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Stainless steel makes an entrance

A collaboration between ASSDA Members using 'gold' stainless steel has delivered the epitome of opulent luxury at The Star Sydney.

The Star Sydney's multi-million-dollar transformation has seen its Pyrmont Street entrance revolutionise the guest arrival experience, with a porte-cochère facing the glittering Darling Harbour and a refurbished Grand Foyer combining innovative architecture, contemporary art and technology.

Over 4000m2 of grade 316 stainless steel with a gold finish is featured throughout the Grand Foyer and porte-cochère, enriching the luxurious look and feel of the integrated resort. ASSDA Member Steel Color Australia supplied 1mm and 1.2mm thick stainless steel sheet in various lengths from 2400mm to 3500mm and widths of 1219mm to 1500mm 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.

The stainless steel's gold colour was achieved with a titanium film using a Physical Vapour Deposition (PVD) coating process. The environmentally-friendly method vapourises titanium in a vacuum chamber to form an extremely thin layer that bonds to the steel's surface. The process also improves the performance of the steel, increasing durability and resistance to heat, light, abrasion, scratches and corrosion.

In addition, the steel's surface features an anti-fingerprint (AFP) coating preventing oil and finger marks, contributing to a sleek aesthetic finish with minimal maintenance. The AFP coating provides the titanium coating with a timer colour finish, strengthening colour stability and extending the service life of the application.

Suitable for internal and external applications, coloured stainless steel can be used in many design forms and was specified for the bespoke luxurious features in The Star Sydney's Foyer and porte-cochère.

The Steel Color Australia supplied stainless steel sheeting was installed in the Grand Foyer and internal porte-cochère by ASSDA Member Karisma Joinery, across the door portals, elevator door jambs and ceiling panels, columns and wall panels. A V-Groove machine was used to form precise, sharp angles and folds, creating architectural profiles to achieve a seamless upmarket finish and meet the high-end specification.

The stainless steel clad elements for the external porte-cochère, including luxury retailer finishes for Gucci, was fabricated and installed by ASSDA Member Fabmetal Specialists. All profiles and clad elements were fabricated in their workshop in Melbourne, using an in-house V-Groove machine to achieve a crisp bend profile, prior to installation on-site by the Fabmetal team. A split batten system was used to clad the stainless steel elements across the retail facade fixtures, window mullions, headers and kickers. The Fabmetal team were also tasked to clad the revolving doors and overcame challenges with complex curved works, laminating gold stainless steel on to curved fabricated T-sections in power-coated aluminium to create a striking two-tone effect.

In a nod to architectural innovation, The Star Sydney will continue to welcome and awe its guests with its everlasting stainless steel gleam and elegance.

  

 

PHOTO CREDIT: MURRAY FREDERICKS PHOTOGRAPHY. 

This article is featured in Australian Stainless Magazine issue 68, 2020.

 

Stainless steel behind high-tech visual art

Australian designed and manufactured stainless steel wedge wire grating has been instrumental in delivering 'Aquatique', the first sculptural water installation of its design in the Southern Hemisphere.

The Star Sydney's Grand Foyer has been transformed as part of an $850 million redevelopment for the integrated resort. A unique immersive visual experience is now welcoming guests in a masterfully choreographed interplay of light, water, digital art and live performance.

The key elements of the installation include an 8K resolution, 25m wide crescent-shaped digital screen, laser light shows and 'Aquatique', a cascading sculptural water feature spanning 8m with a 2m diameter centre stage.

Central to the design and function of the sculptural water feature is the use of Australian designed and manufactured stainless steel wedge wire by ASSDA Member and Accredited Fabricator Paige Stainless.

PAIGE STAINLESS HEELGUARD® is at the cutting edge of water drainage technology, offering continuous drainage through its 5mm aperture and high-water volume intake and removal efficiency. The water feature was designed with a throughput capacity of 30,000L, with water being pumped up to 15m vertically to the water feature jets, recirculated through the PAIGE STAINLESS HEELGUARD® and reused whilst the water feature is in operation. The key was to minimise water splash during the process with PAIGE STAINLESS HEELGUARD® delivering the brief with its unique wedge design. In addition, stainless steel is an excellent material choice for water drainage technology, offering durability, aesthetics and ease-of-cleaning during maintenance inspections.

