevard of Sydney’s revitalised Darling Harbour.

Through a recent $3.4 billion transformation, Darling Harbour has become Australia’s largest entertainment and events precinct boasting world class facilities, including over 40,000 square metres of exhibition space. This urban rejuvenation builds on the success of Darling Harbour and in turn, will generate $200 million annually in economic benefit for the NSW economy.

The Harbour is ringed by attractions, entertainment and extraordinary waterfront restaurants. The Boulevard creates an active north-south pedestrian connection between Central Station and Cockle Bay. Its prime location is within walking distance of most points in the Sydney CBD therefore wayfinding signage is pivotal in navigating people through and around the precinct.

ASSDA Member and Accredited Fabricator Stoddart were engaged by Lend Lease to manufacture and install 19 stainless steel wayfinding sign blades for Darling Harbour’s ‘once in a generation’ re-development. The sign blades are featured in groups of two and three, each standing seven metres tall and two metres wide.

258 panels of grade 316 stainless steel were used for the sign blades in order to provide housing for LED display screens throughout the precinct. The structural stainless steel frame also mounts speakers and power outlets. All stainless steel used in this project was supplied by ASSDA Member, Fagersta Steels. 

Featuring a mirror profile finish, the stainless steel signs create a stunning visual effect through the reflection of the countless city lights and surrounds of the bustling tourist and entertainment mecca.

Stainless steel was specified by landscape architects, Hassell, for its aesthetic appeal and high-quality attributes. The Harbour’s salt water environment and location was also a consideration in the materials specification, being adjacent to the city centre.

It is only fitting for quality material such as stainless steel to be showcased in one of the world’s most desirable entertainment and event destinations.

This article featured in Australian Stainless magazine - Issue 64, Summer 2018/19.

One of the most common misunderstandings in specifications for stainless steel fabrication relates to the post-fabrication treatments to restore or enhance the corrosion resistance. 

The surface treatment processes invoked vary between pickle and passivate, passivate, or sometimes simply pickle. Needless to say, whilst pickling and passivation are two distinct processes, a lack of clarity can cause some confusion between the owner and the builder/fabricator about what is expected and required. 

This article briefly outlines the factors that affect the corrosion resistance of stainless steels, what surface treatments can be used and how they affect the steel’s surface to improve corrosion resistance.

Corrosion Resistance and its Controls

Stainless steel is resistant to aggressive environments because of a very thin, self-repairing, chromium-rich complex, oxide film present on the surface of the steel. It is not completely impervious, but it dissolves many orders of magnitude more slowly than it reforms. The passive layer is more resistant for alloys with more chromium, molybdenum and nitrogen. This is the reason for the empirical, composition based Pitting Resistant Equivalent (PRE(N)) index which is often used as a ranking tool in selecting which stainless steel will be used in new applications. However, the alloy composition is not the only control of the passive film’s strength, and hence its corrosion resistance. There must also be an adequate supply of oxygen and moisture to maintain the integrity of the passive film. This requires either good design or a maintenance program – and preferably both.  

For a specific alloy, i.e. a specific PRE(N), the passive film (and hence the corrosion resistance) can be improved by chemically oxidising the steel’s surface. Air and water are good and the ASTM standard dealing with passivation (A967 Standard Practice for Chemical Passivation Treatments for Stainless Steel Parts) advises that for many environments, no further treatment is required for satisfactory service. However, oxidising or chelating chemical treatments will provide better corrosion resistance.

Roughness

Corrosion resistance is indirectly improved if the surface is smooth and clean (free of contaminants) to facilitate the self-renewal of the passive film. For abraded surfaces there is also a critical surface roughness of 0.5μm Ra that should not be exceeded. This is recognised in surface finish 2K in EN 10088.2. It seems that for steels, the size of abrasives causing this roughness is too large to cut the surface cleanly and leaves rough edges and metal debris which can accumulate dirt and corrosives – hence more rapid corrosion with coarser polishing.

Contamination

The bête noir of stainless steel: carbon steel contamination. If it is not removed, the stainless steel will rust. In marine environments, it will collect chlorides and cause large rust stains and small pits in the stainless steel. If it is mechanically removed, it is likely that the smeared steel will leave a larger rust stain, although it may be less intense. Acid treatments can remove carbon steel deposits and have the added advantage that they can also remove surface breaking manganese sulphide (MnS) inclusions. These MnS inclusions do not have a passive film and act as initiating points for corrosion.

Welding

If you have welded your fabrication and there are rainbow coloured bands along the welds, they are zones where the passive film has been destroyed. Under the darker colours, there will be a wedge-shaped layer with a lower chromium content than the bulk stainless steel. Corrosion will initiate in these coloured bands. The weld tint colours can be mechanically removed provided the grinding is not too rough. Chemical removal by pickling is often a better option.

Pickling

Pickling uses a mixture of nitric and hydrofluoric (HF) acids. The wide range of concentrations and exposure times are described in ASTM A380 Standard Practice for Cleaning, Descaling and Passivation of Stainless Steel Parts, Equipment and Systems. Typically the nitric concentration is up to 10 times the HF concentration, but pickling is slow unless the HF is more than about 3%. Longer pickling times are required at lower temperatures or if a high alloy is being used, i.e. super duplex takes longer than duplex which requires longer than 304. If a paste is used, the contact area acid gets exhausted unless it is stirred, e.g. with the application brush. Thorough washing is needed to remove all residue even from crevices and, to avoid stains, it is important not to allow acid or rinse water to dry on the surfaces.  

OHS and environmental considerations mean that using a pickling contractor is easier, safer and ensures the appropriate disposal of acid and pickled heavy metals. Contractors will often use a temperature-controlled, stirred tank or, sometimes, a spray pickling solution in an acid-proof and bunded bay. Unless an additional level of passivation is required for a very aggressive environment, the outcome is a pickled item that is passive.

Chemical Passivation

The traditional and very effective acid is nitric, typically between 15% and 25% for about two hours, although it is not uncommon to drop machined parts into a bucket of nitric acid for half a shift. The passive film is significantly strengthened and the ratio of chromium to iron in the surface layers can exceed 1 – compared to <0.4 in the bulk. Nitric acid will also remove rust stains and sulphide inclusions plus, more slowly, carbon steel smears. Phosphoric acid will remove rust and sulphide inclusions, but it is not oxidising and will not strengthen the passive film. Another method of strengthening the passive film of a chemically-clean surface is to use a hydrogen peroxide solution – lots of free oxygen and only water residue.

