ASSDA Member and Accredited Fabricator Arcus Wire Group has delivered an innovative duplex stainless steel wire rope cable solution for a hydropower project in the Middle East.

The 344MW Kokhav Hayarden pumped storage hydropower plant is located 120km northeast of Tel Aviv. The project is the first and largest of its kind in Israel, as well as the lowest of its kind globally. The powerhouse lies 275m below sea level and features two 3.1 million m³ reservoirs at different heights. Expected to be operational in early 2023, the hydropower station is designed to provide flexible backup power and stability to the national electricity grid of Israel.

Arcus Wire Group was engaged by GE Renewable Energy to manufacture and supply the cables to form part of a guiding system for the draft tube gates and stop logs for the lower surge shaft of the power station.

The original project brief specified eight identical wire ropes approximately 110m in length with a diameter of 35mm constructed of a half-locked coil with an internal core of large diameter wire, capable of a permanently applied load of 100kN in an underwater application. A long working life was a critical requirement as maintenance of the cables was not an option once in place. 

The initial consideration of materials in order of preference was carbon steel (heavy zinc coating), austenitic stainless steel and duplex stainless steel. The water baseline data for the application during operating conditions were: 

• pH value: Min 6.50 pH, max 9.00 pH 

• Temperature: Min 2°C, max 33°C

• Total Dissolved Solids (TDS): Max 2,200mg/L

• Hardness: CaCO³ Max 960mg/L 

• Alkalinity: CaCO³ Max 436mg/L 

• Iron concentration: Max 320µg/L

• Chloride (CI^-) ) concentration: Max 1,000mg/L 

• Sodium (Na⁺) ) concentration: Max 504mg/L 

• Magnesium (Mg²⁺) ) concentration: Max 144mg/L

• Silica and other hard particles with hardness >5 Mhos: 

  • Particle diameter >_ 50µm: Maximum concentration = 20mg/L

  • Particle diameter >_ 1.5µm: Maximum concentration = 50mg/l

The cable guiding system required one part of the wire rope to be attached to an anchor embedded in concrete and permanently submerged in water exposed to highly corrosive conditions. The top part of the cable is connected to a post-tensioned wire located above ground and exposed to air, with temperatures at a maximum of 45°C and humidity of up to 75%. Post-installation, the wire rope cables will not be accessible for maintenance for up to 30 years.

ASSDA was consulted during the design phase, and as the specification evolved, the client identified stainless steel as a more suitable and sustainable option than carbon steel wire ropes for the submerged application. Considering the maximum temperature and minimum pH level, grade 316 stainless steel would be at its limits, particularly with the crevices that are characteristic of wire rope. 2205 duplex stainless steel was recommended and ultimately chosen as the material of construction to reduce the risk of pitting and crevice corrosion, in addition to its tensile strength, longevity, and life-cycle cost-effectiveness. 

The final design specification delivered alloy grades 1.4362, 1.4462 and 1.4501 duplex stainless steel wire rope cables, half-locked coil with an internal core of large diameter wires and a 30-year lifetime warranty.

The terminations proposed and subsequently selected for use were grade 2205 duplex stainless steel swage forks. They were designed specifically by the Arcus Wire Group team for the 26mm wire rope and a pin diameter of 40mm to allow connection to the anchor at the bottom and the post-tensioning system at the top.

Arcus Wire Group worked with its mill and manufacturing partners to produce and fabricate 970m of 26mm diameter 6x19 SL and IWRC construction 2205 duplex stainless steel wire rope and 20 units of 2205 duplex stainless steel fittings. Seale construction (SL) is a wire rope construction that offers excellent breaking load characteristics. It is used in a wide variety of applications and is resistant to wear and abrasion due to its larger outer wires. An independent wire rope core (IWRC) adds strength to the total length of the rope and reduces the amount of stretch during service.

Material testing was performed on the wire rope cables.
This included destruction testing of a 3m sample cable to measure the breaking strain (breaking at 456.061kN as tested on a horizontal tensile testing machine calibrated to AS 2193: Calibration and classification of force-measuring systems),
10 rounds of cyclic loading to 100kN and unloading to 1kN of an 11m sample cable and loading up to 1.8 times the maximum working load of 180kN to determine elongation under the various conditions. All cables delivered conformed to EN 12 385-4: Steel wire rope.; EN 13411-8 Terminations for steel wire ropes – Safety – Part 8: Swage terminals and swaging; and EN 10088-3: Stainless steels – Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes.