Paige Stainless' project scope also included the design, fabrication and installation of the water collection tank, substructure for the grating and centre stage area within the water feature. Over 3.5 tonnes of grade 316 stainless steel was supplied for the project by ASSDA Members Austral Wright Metals and Midway Metals, including 4mm thick plate and rectangular hollow sections.

The water feature body was manufactured at Paige Stainless' manufacturing facility in Caboolture, Queensland, and fabricated in 14 components for ease of interstate transportation logistics, efficient installation and maintenance.

Delivery and installation logistics were a focal point of the design as The Star Sydney was full operational and open to the public during installation. Provisions were made for specific delivery times and material management to make for a successful, non-disruptive transition from truck to site. Careful planning and design resulted in minimal on-site welding and passivation treatment using citric acid by the Paige Stainless installation team.

The water feature uses 100% recycled water. Its sculptural display is complemented by a theatrical light show and digital art canvas inspired by Australian artists, cinematographers and animators. As the world's largest permanent multi-sensory art experience, the Grand Foyer at The Star Sydney is a visual feast entertaining an average 30,000 guests per day.

PHOTO CREDIT: MURRAY FREDERICKS PHOTOGRAPHY. 

This article is featured in Australian Stainless Magazine issue 68, 2020.

SABRE Veto Vessel: Stainless steel plays vital role in Australian research

A scientific quest to search for dark matter has led to the opportunity for ASSDA Member and Accredited Fabricator Tasweld Engineering to fabricate a specialised stainless steel tank, known as SABRE (Sodium Iodide with Active Background Rejection) Veto Vessel to help facilitate Australian research into answering one of the universe's unsolved mysteries.

The University of Melbourne received $5 million in federal funding to build the Stawell Underground Physics Laboratory (SUPL) in an unused gold mine in Western 

Victoria. The facility will house the SABRE Veto Vessel, shielding it from astrophysical particles and enabling a range of experiments to be undertaken to determine the existence of dark matter, a form of matter that does not directly interact with light. Dark matter is by its nature, extremely hard to detect. The SUPL location is approximately 1km underground to use the earth's shield to screen out astrophysical particles, background noise and environmental factors that interfere with signals from dark matter.

The SABRE Veto Vessel was designed by the University of Melbourne in conjunction with FE Consulting Design Engineers and Tasweld Engineering. To deliver the best probability for experimental success, grade 304 stainless steel was used for the vessel's manufacture. In addition to the material's durability, gleanability and corrosion resistance, stainless steel was specified most importantly for a specific property; low radioactive content. The presence of certain radionuclides negatively affects the detection experiments, and therefore sourcing material with low radio emissivity was critical. The stainless steel plate was imported from a supplier in Germany with experience in this application and involved stringent validation testing.

The vessel took 600 man-hours and was manufactured at Tasweld Engineering's Warrnambool workshop to AS 1210 standards with rigorous equipment and welding processes applied to prevent material contamination. All welding was carried out using a TIG process, with lanthanated tungsten electrodes, and all consumables were new to avoid cross contamination. The 2.6m tall, 1800kg vessel features access ports for electrical and other connections.

The SABRE Veto Vessel was completed in October 2019 and has been temporarily installed in a laboratory at Swinburne University of Technology's Wantirna Campus for preliminary testing while the SUPL is being constructed. For the next stage of the project, Tasweld Engineering have been contracted to manufacture an additional flange assembly to allow the use of different attachments during various experiments.

Tasweld Engineering's expertise and superior workmanship, and the use of stainless steel, has delivered a positive contribution to science in a quest to unlock the mystery of dark matter and to a research facility that aims to conduct better quality experiments, including the effects of radiation in cancer cells.

 

This article is featured in Australian Stainless Magazine issue 68, 2020.

AS 1528:2019 - A new edition pitched at food safety, consistency, useability and current practice

The aim of AS 1528: Stainless steel tubes and tube fittings for food processing and hygienic applications is to standardise hygienic tube and fittings for use in dairy, food and beverage manufacturing. It has been successful in maintaining the required food safety standards in Australia and New Zealand.