There are other acids that will strengthen the passive film and dissolve carbon steel and inclusions, but by a different method. Citric and oxalic acids and EDTA all have a carboxylic acid [O-C-OH] atomic structure, and once the acid dissolves the unwanted metal, the positive ion is trapped by the negative oxygen atoms in a process called chelating or sequestering. This process is used in wastewater treatment to remove metals. In passivation, it is important to rinse thoroughly. Chelating treatments are widely used in the food industry as formulations which include biocides, so the citric acid does not contribute as a food source.

There are a number of special cases detailed in ASTM A380 which require care when pickling:

• Sensitised or hardened (nitrided or carburised) areas may suffer intergranular attack.

• Free machining stainless steels requires an inhibitor or it will pit.

• Martensitic stainless steels can suffer hydrogen embrittlement.

All of the above methods are chemical treatments which are quite traditional and generally well applied. Further information is provided in ASTM A380, which also details test and inspection methods to confirm surface cleanliness.

Three Definitions

CLEANING Removal of contaminants such as soil, grease, oil, etc. using low-chloride detergents and/or solvents to allow free access for water and oxygen to grow the passive film.

The bulk material is not affected and the surface looks brighter. Chlorinated solvents may be a risk as residues can degrade if heated and may cause pitting. In vessels or pipework, it is important to drain and dry the surfaces.

PICKLING The removal of any high temperature scale and any adjacent low chromium layer of metal from the surface of stainless steel by chemical means.

It also removes embedded or smeared carbon steel, inclusions and loose flakes of stainless steel left from abrasives.

It will leave a matt finish, which may be paler if the pickling is extended. It provides a passive surface immediately on rinsing – hence you pickle and get a passive surface.

PASSIVATION The treatment of the surface of stainless steel, often with acid solutions (or gels), to remove contaminants and promote the formation of the passive film on a surface that was freshly created, e.g. through grinding, machining or mechanical damage. It will remove acid soluble inclusions such as MnS.

Clean humid air will form a passive film on clean stainless steel and the appearance will not change.

Chemical passivation strengthens the passive film and typically takes an hour or so at ambient temperatures. Air passivation is adequate unless the environment is very aggressive for the grade.

1. Rusting steel contamination from shearing stainless sheet. Photo courtesy of Graham Sussex.	2. Rainbow oxide from poor gas shielding during welding. Photo courtesy of HERA.
3.Before (left) and after (right) pickling of welded fitting. Photo courtesy of Graham Sussex.	4. Welded components after pickling to remove heat tint and possible steel contamination. Photo courtesy of Australian Pickling & Passivation Service.

This article featured in Australian Stainless magazine - Issue 64, Summer 2018/19.

Exemplary stainless steel craftmanship has delivered a sophisticated and lavish cocktail lounge in the heart of the Gold Coast’s entertainment hub.

Cocktail connoisseurs have been flocking to Cherry, The Star Gold Coast to experience the designer drinks on offer in the grandeur of the lounge featuring a 22m long bar. Refurbished in 2017 as part of the first stage of the property’s major transformation, its upmarket look and feel was inspired by its sister venue at The Star Sydney.

Central to Cherry’s luxury design is the intricate, gold metalwork featured in the VIP booth screens, lounge surrounds and balustrades. ASSDA Member and Accredited Fabricator Minnis & Samson fabricated these elements using grade 316 stainless steel tube and flat bar supplied by ASSDA Member Australian Stainless Distributors. 

The stainless steel was mirror polished prior to the electrostatic application of a special coating to achieve the gold colour finish. Crystal hardware and lush red velvet furnishings complement the gold stainless steel to deliver the opulent design and vision of the cocktail lounge.

Stainless steel is a high quality and high strength material, and was specified for its longevity, hygienic properties and aesthetic appeal. In addition, stainless steel offered better weldability to achieve the detail in the metalwork’s curvature design.

This article featured in Australian Stainless magazine - Issue 63, Spring 2018

A stainless steel masterpiece

Michael Van Dam’s award-winning stainless steel dragon sculpture plays a major part in Chinese culture dating several thousand years. 

The dragon is a symbol of prosperity, strength, courage and resolve. The designer himself was born in the year of the Dragon (1964). As a result of welding thousands of stainless steel links together, alongside Van Dam’s creativity, a durable and aesthetically pleasing piece of art came to life – The ‘Emerging Dragon’. 

The Emerging Dragon has been showcased at various locations and shows on the Gold Coast. This stainless steel masterpiece was originally created for the 2015 Swell Sculpture Festival held on Currumbin Beach which attracted 250,000 visitors over ten days, winning both Kid’s and People’s Choice Awards. 

The 3m high by 5m long sculpture was created from more than 4000m of 4mm 316 stainless steel chain and weighs an impressive 700kg. Following fabrication the sculpture was electropolished. All stainless steel chain used for Michael’s sculptures is supplied by ASSDA Member BRIDCO. 

Van Dam’s stainless steel art pieces are well equipped to face the rigours of outdoor display. This led to grade 316 stainless steel chain being his choice of material for all his sculptures. He believes the use of stainless steel for his pieces makes for a unique use of the material, it feels great to the touch, can withstand various environments and will outlast most other materials. 

This article featured in Australian Stainless magazine - Issue 63, Spring 2018

Humanity’s use of materials has progressed over the millennia from natural resources such as plants and stone to manufactured materials such as ceramics, metals and plastics with a corresponding increase in consumption of energy and materials – and increasing waste production. In parallel, the world’s consumers have grown exponentially from about 1 billion in 1800, to 7.6 billion in 2018 and a predicted 9.8 billion in 2050 – all demanding more infrastructure, facilities and resources to support the expectations of higher standards of living. This has led to an increasing realisation that green production, recycling, waste reduction and more efficient use of resources are essential.  

The green or sustainable credentials of stainless steels largely derive from their corrosion resistance and consequent long life, without the need for more than cleaning by rain washing or routine water and detergent cleaning. A good example is the Chrysler Building in New York which was built in 1930. It has only been washed twice in 1961 and 1995 using low impact detergents and yet it still retains its bright appearance partly because of good drainable design, although the inherently smooth surface from its manufacture was also a factor.