The duplex stainless steel wire cables were assembled, swaged, tested, and quality certified at Arcus Wire Group’s facility on the Gold Coast, Australia, and shipped over 14,000km to the project site in Israel. The final delivery included 8 x hamma® 26mm diameter 2205 duplex stainless steel wire cables measuring 111.4m and weighing over 325kg each. 

Arcus Wire Group has delivered Australian stainless steel innovation and service delivery at its best with the supply of its wire rope cable solution meeting the exacting demands, life-cycle and performance expectations of Israel’s new hydropower station.

This article is featured in Australian Stainless Magazine Issue 76 (2022).

When working with stainless steel assets, a lot of attention is put into getting the ‘pre-install’ aspects right. Design, specification, fabrication, and commissioning are all equally important, but how the stainless steel in these assets is cared for and maintained is just as critical for optimum life and performance. 

ASSDA Member Kleanwell specialises in asset management through the provision of cleaning and maintenance programs. Their work focuses on products where stainless steel is predominant - lift and elevator cladding, facades, awnings, and ducts among many others. 

Jessica Wehbe, Director of Strategic Relationships at Kleanwell, says there is a clear gap in awareness and communication between the pre- and post-installation stages, where contractors “do not know how to maintain their assets and the client at the end of the day is left scratching their head”. Jessica strongly believes there is a need for “clear communication between all parties that are involved from the design, manufacturing and installation, and maintenance teams” at the very early stages. This presents opportunities to set strong specifications (properly aligned to desired maintenance budgets and plans), and expectations around future material performance. 

The well-worn phrase “stainless steel is low maintenance, not NO maintenance” should be embedded as early as possible.  

A recent project Kleanwell completed at Sydney Olympic Park involved major restoration works to 21 lift landing doors with 15 years of poor maintenance. The before and after images show a dramatic improvement, however, pit-like artefacts remain. A basic cleaning regime implemented post-commissioning would likely have resulted in better aesthetics and lower cost than the recent history shows.

According to ASSDA Technical Specialist Dr Graham Sussex, some useful things to remember are:

• If an adjacent window needs cleaning, clean the stainless steel as well.
• Regular planned washing preserves the stainless lustre.
• Never use abrasives or bleach when cleaning stainless.

This article is featured in Australian Stainless Magazine Issue 76 (2022).

Stainless steel mesh has combined form and function in a patient-centred design to deliver a safe, outdoor sanctuary for recovering mental health patients.

Ancient civilisations understood the critical importance of daylight associated with human health, happiness, and wellbeing. Today, there is increased interest in green architecture, with natural light and air becoming a significant design consideration. Studies suggest that light and nature should be strongly considered when building new medical facilities, because of their positive effects on recovery.

Austin Hospital in Melbourne’s north-eastern suburb of Heidelberg is a leading healthcare, teaching and research facility renowned for its specialist services in mental health and rehabilitation. A $15.2 million expansion of the hospital’s Short Stay Observation Unit and Psychiatric Assessment and Planning Unit in 2016 aimed to deliver dedicated mental health care to address the demand and growth of emergency department presentations.

The Short Stay Observation Unit was built above the ambulance bay and includes a lounge that opens up to an outdoor space filtered with natural light, fresh air and unobstructed views. Crimsafe’s Tensile-Tuff® stainless steel security mesh screens were specified for the enclosed outdoor area balustrading as the ultimate solution for providing exceptional strength, transparency and multi-faceted safety and security properties. Tensile-Tuff® Crimsafe mesh does not compromise on visibility or airflow and is well-equipped to deliver on aesthetic appeal with the structure also being the main feature of the hospital’s external façade.

Manufactured and delivered by Crimsafe, the commercial strength screens are made from 0.9mm, grade 304 stainless steel wire and were fabricated in a multitude of off-square angles to seamlessly match the structure. Fabricating with stainless steel mesh allows for limitless flexibility to marry safety with style and functionality. The material can be shaped in multiple planes without compromising on strength, while its clean lines and obstruction-free form allows for creativity in design.

All Crimsafe security screens are Australian made and meet or exceed the requirements for compliance with various Australian Standards. Crimsafe exceeds the 1.4 tonne requirement of AS/NZS 1170.2 (Structural design actions, Part 2: Wind actions) by three times the standard, load testing to 4.2 tonnes. In addition, the 1.5mm x 1.5mm aperture of the mesh filters up to 62% of UV radiation, minimising heat gains and delivering energy efficiency. 