AS 1528 was first issued in 2001 and developed by an ASSDA group of stakeholders in the manufacture, supply, fabrication and use of stainless steel tube and associated fittings in the food manufacturing industries.

Changing industry practice, some existing errors, internal consistencies and expansion of sizes required a revision of the standard. The drafting journey to bring AS 1528 up-to-date began in 2015 and has been a challenge, but its successful outcome is significant for the industry and a testament to everyone involved.

The new edition of AS 1528 was published in four parts by Standards Australia in October 2019:

Part 1: Tubes

Part 2: Screwed tube couplings

Part 3: Butt weld tube fittings

Part 4: Clamp tube fittings

The revision of the AS 1528 suite of standards from the 2001 edition has brought the documents' technical coverage up to current practice and recognised the target industries in which hygienic tube is used. The suite is easier to understand and use, and facilitates verification of product compliance so that it achieves the required hygienic conditions.

 

What the revision achieved

The 2019 edition achieved all of the original aims, except one (see below). The suite of four standards now presents as a consistent coverage of all the tube and fittings regularly supplied in Australia.

  1. Addition of a consistent set of pressure ratings across all parts of AS 1528. Useful for designers.
  2. The wall thickness tolerance for tube has been changed. Previously it was +nil/-0.10mm for all sizes of tube. Widening it out to ±10% brings it into line with most other tube specifications and makes it more economical to manufacture without compromising product quality. It also then matches the tolerances of the fittings in other parts.
  3. The title now includes 'hygienic applications' in addition to food processing. This recognises the wider range of applications in which these products are already used.
  4. The reference to duplex stainless steels has been removed. In practice all tube and fittings referenced by these standards are austenitic.
  5. All tube and fittings can be produced without grit polishing the internal surface. Internal surface finish is specified by measurable roughness for hygiene cleanability.
  6. Inner tube surface roughness has been set as 0.8µm Ra maximum; this is consistent across all four parts of the standard and is also consistent with US and European specifications. From a gleanability perspective this is adequate. In addition there is now a specified maximum roughness for the inner weld bead, specified as 'Rt'. This is an unusual specification but it does address directly the requirement for cleanability of the remnant weld line.
  7. For the first time there is a stated limit for inner weld surface heat tint (no more than Level 3 in AWS D18.1M, commonly referred to as 'pale straw'). Again this aligns with US and European standards and much research work promoted by ASSDA and others.
  8. Consistent working pressures and temperature ranges have been given for all tube and fittings, with the exception of clamp fittings above 152.4mm.
  9. The range of sizes has been expanded generally up to 304.8mm or 12" diameter, but lesser maximum sizes for certain fittings, depending on market availability. Smaller diameter tubes have also been included as these have some niche applications. Additional wall thickness have been added. It is not anticipated that there will be a sudden move ways from the usual 1.60mm WT and the common OD range, but there were some industry requests for the expanded size range.
  10. Part 2 covering screwed couplings has been completely restructured. The two fundamental types - RJT and IDF/Trapezoidal - are clearly separated, with all dimensional specifications included in Sections 2 and 3. Section 1 deals with the requirements common to both types.
  11. Fittings not previously recognised have now been included. This includes both RJT blank hexagonal nut and an IDF blank cap in screwed couplings (AS 1528 Part 2). Butt weld fittings (Part 3) has addition of crosses, equal radius tees and 45 degree tees. In clamp fittings (Part 4) an end cap has now been included.
  12. The branch lengths of reducing tees and crosses (Part 3) have been clarified. The previous edition have a specification for this dimension that was in some cases contradictory and in all cases confusing. The new requirement is that the branch length, measured as the extension beyond the run surface, is the same as the branch OD.
  13. Reducers, both concentric and eccentric (Part 3), now include the option of a short extension to enable orbital welding.
  14. Reducers are now standardised as 'short reducers', with the 'full flow' reducers still specified but in the absence of request the standard type is short.
  15. New appendices in Part 4 cover a very useful description of clamp conditions for correct installation (App C), specification of grooves for expanded-type clamp liners (App D) and the method for expanding (App E).
  16. Correction of a long list of typos and inconsistencies in dimensions.