In comparison, the Eiffel Tower in Paris is painted every seven years using 60 tonnes of paint in a 15-month campaign with 25 painters and their consumable equipment. Closer to home, the constant repainting of the Sydney Harbour Bridge provides a similar contrast to the penetration of stainless steel into the building and construction industry without the ongoing labour required for repainting and maintenance of carbon steel structures. At a smaller scale, current practice minimises maintenance in more aggressive environments by processing the surface after fabrication as shown by the bright surface of the electropolished railings beside the Brisbane River.

It is difficult to compare any corrosion (and therefore lifetime) of stainless steel with carbon steel or zinc because of the different mode of attack, i.e. stainless steel pitting vs. the general loss of copper or zinc. However, a South African 20-year atmospheric corrosion study of lifetimes used carbon steel as a baseline of 1 and found that zinc, copper, aluminium and 316 stainless steel had lifetimes of 25, 90, 170 and >5000 years respectively. 

A secondary benefit of the long life of stainless steel is that the carbon dioxide emissions and the embodied energy required in manufacture are amortised over a much longer period of time. Raw CO2/kg metal and MegaJoule/kg metal data is given in Table 1 for these materials. Stainless steel is not the lowest or highest in absolute terms of carbon dioxide emissions or energy required per kilogram of stainless steel produced, but when its long life is considered, its performance on these criteria is outstanding.

Stainless steel does not use volatile organic solvents in its production or use and does not contain lead, mercury or other leachable heavy metals. Stainless steel is routinely used in pharmaceutical, food and beverage processing because of this chemical stability due to the hydrated chromium-oxide passive layer.

In a confirmation study of the stability of stainless steel with water, a 3.5-year testing program of the hot and cold water in 316 pipework of a Scottish hospital found the chromium content was less than 1% of the 0.5ppb permitted for potable water and nickel content (a trace food requirement) was less than 3% of the 0.2ppb permitted.Looking at environmental issues, Table 2 shows the results of a Scandinavian run-off study, commissioned because of concerns about heavy metals in environmentally sensitive areas. The zinc and copper values will obviously vary with time as the oxide layers form and leach. However, the passive film of stainless steel is substantially stable so that run-off can be used for potable water. A first flush discard system may also be used.

REUSE AND RECYCLING

In a well designed and executed project, stainless steel will not degrade and therefore it is probable that the process or application will become outdated while the stainless steel is still operational as a pipe or vessel or tank or other component. Such repurposing may be on the same site or elsewhere in the same industry, e.g. from milk to wine or water or fruit juices or for a radically different process. However, it is rare for repurposing to move from chemical to hygienic industries. Since stainless steel has an inherently high value, there are multiple examples of building refurbishment where the stainless steel has suffered mechanical damage or the layout must be changed. The William Penn Place (Pittsburgh) rejuvenation shown was after 50 years of use but did not require material replacement.

Recycling may occur as part of the life cycle, e.g. re-melting of scrap, or at end-of-life. Table 3 indicates significant variations depending on the material and its proposed use.  A study of the recycling at 14 European mills covered 18 products across two ferritic, two austenitic and one duplex grade, i.e. all but the small volume of specialised, niche grades of stainless steel. For each of the 18 products, the mean recycled stainless steel content was significantly greater than 65%. The six ferritic products were all above 90%, the nine austenitic products were between 68% and 78% while the three duplex product forms had between 69% and 76% recycled steel input.

While some mills show significantly higher percentages, a nominal 30-year life of stainless steel combined with the almost 6% compound growth of stainless steel use means there is insufficient scrap available now to substantially increase the recycled content from general use.

LIFE CYCLE COSTING AND SAVINGS FROM DURABILITY 

The minimal maintenance required on stainless steel buildings and structures is a significant direct cost saving, and increased availability of equipment is also important. For example, in a waste water processing plant, a decision to replace the wetted parts of a galvanised distributor with 316 and the notionally dry parts with 304, reduced maintenance costs by 92% and increased availability from 76% to 98%.

A civil engineering example is the Progresso Pier as shown below where the original pier with carbon steel reinforcement is in ruins after 32 years exporsure. A Nickel Institute funded comparison between the 1940s construction using 304 reinforcement (right pier) and a theoretical pier constructed with carbon steel showed that the carbon steel would have contributed to a 44% greater overall life cost until 2020. It also showed that using stainless steel reinforcement had between 20% and 80% less environmental impact. This low figure was due to the predominance of the mass of concrete compared to the 240 tonne of stainless steel.

GREEN AND SUSTAINABLE

Green projects minimise energy use and one option is to reduce solar loading by installing perforated sunscreens or fixed slats in locations where insolation is high and ambient temperatures are not extreme. Design of perforated sunscreens is a sophisticated but well understood process with standard programs available. There are multiple examples that use stainless steel because it does not require more than rain or simple water washing to retain a bright appearance.  

Finally, increasingly the “green” label means growing plants or other flora along stainless steel wires or supports either in public places as a visual softening or as a deciduous sun screen where stainless steel is required because of the lack of maintenance access to the supports once the vegetation is mature.

In summary, the durability of stainless steel provides substantial reductions in maintenance costs, supports a considerable recycling and reuse process, and provides control mechanisms for energy use.

This article featured in Australian Stainless magazine - Issue 63, Spring 2018

Stainless steel has delivered the confidence it will provide the structural performance and meet the 100-year life-cycle of a new marina development on the New South Wales’ South Coast.

The Waterfront, Shell Cove, is a joint residential and mixed-use development between Shellharbour City Council and Frasers Property Australia located 22km south of Wollongong.

Central to the development is its waterfront location and world-class marina that will offer pontoon berthing for approximately 270 vessels, direct access to the Pacific Ocean, charter boat operations, a public boat ramp and a variety of marina facilities and services.

Stainless steel reinforcement has played a significant role in the structural design and construction of the marina, with over 318 tonnes of grade 2304 lean duplex stainless steel reinforcement bar (rebar) supplied by ASSDA Member Valbruna Australia. Ranging in diameters from 8mm to 25mm, stainless steel rebar was used in all pre-cast elements to form the marina sea walls, marina steps and boat ramps and installed by Coastwide Civil.

The original project specification was for alternative materials and products with cathodic protection and sacrificial anodes that struggled to exceed a 50-year life-cycle guarantee. This specification was superseded by a requirement for a 100-year life span, and the use of stainless steel provided the best solution, as well substantial cost savings around constructability and man hours per tonne required.