Forty-one bespoke triangular Crimsafe security screens were manufactured and installed by Sydney-based licensee, Wynstan. Crimsafe’s exclusive Screw-Clamp™ bites down on the mesh, holding it into the frame, which is then secured by tamper-resistant stainless steel screws. This vice-like grip transfers any weight and pressure to the frame, so the mesh remains intact. The unit specifically responds to the need for fall prevention, protecting patients and minimising falls.

With the help of stainless steel, Austin Hospital’s state-of-the-art facilities exude strength, security and style, challenging the convention of mental health rehabilitation and recovery. Opened in 2018, the Short Stay Observation Unit continues to deliver a peaceful and safe space for patients.



This article is featured in Australian Stainless Magazine issue 74, 2022. 

The seaside town of Terrigal on the New South Wales’ Central Coast has welcomed a new addition to its foreshore with a scenic walkway using stainless steel.

The long-awaited Terrigal Boardwalk connects the existing pedestrian networks of the Terrigal Beach promenade and The Haven, providing a safe and accessible route around the headland. The new attraction provides social, health and economic benefits for the local community, allowing visitors and tourists to enjoy the public space and ocean front area.

The project was jointly funded by the Central Coast Council ($2.9M) and the NSW Government’s Restart NSW Regional Growth Environment and Tourism Fund ($2.98M). The Terrigal Boardwalk’s construction included a restoration of the adjacent rockpool, a new disability-access ramp and pathway to link the rockpool and boardwalk.

Engineered and designed by Arup, the boardwalk structure has a 50-year design life, demanding a robust design to ensure durability and longevity. The elevated boardwalk is 277m long and 3m wide, and complements the surrounding natural environment with its blackbutt timber decking and stainless steel balustrading.

The construction comprises of a reinforced concrete suspended deck structure, a suspended structural steel viewing platform with fibre-reinforced plastic open mesh, sandstone block revetment and a retaining wall ramp structure. For the bridge deck, 7.5m is the typical span of the precast deck planks between concrete headstocks on steel tubular piles. Solid concrete deck planks were chosen to protect the timber boardwalk above from wave damage and minimise overtopping for users. The boardwalk sits approximately 4.5m above sea level to be just clear of wave crests during strong weather events.

Materials selection was critical to meet the specified design life, with consideration given to the foreshore’s high level weather events and salt exposure. Grade 316L stainless steel was specified for the balustrading on both sides of the boardwalk, ramp handrailing and the rock platform staircase.

While aluminium was considered during the design phase, stainless steel was chosen due to the material’s proven performance, corrosion resistance and durability in a marine environment, and aesthetic benefits in conjunction with the timber decking and handrail specified. In addition, a costing exercise conducted by Arup presented the long-term benefits of using stainless steel outweighing its additional upfront cost over aluminium.

Constructed by Land and Marine Group, the project involved a high level of collaboration between multiple local suppliers and service providers to meet the exacting demands of the specification. 

ASSDA Member Synergy Engineering was engaged to fabricate and install the stainless steel handrails, balustrades and stairs, spotted gum timber railing and the structural steel viewing platform. The project involved the stainless steel fabrication of 247 balustrade panels, 119m of handrail balustrade and an 8-step 1200mm wide staircase with fibre-reinforced treads. TIG welding techniques were used throughout the fabrication and installation process to ensure precision and a clean aesthetic.

ASSDA Member Atlas Steels supplied over 15t of 316L stainless steel, including 3402m of 30x8mm flat bar and 1656m of 70x10mm flat bar. The project was undertaken in the midst of the COVID pandemic, presenting a number of challenges with the supply of imported stainless steel material and shipping lead delays. As a result, Atlas Steels took the initiative to laser cut stainless steel plate to size and engaged ASSDA Member Decoware Australia to polish the material to specification. Starting with a coarse 80 grit through to a 400 grit finish, a surface finish of Ra <0.5 µm was achieved. The resourcefulness of local service and skill assisted in meeting the project program, delivering a resolution for the unprecedented challenges.

A small proportion of material was sourced from ASSDA Member Viraj Profiles, and ASSDA Member Vulcan Stainless supplied an additional 11t of laser cut 5mm, 10mm, 16mm and 20mm 316L stainless steel plate for the project.