 

What was not achieved

The New Zealand market is already using AS 1528 and keen to have it branded as their own, but early discussions between the committee, Standards Australia and Standards New Zealand revealed the cost imposed by Standards Australia to make the project a joint cross-Tasman effort was prohibitive. As a result, the project became simply Australia, but the committee was able to co-opt a New Zealand member, and a tube manufacturer active in both Australian and New Zealand was also included as a Drafting Leader. The project therefore included New Zealand input, even though the document is branded Australian. The committee was mindful that there is substantial cross-Tasman movement of tube and fittings, of manufactured processing equipment, of engineering expertise and of food product, so joint output was essential to maximise all-round benefits.

 

Why this revision was important

The AS 1528 suite is the only fully integrated set of standards to the Australian industry's traditional dimensions for stainless steel tube and tube fittings for hygienic applications.

The Australian food manufacturing industry is critical both because of our high standards for domestic consumption and also as a very significant export earner. Australia has a clean and green reputation that only thrives if we can guarantee freedom from contamination. 

All the commonly used and some niche tube and fitting products are covered and all are consistent.

Food manufacturing plant is getting bigger, so this edition includes provision of larger size tube and fittings. The applications are also increasingly diverse, so an expanded range of products is appropriate.

This revision presents manufacturers of tube and fittings with a clear, consistent and measurable standard for these critical products. The standard offers a pathway to economical outcomes for tube and fittings manufacturers, designers, installers and asset owners.

 

This article was written by Technical Consultant and AS 1528 Committee Chairman, Peter Moore.

This article is featured in Australian Stainless Magazine issue 68, 2020.

Water Delivery Efficiency with Stainless Steel

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.

Luxe Stainless

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.

 

Atlas Steels' Post Incident Safety Revamp

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.

Stainless Steel and Fire Resistance

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 1400oC. 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 300oC 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 870oC (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 475oC embrittlement, however data produced by the International Molybdenum Association (IMOA) shows that this requires more than two hours in the 400oC to 500oC 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 98oC 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 1100oC metal temperature on the flame side, the “safe” side reached 30oC after 40 minutes and 110oC 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 1000oC  to 1050oC 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 620oC whereas steel (with no rust) and 0.4 emissivity would reach 750oC.   

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 ~200oC. By 600oC 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 for  High Performance Enclosures

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.

Stainless Steel: Sustainability and Life Cycle Costing

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 for 100 Year+ Design Life

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.
 

Grand Reflections

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.

 

Stainless Delivers Success

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 Myriad Connections

ASSDA Member and Accredited Fabricator TFG managed the 12-month stainless steel installation project. This included 9km of 304L grade AS1528 tube ranging from 25mm to 101mm in diameter, 1km of pipe, 33 tanks, and the specialised fabrication of a blending platform and pipe racks for a purpose-designed traffic flow system to move and process raw through to final product oils and lubricants around the 25,000m2 plant. The stainless steel materials were supplied by ASSDA Members Prochem Pipeline Products and Stirlings Australia.

After receiving the process design and piping and instrumentation diagrams from Fuchs, TFG’s Foodline Projects division mechanically designed and installed the pipe routes and pipe racks, increasing production capacity from 30 million to 90 million litres per year. Foodline Projects was integral in the success of the project through designing and incorporating 3D models of the pipe routes and racks which improved performance and efficiencies. Foodline Projects also completed the piping and installation of a custom loading arm.

TFG’s Austline Fabrications division designed and completed 3D drawings of the 35-tonne blending platform and pipe racks, and included 40 per cent extra capacity for future expansion. The 40-metre-long and three-tier platform was pre-fabricated in their Perth workshop, then flat packed, transported, assembled and installed on site.

 

Processing and Vessels

ASSDA Member and Accredited Fabricator Furphy Engineering designed, fabricated and supplied 33 grade 304 stainless steel tanks ranging in size capacities of 16kL to 180kL, with material including processed plate supplied by ASSDA Member Vulcan Stainless.

The tank designs were produced by Furphy’s in-house engineering team, accommodating for both heat exchange and agitation requirements to ensure that Fuchs were confident in the ability of the tanks and vessels to perform the required manufacturing operations going forward, all of which were completed to AS1210.