Stainless steel rebar offers structural longevity in many environments with exceptional corrosion resistance in harsh marine developments. Its specification in this landmark waterfront development meets the expected minimum 100-year life and was also critical to minimising ongoing maintenance costs. This was an important consideration to avoid future maintenance closures due to corrosion issues and to ensure continued public accessibility to the waterfront promenade for all residents and tourists.

In addition, the use of stainless steel rebar significantly reduced the amount of concrete cover required, also minimising costs and resulting in a more lightweight and higher tensile strength structure.

Valbruna Australia’s commitment to stock large volumes of stainless steel rebar on the floor in Australia meant no delays were experienced during the project’s supply term, including meeting the 20% increase in supply quantity during installation. Coordinated supply was critical to the on-time completion of the project, which was further impacted by narrow site delivery windows and limited set down holding areas.

The scheduling, cutting and bending of the stainless steel rebar to tight precast tolerances was completed by Mesh & Bar, and performed at a dedicated stainless steel facility to prevent contamination risks.

All stainless steel welds were completed in a controlled environment, and pickled and passivated by Waeger Constructions.

Construction of the residential and mixed-use infrastructure will continue into next year, with the marina due to take water by the end of 2019. Once completed, Shell Cove will also boast a vibrant town centre and retail precinct, community centre and library, foreshore dining and waterfront tavern, and boutique accommodation.

This article featured in Australian Stainless magazine - Issue 63, Spring 2018.
 

Innovative Melbournian architecture has delivered a striking stainless steel feature in the city’s latest commercial mixed-use development.

Melbourne is setting the benchmark for world-class design with Collins Square now one of Australia’s largest CBD commercial precincts, covering an entire city block on Collins Street. Already home to a number of leading global corporations and the revitalised heritage-listed Southern Goods Shed, the $2.5 billion project will at completion comprise of five commercial towers and over 10,000sqm of retail space.

Black mirror finish stainless steel columns are the focal point in the lobbies and food precincts of Towers Two and Four of Collins Square. Soaring an impressive 10m to 12m tall at a diameter of 1300mm, the stainless steel-clad columns are complemented by floor-to-ceiling window glass and natural stone masonry walls and floors.

ASSDA Member Fabmetal Specialists supplied, fabricated and installed the grade 304 stainless steel circular columns, using its own patented column cladding system. Twenty stainless steel clad columns were installed across the two towers.

Fabmetal Specialists’ pre-fabricated the customised stainless steel column panels from 1.2mm sheet, and using a modular cladding method, installed the panels with a unique fixing system allowing no visible fixings or caulked joints.

Coloured stainless steel in a No. 8 mirror finish from the company’s TiVox range was used for the project and specified for its upmarket appeal and elegant aesthetics. In addition, stainless steel also offers durability and ease-of-use during construction.

Providing a true mirror reflection, the black chromatic colour (known as ‘Jet Mirror’ in the TiVox range) was achieved with a titanium film using a Physical Vapour Deposition (PVD) coating process. The coating technology offers a number of high chemical and technical features, including resistance to abrasion, scratches and corrosion, and overall minimal maintenance.

The end result is an innovatory, high quality stainless steel finish, bringing life to the surrounding activity of Melbourne’s place-to-be for business and leisure.

This article featured in Australian Stainless magazine - Issue 62 Winter 2018.

With the use of stainless steel, indigenous artist Kylie Graham’s interest in Whadjuk Noongar customs and culture has helped bring a symbolic sculpture to life at Perth’s recently revitalised Scarborough beach. 

The people of Whadjuk Noongar are the traditional owners of Perth. The Ethereal Welcome Hand sculpture represents a hand casting sand which acknowledges the custodians, the people of Whadjuk and their enduring spiritual connection to the land and sea. 

In respect to Noongar cultural customs, visitors are to throw a handful of sand into the water as an introduction of themselves to the spirits and ancestors. It was only fitting for the 3D sculpture to cast its presence near water and is primarily constructed from grade 316 stainless steel supplied by ASSDA Members Midway Metals and Stirlings Australia. 

The 6.5m tall sculpture uses 5mm stainless steel plate throughout the entire wire frame hand spanning 4m long. The finish is 2B and all the welds are TIG welded, cleaned and passivated. The four support columns are also fabricated from 316 stainless steel. 

Illustrated in the palm of the stainless steel hand, pouring down to the ground is gold anodised aluminium cladding, with perforations backlit with LED lights which can be programmed for multiple occasions.

At the back of the hand, the design of a dolphin and three fish is laser cut through the stainless steel, to reflect the importance of the relationship between Noongars and mammals.

Stainless steel was chosen as the main sculptural material for its durability, excellent corrosion resistance and aesthetically-pleasing properties. This stunning work-of-art was designed, fabricated and installed by local art consultant Forever Shining.

The Ethereal Welcome Hand is one of six pieces of artwork along the redeveloped foreshore and can be found between the surf club and swimming pool. It has been welcoming the public since March 2018 and will continue to do so for many years to come thanks to the durable life span of stainless steel.

This article featured in Australian Stainless magazine - Issue 62 Winter 2018.

Ferritics account for approximately 25% of stainless steel use worldwide. The name arises because these alloys have similar properties to carbon steels when they are bent or cut and, unlike the well-known 304 and 316 austenitic grades, ferritics are strongly attracted to a magnet.

There is a major misconception that ferritic stainless steels are less corrosion resistant than austenitic alloys. On the contrary, for any required level of corrosion resistance (or Pitting Resistance Equivalent [PRE]), you can select a specific stainless steel from either the austenitic or ferritic family depending on the physical properties desired. Another similarity of these two families of stainless steel is that neither can be hardened by heat treatment. However, a significant difference is that, in common with carbon steels, ferritic stainless steels become brittle when used in sub-zero temperatures. The actual transition temperature depends on the specific alloy, but it increases for welded fabrications.

