Specifying Stainless Steel for Luxury Beachside Homes


Posted 31 October 2005

Stainless steel enjoys a strong and enduring reputation for visual appeal and structural integrity in a wide range of applications. This broad appeal has made stainless steel an ideal choice for value-adding luxury homes on Sydney’s northshore.

Spiral Staircase - Collaroy
One particular luxury home overlooking the beach at Collaroy was owned by former rugby league test captain Brad Fittler at the time. The home featured an external steel spiral staircase. However, its close proximity to the surf had caused the painted staircase to corrode in less than 12 months of installation.

Salt deposits had accumulated on the structure, causing the staircase to rapidly corrode in the harsh coastal environment.

Builder, Binet Homes commissioned ASSDA member, DJQ Industries to fabricate and install a stainless steel spiral staircase that could cope with the sustained salt exposure inherent with coastal applications.

DJQ Industries fabricated the new staircase out of grade 316 stainless steel supplied by ASSDA Major Sponsor, Fagersta Steels. The staircase was welded into sub-assemblies and electropolished by Regents Park Electroplating on completion of fabrication prior to installation on site.

The corrosion resistance of stainless steel in this environment and exposure to natural rain washing will mean this installation will have a long service life with minimal maintenance.

Pool with a View - Palm Beach
Substitute your morning coffee for a dip in this luxury home pool with a spectacular eye-opening view of northern Sydney’s beautiful Palm Beach.

ASSDA member DJQ Industries was contracted by Bellevarde Constructions to supply and install stainless steel balustrades, pool edging, fence and other household fittings.

ASSDA Major Sponsor Fagersta Steels supplied grade 316 stainless to DJQ Industries for the $200,000 project. The project was fabricated to meet all building and structural codes with finishes suitable for a marine environment.

The unique pool edge detail provides a less obtrusive mounting for the glass and stainless steel was used extensively in the construction of framework for the pool platform steps. Stainless steel items for the house included a chimney cowl, chimney cap, downpipes, trench type floor drains to bathrooms and sliding door tracks to all north facing walls on two levels.

The extensive use of stainless steel in this luxury home highlights the importance of specifying stainless steel for maximum corrosion resistance and enduring visual appeal.

This article featured in Australian Stainless magazine - Issue 33, Spring 2005.

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Cleaning and Protecting Stainless Sculptures


Posted 30 September 2004

"Windhover" is a dramatic stainless steel sculpture created by the late Lenton Parr, located on the eastern foreshore of Port Phillip Bay in Sandringham, Melbourne.

Unveiled in December 2001, the sculpture's vertical lines and arcs are evocative of the yachts often seen sailing out on the Bay.

However, two and a half years of zero maintenance and exposure to salt spray from the bay have taken their toll, turning the surface of the stainless steel a blotchy brown.

Called tea staining, it's caused by deposition of salt on the surface which is then trapped in the crevices of the brushed finish.

Regular reactivation by rain has perpetuated a corrosion cycle leading to quite rapid and severe surface staining.

The problem was how to clean the sculpture and then to ensure that it would remain protected from tea staining in the future.

Conventional weld pickling products containing hydrofluoric acid are very aggressive and risk damage to or discolouration of the surface.

Strong acids may also create an environmental and safety hazard when used in such a public place.

Many cleaning formulations are available based on phosphoric, sulphamic, oxalic or nitric acids. They have various degrees of handling and disposal restrictions.

The formulations may also contain mid abrasives and wetting agents/detergents to aid the cleaning process.

In July 2004, ASSDA Member, Revolution Advanced Metals and Materials, used a cleaning paste based on a moderate concentration of phosphoric acid which is relatively safe to handle.

Inadvertent skin contact by this product does not cause the burning and possible ulceration associated with strong concentrations of nitric and hydrofluoric acid preparations.

The cleaning product was brushed on and left to react for 3-4 hours. The brown tea staining gradually disappeared.

In some particularly bad sections a second application was necessary to completely remove all traces of the staining, but it left a completely blemish-free surface.

In this case, residue from the cleaning product was simply washed away with water. In other cases, however, check with local authorities for correct disposal procedures.

One of the problems when washing stainless steel with water is the streaking caused by uneven drying.

This was very noticeable on the sculpture.