The manufacture of the designs heavily utilised a range of innovative technologies in Furphy’s state-of-the-art workshop, including plasma welders, automated strake manufacturing and seam polishing systems, full undercover hydrotesting and QA/QC sign off, as well their own in-house laser welded cavity plate. While widely embraced in Europe, Furphy Engineering is currently the only manufacturer with laser welded cavity plate technology in Australia, a key part of the heat exchange design on this project.

The heat exchange loading on the pressure vessels was high given the materials and size of the equipment, and the laser welded cavity plate system enabled additional heat exchange surfaces to be included on the cones, increasing the active thermal exchange area and optimising the efficiency of the system to ensure effective operation.


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.

Stainless Provides Strength and Style

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 hammaTM 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 Sustains Intricate Brick Facade

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.

Thermal Expansion and Design of Stainless Steel Fabrications

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, 3rd Edition (2014)

  2. Design Manual for Structural Stainless Steel, 4th 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.

 

Collaboration Brings Results

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).

Art Symbolises Community

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).

The Family of Duplex Stainless Steels

The use of duplex stainless steels has grown globally based on their strength, corrosion resistance and a range of properties that improve equipment life.

The name duplex is sometimes used to describe Alloy 2205 (UNS S31803 or UNS S32205), however duplex is a family of alloys ranging from lean duplex and standard duplex to super duplex stainless steel.

HISTORY

Duplex stainless steel was first developed in France and Sweden in the 1930’s, with the early grades becoming a forerunner for AISI 329, but a lack of control over the chemistry and lack of adequate welding products and techniques impeded development of the product.

Cast versions eventually became available and were subsequently used successfully in many industries where some corrosion, wear and strength were required.  

Areas such as pump components saw a raft of duplex grades developed in standard and super duplex. It should be noted that further work or welding was not required with these particular forms.

In the 1970’s Swedish manufacturers produced and marketed what could be described as a lean duplex called 3RE60 (UNS S31500) with lower chromium, nickel and nitrogen than grade 2205.

3RE60 had success with tubing and displayed excellent resistance in replacing 304 and 316 tubes that had previously failed due to chloride-induced stress corrosion cracking.  The use of 3RE60 in vessels was less successful due to issues such as inter-granular corrosion (IGC) from early welding techniques. The issue was not with the grade but with fabrication, as well as the melting technique to enable control of alloying elements to provide a consistent structure and provide predictable strength and corrosion control.

In the late 1970’s grade 2205 arrived in the market, initially as a tube, then in flat-rolled and other products. The point-of-difference from earlier attempts was well-documented welding technique control, which lead to the increased usage of duplex.

The grades displayed higher strength than standard austenitic grades, excellent resistance to stress corrosion cracking and improved pitting resistance. The other driver was the rising price of nickel, which added a commercial advantage over using a lower nickel duplex product.

GRADES OF DUPLEX

The grades are listed in three groups; standard, lean and super.

The major difference between each grade is corrosion resistance.  This is based on a Pitting Equivalent Number: 

(PREN) = %Cr + 3.3 x %Mo + 16 x %N.

This is a comparative rating that relates to the critical pitting and crevice corrosion temperatures in hi chloride environments (CPT and CCT respectively).

DUPLEX TYPE PREN
Standard Approximately 35
Lean 25-30
Duplex Above 40

USES OF DUPLEX STAINLESS STEELS

Stress corrosion cracking (SCC) is a form of corrosion that occurs with a particular combination of factors:

  • Tensile stress;
  • Corrosive environment; 
  • Sufficiently high temperatures: Normally above 60°C but can occur at lower temperatures (around 30°C in specific environments, notably unwashed atmospheric exposures above indoor chlorinated swimming pools). 

Unfortunately, the standard austenitic steels like 304 (1.4301) and 316 (1.4401) are the most susceptible to SCC. The following materials are much less prone to SCC:

  • Ferritic stainless steels;
  • Duplex stainless steels;
  • High nickel austenitic stainless steels;

 The resistence to SCC makes duplex stainless steels suitable for many processes operating at higher temperatures. Examples of the successful use of duplex stainless steel are hot water tanks, brewing tanks and thermal desalination vessels.