Often regarded as the simplest stainless steel alloy, ferritics are steels (iron and a small addition of carbon) with at least 11% chromium added to produce the passive chromium oxide film. This self-repairing chromium oxide layer gives stainless steel its corrosion resistance. The first stainless steels developed in 1913 were ferritics with a high carbon content. Today, those alloys are called martensitics and are used for high hardness blades or wear resistant surfaces. The alloys now known as ferritic stainless steels have been used commercially for many decades, primarily as sheet cladding up to about 3mm that do not require welding. The Fujitsu building in Brisbane for example is clad in profiled ferritic stainless steel sheet, and the use of perforated and solid ferritic stainless steel sheeting is featured in the ceiling and fascia paneling in Sydney’s Wynyard Walk.

Apart from the 12% chromium utility alloys, the sheet thickness limits for the supply and welding of ferritics are due to its metallurgical structure. Unlike austenitic stainless steels, the microstructure does not transform during welding, and so the initially microscopic ferrite grains can grow and embrittle the metal.

Ferritics have gained wider acceptance since changes in its alloy design and production methods allowed welding. The adoption of the Argon Oxygen Decarburisation (AOD) refining process in the 1970s also assisted, allowing both the reduction of impurity levels and, critical for welding, good control of both carbon and nitrogen content.

Table 1: Selected Ferritic Alloys

Notes:
A. Balance of composition important to avoid welding corrosion issues
B. Also derivative grades with low carbon and Ti/Nb to allow welding
C. Not good indicator of corrosion resistance especially if welded because of high carbon
D. For comparison, the PRE of 304 is ~18.5 and 316  ~23.5.

Available Ferritic Alloys and Applications
The Ferritic Solution (TFS), published by the International Stainless Steel Forum, lists 71 ferritic alloys in ASTM, EN and JSA standards, although most are in sheet form. For example, A240 lists 26 alloys as flat product while ASTM A276 only has nine alloys listed as bar or shape. TFS classifies ferritic alloys into five groups based on chromium content:

- Chromium (10.5% to 14%)
- Chromium 14% to 18%)
- Titanium and/or niobium added to avoid sensitisation with welding
- Molybdenum additions for corrosion resistance
- Weldable group of alloys with higher corrosion resistance and chromium >18%, added molybdenum and low impurity content.  

Table 1 lists common names, UNS numbers, typical compositions and applications of representative alloys. There are also families of alloys derived from the same root UNS numbers. In addition, a growing number of proprietary ferritic alloys have been and are being developed especially in Japan. The PRE column is a measure of corrosion resistance based on composition, i.e. PRE = %Cr + 3.3% Mo. The 16%N term used for austenitic and duplex grades is omitted because nitrogen is virtually insoluble in ferritic alloys. 

Corrosion and Heat Resistance
These are not the same. Oxidation (or scaling) resistance of stainless steels in air depends on the stability of the oxide layer (or scale) on the surface. This is not the thin (nanometres) passive film formed in water but the thicker, high temperature oxide formed above about 250oC. Its protective properties depend on its bond to the metal surface below. In turn, this depends on the relative expansion of the oxide and the metal surface. 

As shown in Table 3, ferritic alloys have low thermal expansion compared to austenitics, which means the adhesion of their protective scale is better in thermal cycling conditions. In practical terms, this means that ferritic alloys have higher scaling temperature limits for intermittent service than in continuous service, whereas the reverse is true for austenitic alloys.

At temperatures in the high hundreds (oC), the relatively low strength of most ferritic alloys limits their use, although the niobium-treated ferritics have similar strength to the austentic alloys. Ferritic (and duplex) grades should not be used in the band around 475oC as metallurgical phase transformations cause embrittlement during extended exposures.

In oxygen-rich environments, the simple wet corrosion resistance of ferritic, austenitic and duplex alloys is well-described by the PRE index as given in Table 1. The predictions are for a passive surface and will be unreliable if the surface has been contaminated by carbon steel or if welding heat tint has not been removed.

PRE does not influence the spidery cracking that occurs in austenitic alloys that are stressed and exposed to warm or hot chloride solutions. Ferritic and duplex grades are effectively immune to this stress corrosion cracking attack and it is the reason why instant hot water tanks used in kitchens are ferritic alloys, usually 444.

Left: Fujitsu Building in Brisbane is clad in profiled ferritic stainless steel sheet. Right: Ferritic stainless steel sheeting featured in the ceiling and fascia paneling in Sydney's Wynyard Walk.

Mechanical and Fabrication Properties
Because of their microstructure, ferritic stainless steels behave very similarly to carbon steels in bending, roll forming, spinning and shaping. Fabricators can use the same techniques for ferritics when forming roofs or couplings.

Ferritics do not cold-work like austenitics and so, for the same thickness, they have less springback. Although deep drawing is easier for ferritics than austenitics, the higher chromium ferritics can suffer from ridging, so there are not many deep drawing applications. Stretch forming can only be to about 50% of that achieved with austenitics, as might be expected from the difference in ductility. Table 2 compares the mechanical properties of several ferritics with 304 and carbon steel. In broad outline, ferritic stainless steels have a higher yield (or strictly 0.2% proof stress) than austenitic stainless steels, lower tensile strength and about half the elongation at fracture. The modulus of elasticity is similar to carbon steels, so deflections under loading will be comparable.

Table 2: Typical room temperature mechanical properties

With the exception of the 12% chromium utility grades, welding of ferritics requires more skill than welding austenitics because of their sensitivity to impurities, which may cause cracking in the heat-affected zone. Very thorough attention to cleanliness is required as well as the use of high purity shielding gas and care in gas shielding – particularly outside the workshop where drafts can be a problem. Because of the risk of grain growth (and consequent low toughness) with extended periods at high temperatures, low heat input is required and pulsed welding equipment is a useful tool. This metallurgical sensitivity is the reason why ferritics are rarely available in thicknesses greater than 3mm. However, the low thermal expansion and better thermal conductivity of ferritics compared to austenitics means that welding distortion is less critical for all ferritics (refer to Table 3).

Like all stainless steels, the corrosion resistance of welded ferritics is restored if all heat tint is removed after welding, preferably by pickling. Mechanical abrasion is a good second best provided the surface roughness is not excessive.

The 12% chromium utility ferritics are widely used in welded thick structural sections in coal wagons, heavy vehicle chassis, high temperature exhaust ducting, fire proof fencing, low corrosion wear locations and multiple structures where aesthetics are not the primary consideration, i.e. where a brown adherent cosmetic haze is not considered a problem. The 12% utility ferritics are discussed in more detail in Australian Stainless #52 (available at www.assda.asn.au).