Following fabrication, all stainless steel balustrade panels and handrails were electropolished by ASSDA Member Australian Pickling & Passivation Service and delivered directly to site for installation by the Synergy Engineering team.

The beautiful coastal boardwalk features a viewing platform, integrated seating, LED lighting and access to the rock platform. Offering uninterrupted views of the Pacific Ocean and beyond, the Terrigal Boardwalk is certain to meet the performance requirements of its design with its quality construction and use of stainless steel. 

The Terrigal Boardwalk officially opened on 14 April 2021, with its first steps taken by local crowds alongside the New South Wales Premier Gladys Berejiklian, Parliamentary Secretary for the Central Coast, Adam Crouch, Central Coast Council Administrator, Dick Persson, and the Council’s new CEO, David Farmer.
 
    

This article is featured in Australian Stainless Magazine issue 72, 2021.

Stainless steel lanterns now adorn the streets of Melbourne’s Chinatown, celebrating the cultural character of the longest continuous Chinese settlement in the western world.

Chinese lanterns are a symbol of Chinese culture worldwide, initially used to provide light and later adopted for religious worship, decoration and celebration. Traditionally made from silk or paper, the City of Melbourne recently evolved the Chinese hanging lanterns featured on Little Bourke Street from cloth to stainless steel.

In extensive consultation with the Chinatown Precinct Association, the City of Melbourne and GHD (Structural Engineers) reimagined the classic lantern with a detailed design that preserved the traditional aesthetic while examining a number of considerations. 

Durability and product life cycle were strong factors to reduce maintenance and regular replacement of the lanterns. Strength-to-weight ratio and resilience to local weather conditions was also important, with the completed design required to stay below 7kg to be viable for use on the existing catenary lighting system.

ASSDA Member Draffin Street Furniture worked closely with the City of Melbourne to bring the design to life, assisting with the materials selection and manufacturability of the lanterns. Two prototype lanterns were installed at the corner of Heffernan Lane and Little Bourke Street to test the design and seek feedback from local traders and the Chinatown Precinct Association.

Powder coated aluminium was initially selected as the design material however, stainless steel superseded the specification primarily for its strength and the ability for a thinner section of material to be used (0.6mm stainless steel sheet vs. 1.22mm aluminium sheet). In addition, stainless steel offered a more sustainable solution with a 25-year design life and little-to-no maintenance.

The final design resulted in a 700mm wide by 500mm high spherical lantern made from 316 grade stainless steel, powder coated with a luminous, metallic red colour. In Chinese culture, the colour red symbolises good fortune and joy. 

The lanterns were formed using laser cut 0.6mm sheet, with each panel formed into shape and fixed to a central aluminium frame. The custom-designed lanterns were manufactured by Draffin Street Furniture, and stainless steel material for the project was supplied by ASSDA Member Steel Color Australia.

80 new permanent lanterns were installed on the existing catenary lighting system, which was originally manufactured and supplied with the assistance of ASSDA Member Ronstan Tensile Architecture in 2009. The linear grid catenary suspended from the street’s buildings uses 316 grade stainless steel rectangular frames spaced equidistantly to hold the grid form, while permitting the suspension cables to connect to buildings at different heights depending on the availability of structural connection points. Designed to enhance the character of the precinct with Chinese lanterns and other iconography, the decorative and functional stainless steel catenary lighting system continues to perform structurally 12 years on since its installation.

Installation of the new hanging lanterns was completed at the end of July 2020. Brought to life using local design expertise and stainless steel, the lanterns maintain its symbolic heritage and will continue to provide a festive welcome to visitors for at least the next 25 years.
       

Image: @rayofmelbourne for @cityofmelbourne

This article is featured in Australian Stainless Magazine issue 72, 2021.

With a striking and innovative design evoking visions of the Singapore based Helix Bridge, stainless steel has formed an integral part in creating one of Sydney’s most exciting new structures.

Commissioned by Landcom as part of the Lachlan Line Precinct development project in North West Sydney’s Macquarie Park, the yet to be officially named cyclist bridge provides visual flair, safe accessibility, and excitement to the area. In an area with typically heavy traffic congestion, the project’s promotion of reduced car dependency creates a significant positive impact to the surrounding environment.