WHERE CARE IS REQUIRED WITH DUPLEX STAINLESS STEELS

Duplex stainless steels can also form a number of unwanted phases if steel is not given the correct processing, notably in heat treatment. Phases like sigma phase leads to embrittlement, meaning the loss of impact toughness, but sigma phase also reduces corrosion resistance.

The formation of sigma phase is most likely to occur when the cooling rate during manufacture or welding is not fast enough. The more highly alloyed the steel, the higher the probability of sigma phase formation. Therefore, super duplex stainless steels are most prone to this problem. Another form of embrittlement occurs above 475°C, and it can still form at temperatures as low as 300°C. This leads to the design limitations on the maximum service temperature for duplex stainless steels.

SUMMARY: DUPLEX CHARACTERISTICS

Compared to the austenitic and ferritic stainless steels, duplex can give:

  • Up to double the design strength;
  • Good corrosion resistance depending on the level required;
  • Good toughness down to -50°C;
  • Excellent resistance to stress corrosion cracking;
  • Welding in thin and thick sections with care;
  • Additional effort required due to high mechanical strength;
  • Up to 300°C maximum in service.

  

Author: Trent Mackenzie is a metallurgist with more than 35 years experience in the industry and General Manager of ASSDA.

Photos courtesy of Outokumpu.

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

Wynyard Walk: Where Beauty Meets Function

New infrastructure in the heart of Sydney is set to transform the busy transport hub and provide a stylish new gateway to the Barangaroo development.

21 June 2017

A growing population in Australia's most populous city calls for innovative design, so when the NSW State Government commissioned construction of the Wynyard Walk, ASSDA Sponsor and Accredited Fabricator Stoddart stepped up to the challenge.

The Wynyard Walk forms one of several solutions to break congestion in the Sydney CBD, allowing pedestrians to move from the Wynyard transport hub to the new development at Barangaroo waterfront in six minutes, avoiding steep hills, busy intersections and inclement weather events.

With an estimated 75,000 commuters using the busy hub every day, traffic flow is expected to increase to 110,000 over the next seven years in what is traditionally Sydney's third busiest station.

The tunnel will become the main arterial connection between Barangaroo and the city's transport network and provides vital infrastructure into the future.

THE PROJECT

Alongside CPB Contractors, Stoddart incorporated over 1,600m2 of perforated and solid stainless steel sheeting fabricated into ceiling and fascia pannelling installed in the Clarence Street entrance facade and the tunnel lining. The new Clarance Street entry point is a multi-level portal descending to Wynyard Station via escalators and elevators.

ASSDA Sponsor Austral Wright Metals supplied the project with over 50 tonnes of 445M2 grade stainless steel sheet.

A major consideration for the design team was to ensure aesthetic value for commuters and visitors alike.

THE DESIGN

Inspired by nature and Sydney region geology, the design concept for Wynyard Station focused on flow, with all materials selected to create a sense of motion as part of a unified architectural expression.

The intricate patterns were all designed and executed within Stoddart's factory in Karawatha, Brisbane. The design work was completed wholly on CAD and Solidworks to ensure each panel fitted exactly into the patter and alongside adjacent panels. The Brisbane facility completed all aspects on the manufacture.

The external facade from Clarence Street to Wynyard Station was completed using perforated metal panels on the new access area via escalators and elevators down to the station several levels below.

The internal fitout, including the ceilings, walls and bulkheads, were all constructed from perforated stainless steel as well as solid stainless steel panels.

The complicated ceiling pattern proved challenging, but not insurmountable, resulting in a beautiful floating effect beckoning commuters along.

The project signalled the completion of Stage One of a $160 million upgrade to Wynyard Station.

 THE OUTCOME

The Kent Street level incorporates an extraordinary twenty-metre digital media screen which showcases flowing images of time, travel and places from all over Sydney throughout history, providing commuters with a far more entertaining commute than traditional toilet-block-tiled underground tunnels.

For tens of thousands of commuters who daily traverse the tunnel, Wynyard Walk is a time and energy saving alternative to the street level traffic roulette they once faced.

The added bonus is the stunning, aesthetically pleasing surrounds, the shiny panels and beautiful architecture, all of which was made possible by the use of stainless steel.

This article is featured in Australian Stainless Magazine Issue 59 (Winter 2017).