SUMMARY

Some ferritic grades have been in large scale commercial production for many years, but the variety of grades now available has only been possible because of new melting and refining technologies. A large number of grades now exist, and a great deal of active research and alloy development is continuing.

Ferritic stainless steels offer:
- Formability similar to carbon steels and can be readily bent, roll formed, pressed to shape or spun
- Higher yield strength and lower ductility than austenitics
- Comparable range of corrosion resistances to other stainless steel families
- A wide range of possible applications.

Table 3: Physical properties of Ferritic and Austenitic stainless steels

This article featured in Australian Stainless magazine - Issue 62 Winter 2018.

World-class infrastructure demands high quality products and long-term asset performance, both of which have been delivered through superior workmanship and the use of stainless steel.

Fuchs Lubricants Australasia opened its new $33 million purpose-built plant at Beresfield, New South Wales in February 2018. Operating in Australia since 1979, Fuchs’ expanded and relocated from its original factory in Newcastle due to strong business growth, now being the only major lubricants company to still manufacture products in the country.

Fuchs’ new plant is a blending operation, features two highly-developed laboratories and is three times larger than the old factory, producing 10,000 lubricant products for applications in industries ranging from mining and automotive to transport and food.

Stainless steel has been integral to the plant expansion project design and construction, being the material of choice in demanding environments that involve high heat and aggressive substances. Offering structural integrity and excellent corrosion resistance in high temperature applications, stainless steel is vital in the construction of tanks, pressure vessels, valves and pipework. 

The successful collaboration of TFG Group and Furphy Engineering resulted in the project being completed on time and within budget, each using their in-house stainless steel design and technical expertise to deliver a world-class facility supporting Fuchs’ continued expansion and investment in the Australian lubricants market.

This article featured in Australian Stainless magazine - Issue 62 Winter 2018.

Taking pride of place within Perth’s Optus Stadium Park is the Arbour featuring a stainless steel cable net canopy delivered by ASSDA Member Structural Dynamics.

The 60,000-capacity arena is the latest major development to hit Western Australia’s capital, boasting a world-class multi-purpose venue that combines innovative design with community infrastructure.

The impressive Arbour stands 10m tall and 20m wide, and stretches 450m around the south side of the Stadium. It connects a new six-platform railway station to the Swan River, over which the Matagarup Bridge is currently being constructed to provide pedestrian access to East Perth.

Over a thousand stainless steel cables were installed on the 43 arches that make up the Arbour to create a tensile structure in the form of a canopy. Suspended on the structure using bespoke fittings are 3,076 bronzed artwork panels reflecting Whadjuk and Noongar stories. 

Stadium Park was constructed on wetlands with cultural heritage significance to the Indigenous community, and its rich Aboriginal history was the inspiration behind the Arbour’s design.

More than 13 tonnes of grade 316 stainless steel was used, including in excess of 14km of 16mm and 8mm hamma^TM X 1x19 wire rope supplied by ASSDA Member Arcus Wire Group, 20,000 bespoke fittings and over 34,000 screws.

Stainless steel was specified for the cable net canopy for its strength and durability to withstand the harsh Western Australian weather conditions, including powerful coastal winds driven from the Indian Ocean. The 16mm edge cables on the structure were tensioned to forces up to 52kN, with the 8mm longitudinal and transversal cables tensioned up to maximum of 11kN.

In addition, the high quality and aesthetical value of stainless steel complemented the Arbour’s design in creating an eye-catching structure for patrons.

Structural Dynamics provided value engineering and practical advice to the project engineer Maffeis Engineering and project architect Hassell on how to best integrate stainless steel tensile systems into the design.

Their in-house team of engineers used structural and finite element analysis as components of the detailed analysis and modelling on how the cable design would behave and interact within a tensile architecture installation.

Structural Dynamics also worked with engineering firm Partridge to undertake the final design, review, slip testing of the bespoke cable clamps and final sign off for the project. Each of the eight different types of cable edge clamps were sent to the National Association of Testing Authorities’ (NATA) accredited laboratory for slip testing under wet and dry conditions to ensure their strength and adequacy.

The cable fittings were designed to the AS 1170 series: Structural Design Action, AS 4100: Steel Structures and AS 2759: Steel Wire Rope – Use, Operation and Maintenance.

Structural Dynamics’ Project Manager Shaun Salmon explained the logistics of the assembly of the Arbour whilst maintaining safe and continued access to the Stadium for more than 1,000 workers. ‘It was important during the installation process that our team of skilled and qualified tradesmen and riggers followed the approved construction sequencing and quality management system processes whilst not impeding access to the Stadium from the primary entry point on the southern concourse. Both temporary and permanent bracing measures were used throughout construction along with sequential tightening and regular cable tension testing to achieve the design intent drape and sag of the cable net canopy and not applying adverse force to any single point on the structure.’

Structural Dynamics’ collaboration with the multiple stakeholders involved in the Arbour design and construction ensured the successful delivery of a custom-designed stainless steel cable net canopy providing the flexibility, tensile strength and structural performance required.  

Optus Stadium officially opened on 21 January 2018 and is the new home game venue of local Australian Football League teams Fremantle Football Club and the West Coast Eagles.

Arbour photos courtesy of Structural Dynamics. Photography by Abigail Harman.

Aerial photo of Optus Stadium Park courtesy of MakMax.

This article is featured in Australian Stainless Magazine #61.

Stainless steel is playing a vital role in the structural integrity of a new state-of-the-art library at one of Brisbane’s most prestigious boys’ school.

The Centenary Library at Anglican Church Grammar School was designed by Brand + Slater Architects, and the ambitious project was part of the school’s master plan to provide a technology-rich, world-class centre for its 1800 students. Comprising four levels, the tertiary-inspired building features an extensive range of learning spaces including a 250-seat lecture theatre, teaching and meeting rooms and over 80 individual study areas.

The library stands 23.5m tall on a heritage-listed part of the school campus. Paying homage to the school’s history whilst appealing to a contemporary aesthetic, the library exterior features an intricate brick façade backed by a stainless steel support and restraint system custom-designed and manufactured by ASSDA Member and Accredited Fabricator, Ancon.

Grade 304 stainless steel was used and specified for its longevity, durability and performance properties to meet the building’s 50+ year design life.