The design is the first of its kind in Australia, utilising a double helix arrangement with a varying diameter along its curving 178m length. While the design elements certainly lend themselves well to aesthetics, structural requirements dictated much of the overall shape. A steel truss arrangement is used, required for the long sections spanning the multiple roads below its footprint. The diameter of the spiral increases at the bridge supports and tapers along its span.  At its narrowest, it is 5.5m in diameter, and 7.8m at its widest.

Approximately 170t of 2205 grade duplex stainless steel was used, along with around 220t of structural mild steel. Due to the large quantity of material required, multiple distributors supplied material mostly on an indent basis, with some delivered ex-stock. ASSDA Members Midway Metals, Stirlings Performance Steels and Vulcan Stainless all supplied material, with the majority of plate (up to 80mm in thickness) produced by ASSDA Member Outokumpu, managed through their Melbourne office. 

A minimum 100-year service life with minimal maintenance (becoming increasingly common in the design of bridges) was a key criterion, particularly important for the hard to access structural components. From the beginning, 2205 duplex grade presented as an ideal material, thanks to its hybridised microstructural properties granting it superior mechanical properties to many forms of mild and stainless steel. 

Put simply, being stronger allows for thinner sections to be used or, alternatively, more scope for efficient design such as larger spanning or increased resistance to bending moments. Mild steel was retained  for the helical outer structure, and painted blue, which was a central design requirement. 

Arup proposed duplex stainless steel for the deck structure and wearing surface within the helix due its increased strength to weight  properties whilst maintaining high durability performance.   

Outokumpu played an instrumental role in advocating the use of the material properties of duplex grade at the early design and concept stages. Backed up by global materials experts and with a wealth of expertise in supplying stainless materials for bridges all over the world, Outokumpu aimed to provide a technical solution through the use of duplex stainless, rather than simply tender for the supply of material. “The use of duplex stainless steels in bridges around the world is becoming more and more the material of choice, so it was great to see Arup in Australia embrace it in its design”, said Con Logos, Vice President APAC at Outokumpu. “A special thanks to George Miech from my team for his tireless effort in the early stages, working closely with both Arup and RMS to have duplex stainless specified”. 

Outokumpu also assisted the fabricator and the end client, Transport for NSW, with expertise, advice, and preliminary procedures in welding the material, particularly vital with the thicker sections which require great care to ensure optimal material properties are realised in the weld and adjacent areas.

The bridge was fabricated in Sydney in four modules, which were trial assembled prior to being delivered to site, where the four segments were positioned and secured over the course of four weekends. Specially designed lifting assemblies were necessary to ensure the segments were not overstressed. 

As bridge design increasingly demands greater durability, aesthetic and creative licence and structural performance, stainless steel, of the duplex family in particular, presents a wonderful option now and into the future.

Photo credit: Landcom

This article is featured in Australian Stainless Magazine issue 71, 2021.

Located in the foothills of Perth, Aegis Amherst opened in July 2019 providing residential aged care in Canningvale, Western Australia. Set at the core focal point of the aged care facility presents a grand stainless steel balustrading ramp façade. 

ASSDA Member and Accredited Fabricator Balustrading WA were engaged by Absecon to fabricate and install a modern, safe, purpose-built ramp that would encompass strength and aesthetic attributes. 

The custom-designed ramp features an impressive 170 metres of grade 316 stainless steel tube. 

The handrails were manufactured from 50mm diameter stainless steel round tube. All stainless steel components were specified with a No. 7 high polish finish, supplied by several local suppliers including ASSDA Member, Stirlings Performance Steels. Mild steel flat bar was also used as the infill panels. Grade 316 stainless steel was specified primarily for its longevity, aesthetic appeal, and material strength. In addition, it is a durable and long-lasting alternative to competing materials.

Balustrading WA were heavily involved in the design brief and process, due to the extensive curvature inherent in the site. A range of advanced surveying techniques had to be used to ensure the balustrading was fabricated and installed correctly. This included using 3D image scans set into GPS grid location co-ordinates, rather than manual site measuring or templating as with more straightforward designs. As an example, the stainless steel support posts were scanned and fabricated individually to size to ensure correct fitment. In total, the project took just over 12 months to complete. 

The stainless steel ramp reflects the aged care’s cornerstone of their philosophy, by providing their residents with an environment that is comfortable and safe while delivering an aged care that helps them lead active, mobile and healthy lives.

This striking ramp facade continues to be the “hero” image for the facility, as stainless steel has once again delivered in compliance and material strength while fulfilling design and aesthetic needs.