Ancon’s specialist knowledge, manufacturing agility and project management service proved invaluable to the contractor when building the detailed façade of the decorative arches and corbelled brickwork with all structural steelwork now unseen.

Shelf Angle Brick Support

Ancon masonry support systems enabled the large-scale brick cladding installation on this impressive education facility to be completed to the highest safety standards, while showcasing its architectural brickwork features.

Ancon’s MDC and CFA continuous shelf angle support systems carry the intricate brick façade, consisting of freestanding archways and projected brickwork. The MDC stainless steel angles are fixed to the reinforced concrete frame, span a 40mm cavity, and create a horizontal shelf to provide the necessary support for up to 3 metres of brickwork.

Cast-In Channel

Ancon’s 30/20 cast-in horizontal channels were used to provide the fixing between the concrete frame and shelf angles. The channel enabled the necessary horizontal adjustment for the installer, and its compact size eliminated the issue of potential clashes with the reinforcement steel in floor slabs.

Nail holes aided the fixing of channels to timber framework and an infill prevented the ingress of concrete during casting. Cast-in fixings do not generate expansive forces in concrete. It can therefore be used at close centres and often used closer to the edges than expansion fittings.

Wall Ties and Restraint Fixings

To restrain the distinctive brickwork details to the reinforced concrete structure, stainless steel L-shaped SPB and SDB frame cramps were fixed into the reinforced concrete using 6mm FBN expansion bolts.

FBN single expansion bolts are a cost-effective anchor and fix into a hole similar to the diameter of the bolt. This allows the hole to be drilled through the hole in the item to be fixed.

Technical Expertise

As part of Ancon’s free design service, plans were produced illustrating the location and reference of all fixings required. Ancon’s early engagement with the project’s structural engineers, Bligh Tanner, enabled a workable and cost-effective design to be agreed upon prior to the build of the complex masonry features. Sharing their expertise with the clients at this stage of the project meant installation difficulties, site delays and unnecessary remedial measures were avoided.

Centenary Library photo (above); Copyright: Christopher Frederick Jones.

This article is featured in Australian Stainless Magazine #61.

Either while being welded or glistening in the summer sun, the three major families of stainless steel behave differently to each other, carbon steels, aluminium and copper alloys because, as shown in the bar chart, the coefficient of thermal expansion and conductivity - and their ratio - varies.  

While alloys of copper and aluminium have equal or higher coefficients of expansion than austenitic stainless steels, it is the unique combination of high thermal expansion and low thermal conductivity that necessitates special precautions and procedures in the design and fabrication of the most commonly used 304/304L and 316/316L grades of austenitic stainless steel in structures and vessels. Information on handling other families of stainless steels is given in ASSDA’s Australian Stainless Reference Manual.

Distortion during welding

Failure to address thermal expansion and conductivity can result in severe distortion during welding, as differential expansion causes the heat generated by the welding process to remain localised, causing steep temperature gradients  and high localised stresses or surface distortion. Standard welding procedures should be adopted to minimise heat build-up in the weld zone. These include using minimum amperage consistent with good weld quality and controlling interpass temperatures using guidelines provided in Table 5.10 of AS/NZS 1554.6. Clamping jigs with copper or aluminium backing bars as heat sinks on the welds may also be feasible. Other precautions to minimise distortion during welding include efficient jigging or the use of an ends and middle sequence of closely spaced tack welds rather than a straight run. The wrinkled guttering below illustrates the shrinkage problems of poorly planned welding.

The Design Manual for Structural Stainless Steel² indicates that austenitic stainless steels suffer from the same types of distortion during welding as carbon steel, but the higher coefficient of expansion (17 μm/m°C versus 12 μm/m°C for carbon steel) and the lower thermal conductivity (approximately 30% of carbon steel) increase distortion of austenitic stainless steel weldments. Duplexes are between carbon and austenitic stainless steels in thermal expansion coefficient, but the thermal conductivity is similar to austenitics so heat control is still important. Ferritic stainless steels have similar thermal welding properties to carbon steel but require more skilled welders for metallurgical reasons.

The Design Manual also suggests that a number of additional actions can be considered by both the designer and the fabricator to minimise welding distortion and mismatches such as illustrated in the manifold. These include designing with symmetrical joints, designing to accommodate wider dimensional tolerance, reducing cross-sectional area of welds in thick sections (e.g. replacing Single ‘V’ preparation by Double ‘V’ or Double ‘U’), ensuring that good fit-up and alignment are obtained prior to welding, and using balanced welding and appropriate sequences such as ‘backstepping’ and ‘block’ sequences.

Expansion problems after installation

Another problem arising from the high coefficient of expansion of austenitic stainless steels compared to plywood is differential expansion – although water uptake may also be an issue.  In the illustrated case of stainless steel bonded to plywood by adhesive, a maximum length of 3m is recommended to avoid failure of the adhesive bond during thermal cycling. 

Another problem is when panels (even quite small ones) are in full sun and do not have expansion room for the movement since they were installed at (say) 20°C to the 40°C day plus 30°C overheated metal.

In architectural applications with long runs such as profiled roofing, expansion clips should be used to permit thermal movement without localised buckling and failures. As with other metal roofing and cladding systems with runs 3-9m or longer, there are limits to the maximum width of formed profile for the thickness of stainless sheet used. The formed profile must have sufficient columnar rigidity and strength to transform thermal expansion stresses into sliding movement in the expansion clips. For longer runs, expansion joints should be provided every 7-12m, with clearances of 6mm at vertical faces and 12mm where a gutter end abuts a wall. The publication Stainless Steel in Architecture, Building and Construction - Guidelines for Roofs, Floors and Handrails³ illustrates roofing fixtures for roll-formed profiles and the traditional standing seam and batten roll types. In contrast, ferritic guttering and roofing have similar properties to carbon steels with about 62% of the expansion of an austenitic structure.

In stainless steel piping systems, thermal expansion stresses can cause rupture of the support points, buckling of the pipe, or breakage of equipment connected to the piping if the changes in dimensions are not absorbed by expansion joints or flexibility of the piping installation. The Piping Manual for Stainless Steel Pipes for Buildings⁴ provides a guide to assessing thermal stresses and reactions at supports and anchor points, as well as a guide to determining if the flexibility of piping can absorb its expansion. The latter involves an empirical formula which requires that the piping anchor points are at the pipe’s ends, the piping system has no branches, and there are no changes along the length of the pipe (e.g. diameter, thickness, material quality, temperature, etc.). If the flexibility cannot absorb the thermal expansion displacement, then expansion joints, flexible joints or ball joints should be used (after a computer stress analysis of the joint).