     

Photo credit: Balustrading WA

This article is featured in Australian Stainless Magazine issue 70, 2020.

‘Limitless’ is the stainless steel sculptural creation of Gold Coast artist Ian Haggerty, whose concept was selected in a design competition by Bond University to celebrate their 30^th anniversary.

The 6.5m tall sculpture takes pride of place under the university’s iconic Arch and gleams in dignity and elegance from its 316L grade stainless steel construction. Inspired by the limitless possibilities created by education, the sculpture features a world sphere at its centre with four overarching wings representing the four pillars of learning: Learning to know, learning to do, learning to live together, and learning to be.

Reflection was also a key concept in the sculpture’s design, with mirror polished stainless steel the unrivalled material choice in bringing together the alumni and future students to inspire and signify that there are no limitations to education when it comes to gender, age, race, or religion.

In a nod to celebrating local fabrication, the artist engaged Burleigh-based ASSDA Member and Accredited Fabricator Atlas Stainless Balustrade & Fabrications to fabricate and install the 1.5t sculpture. 

Stainless steel rings were laser cut in various sizes from 100kg of 5mm mirror polished plate and welded together to create the intricate bubble pattern featured in the top section of the four wings. The bottom sections were fabricated from 400kg of plasma cut plate, with 1mm sheeting used to cover the bottom eight sides to allow for the chemical etching of over 26,000 Bond University graduates in homage of their educational achievements.

The Atlas Stainless Balustrade & Fabrications team also fabricated the base structure, and sphere and wing supports from mirror polished pipe to bring together the pre-constructed world sphere and its overarching wings. The fabrication process involved the team using their in-house plasma cutter, CNC bandsaw, CNC section roller and in-house polishing equipment both by machine and hand, and specialist welding techniques.

The project took over six months to complete and the structure was installed using two cranes, joining the university’s existing landmarks as a focal point of the state-of-the-art campus landscape. Special lighting effects were also installed as part of the sculpture to highlight its key features at night and shimmer in the surrounding water of the lake fountain.

‘Limitless’ was unveiled in May 2019 to celebrate the university’s 30-year milestone and remains a legacy piece for Bond University.  

This article is featured in Australian Stainless Magazine issue 69, 2020.

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.

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.

Setting the benchmark in boutique luxury and innovation using stainless steel is Brisbane’s Emporium Hotel.

Developed by the Anthony John Group, The Emporium Hotel opened in July 2018. Nestled in the premier lifestyle and cultural precinct of South Bank, the 143-suite hotel is turning heads with its exquisite interior design, bespoke handcrafted features and luxurious facilities.

Stainless steel was the material of choice for the five-star hotel and selected for its quality, opulent aesthetic and luxury appeal. Over 5.5 tonnes of grade 304 stainless steel sheet, 1.2mm thick in a No. 8 mirror finish was used throughout the five-star hotel and supplied by ASSDA Member Fagersta Steels. 

ASSDA Member and Accredited Fabricator, Langford Metal Industries, was engaged to laser cut the mirror finish material to bring the developer’s trademark design to life, which was installed by Thump Architectural.

The frangipani inspired pattern represents the Queensland theme and character, and the laser cut stainless steel prevails throughout the hotel on mullions, sliding doors, external panels, columns, cabana suites surrounding the 23m infinity edge pool – almost anywhere and everywhere, serving both a functional and decorative purpose.

A remarkable feature of the hotel is its rooftop bar on the 21st floor, The Terrace. Presenting panoramic views of South Bank Parklands, the Brisbane River and the city skyline, The Terrace maximises the warm Queensland weather with two retractable roofs offering full, partial or no exposure.

Measuring 7.5m long, 2.1m wide and 50mm thick, the ceiling of the first retractable roof features the impressive frangipani stainless steel design. The sliding panel is a composite structure incorporating insulation and structural members which are clad top and bottom with mirror polished stainless sheet. For structural purposes, the panel was shaped into a shallow moon profile to form the roof’s arch. When retracted, a second roof made of glass is revealed, which is also retractable for a complete outdoor rooftop experience.

The stainless steel ceiling and surrounding elements complement the rooftop bar’s sub-tropical luxe vibe with ceiling-to-floor glass doors, lush greenery, and white backlit onyx floor tiles and bar.

Photo Credit: Emporium Hotel

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.

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.

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.

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

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.

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.

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 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).

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).