Conclusion

Thermal expansion and conductivity are critical determinants when designing and fabricating austenitic stainless steel products and are still important with duplex stainless steels. Early consideration of these elements will ensure a better and longer-lasting product, both aesthetically and structurally.

REFERENCES

1. ASSDA’s Australian Stainless Reference Manual, see also:
   

   Avery, R.E. & Tuthill, A.H. (1992) Guidelines for the Welded Fabrication of Nickel-Containing Stainless Steels for Corrosion-Resistant Services (NI 11 007)

   IMOA’s Guidelines for the Welded Fabrication of Duplex Stainless Steels, 3^rd Edition (2014)

2. Design Manual for Structural Stainless Steel, 4^th Edition (2017): www.steel-stainless.org/designmanual 

3. Cochrane, D.J. (1994) Stainless Steel in Architecture, Building and Construction - Guidelines for Roofs, Floors and Handrails (NI 11 013)

4. Nickel Institute and Japan Stainless Steel Association (1987) Piping Manual for Stainless Steel Pipes for Buildings (NI 12 008)

This article is featured in Australian Stainless Magazine #61.

The new facility in Merrifield Estate on Melbourne's outer northern fringe will allow Dulux to step into the next generation of paint manufacturing technology and innovation. Dulux's aim was to design and construct a state-of-the-art facility, so using quality products was essential to achieve this. Stainless steel in 300 series grades was an integral part of the project design, including storage vessels and over 10,000m of food grade, quality tube complying with AS1528.

CONCEPT STAGE

In 2015, Dulux announced its decision to construct the new state-of-the-art, highly automated paint factory at an investment of $165m.

The Dulux plant, the first of its kind, is approximately 20,000m², built on 17 hectares of land and is due for completion towards the end of 2017. For a project of this large scale, it was crucial that a strong collaborative relationship was set up between Dulux and its chosen suppliers. In relation to the tubing, supply flexibility, reliability and quality was a key requirement and ASSDA Sponsor Prochem Pipeline Products stepped up to the mark and was the successful tenderer. At the outset the total amount of tube was unclear and would only become apparent as the building process unfolded.

Working together with the client, Prochem executed a strategy to provide more than 10,000 metres of stainless steel tube over a nine-month period to complete the project.

Whilst the original engineering design specified pharmaceutical standard ASME BPE, Prochem worked with the client and design team to have this changed to AS1528 due to its suitability for the application and also due to availability of this stainless steel standard compliant product in the Australian market.

THE DESIGN

The design included a number of large and small storage vessels which were fabricated locally and supplied by ASSDA Members and Accredited Fabricators A&G Engineering and J Furphy & Sons. 

A major part of the design involved the supply and fabrication of the AS1528 tubing and included stainless steel fitting and flanges. The fabrication work was contracted to ASSDA member John Beever Australia who worked closely with Prochem to ensure a continuous supply of materials was made available as required. 

The project consumed over 10,000 metres of AS1528 tubular products in a size range from ½” to 8” in outside diameter with the bulk being 2”, 3” and 4”. The fittings used in the project included BSM fittings, tri-clover ferrules and clamps and also a significant amount of ANSI flanges which were all supplied by Prochem and fabricated by John Beever. The overall project quantities were significant and as such a large degree of co-ordination and co-operation was required with numerous manufacturers to meet the project schedule. 

An innovative technique was designed to match the tri-clover ferrules and clamps to the tube and machinery to enable a correct fit-out at site. 

With good co-operation and education, the project also allowed the flexibility to use both stainless steel grades 304 and 316 if availability became an issue. 

With an innovative and co-operative approach involving many ASSDA members, this project was completed on time and within budget, and will support the Dulux paints business for decades to come.

This article is featured in Australian Stainless Magazine Issue 60 (Summer 2017/18).

You return home after a long journey. Imagine being greeted by a beautiful stainless steel sculpture surrounded by landscaped gardens on your return. One ASSDA Member has used stainless steel to symbolise everything we love about our communities: Security, comfort and home.

It’s easy to think of stainless steel in relation to tubes, panels and rolls in the construction industry, but Brisbane-based ASSDA member, Concept Stainless Design, has taken the product and crafted it into stunningly beautiful sculptures for developers Villa World at their new subdivision on the northern Gold Coast.

Located 70km south of Brisbane, Arundel Springs will provide 386 dwellings in a family-friendly environment adjacent to the Coombabah Lakelands Conservation Area and close to Griffith University and light rail services.

Villa World provided the concept design to reflect the organic growth of nature and symbolise the new families and children who will grow in the new suburb. 

The team at Concept Stainless Design adapted the design to match the size of available grade 316 stainless steel sheets. A small curve of 5mm radius was provided at the tip of the fronds to avoid sharp edges. Another small curve of 9mm was used at the gully between fronds to achieve a flawless polished finish.

The sculptures have been designed to withstand winds of up to 160km per hour, an important feature given Arundel Spring’s proximity to the ocean. An internal frame was built to secure the fronds in position, as well as a horizontal base beam hidden within the sculpture and two legs extending down from the base beam into a large buried concrete block. The structural design certification was completed by Concept Stainless Design’s in-house engineer.

The face of each sculpture was manufactured from grade 316 stainless steel sheet supplied by ASSDA Sponsor Dalsteel Metals.

The sculpture faces are joined along the centre line with an invisible polished butt weld, executed by Concept Stainless Design’s highly skilled tradesman at their Brisbane workshop. The faces were bonded to marine ply and “U” stiffeners were formed from grade 316 stainless steel strips then glued and screwed in. The second face was then placed over the stiffeners, glued and screwed to the ply-bonded face.

The entire project took eight weeks to construct and transported to their new home at Arundel Springs. The sculptures were secured in place by concrete blocks and steel bolts provided by Villa World’s civil contractor in under two hours.

Stainless steel was chosen for the sculptures because of its beautiful, smooth and highly polished finish, and for its low-maintenance properties. Surrounded by clear skies, new vegetation and lush grass, the sculptures welcome residents and visitors alike.

This article is featured in Australian Stainless Magazine Issue 60 (Summer 2017/18).