Also, because it is unlikely that ongoing regular cleaning will occur, it is also important to limit the access of chlorides to the surface. Otherwise the staining problem will recur.

To overcome both these problems, a water-based protective product with oils and non-ionic surfactants but no phosphates was sprayed on and wiped over.

After polishing with a dry cloth all streaking vanished. It left an invisible film that stopped further streaking and fingermarks.

Best of all, it brought up the lustre of the brushed finish, and left Windhover looking as good as the day it was made.

Regular re-application should maintain the finish and help prevent tea staining in future.

Correct design, fabrication and on-going maintenance will all assist in keeping stainless steel sculptures and other structures erected adjacent to the coast in good condition.

Words and images courtesy of Jim Picot, Revolution Advanced Metals & Materials.

This article featured in Australian Stainless magazine - Issue 29, September 2004.

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Fishing for compliments: stainless steel fish art


Posted 1 September 2004

Steve Mason and his mate were sitting on a couch one day drinking beer when Steve came up with the idea of using stainless to turn his mate's wall into a work of art.

Steve's mate had just purchased a new unit with a large sea green wall. As the pair sat staring at the wall, Steve got an idea that would change his life ..... and complement his mate's wall.

"He wanted something to hang on the wall to break up the space, so I made him a school of eight mackerel," Mason said.

A boilermaker from Woodford, Queensland, Mason loves to go fishing and is inspired by pictures of fish in magazines, but soon found that choosing the right material was important.

"I heated some stainless to colour it and left it aside for about 18 months. When I found it again and noticed the colours had not faded significantly, I decided to make fish out of 316."

"The colours that appear and the sheen and lustre of 316 really suits fish" Mason said.

Working closely with fish photos and sketches, Mason tries to capture distinguishing features of each species including bream, barramundi, whiting, coral trout, marlin and many more.

Mason sources stainless steel scrap from ASSDA member Smorgon Steel Recyclers (Metalcorp, Hemmant - Queensland) and purchases grade 316 stainless steel sheet from ASSDA member Midway Metals (Queensland) to create many of his art sculptures.

Steve Mason now works full-time creating stainless steel fish art under the trading name of Masosa and sells his art through mailorder catalogue and in person at the Eumundi Markets, Queensland every Saturday morning.

Ranging from $145 to $3,000 in price, Steve's art now complements walls in cafes, fish and chip shops, art galleries and beside home pools. Best of all, it is the perfect present for one wall (or every wall) of any fishing fanatic.

This article featured in Australian Stainless magazine - Issue 29, September 2004.

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Cleaning of exterior stainless steel


Posted 1 May 2004

The visual performance of outdoor stainless steel depends on five interrelated factors:
• Surface finish - smooth and clean and free of crevices.
• Grade selection - appropriate for environment.
• Good design - rain washing and uniform draining.
• Maintenance program - regular cleaning.
• End user expectations. This technical article provides suggestions on a maintenance program for cleaning of exterior stainless steel, together with some recommendations for remedial action if stains occur beyond regular maintenance or where such maintenance has not been performed.

Maintenance: routine removal of grime

Stainless steel holds its appearance best if it is washed regularly. When washing use soap or detergent or 1% ammonia solution in warm, low chloride water with cloths or soft brushes to avoid scratching the surface.

Smears will be reduced if the surface is dried afterwards. This treatment applies to bare stainless steel but care should be taken with coloured surfaces.

Coloured and very smooth finished (eg BA or No. 8) surfaces subjected to excessive brushing or rubbing may lose gloss or even become scratched. Bleaches are not recommended.

Simply wiping with a damp cloth is not adequate as it smears corrosive deposits without removing them.

Table 1 from the ASSDA ‘Tea Staining’ Technical Bulletin provides a guide to the recommended frequency for cleaning exterior stainless steel. This Bulletin is available for viewing or download from ASSDA’s website.

Grease, oily films and other organic contamination

Oils and grease may be removed by alkaline formulations or hot water and detergents or, if necessary, by hydrocarbon solvents such as alcohol, acetone or thinners or eucalyptus oil. In all cases the surface should be rinsed with clean water and preferably dried.

For directionally grit polished finishes, wiping along the polish direction with very hot clean water and a soft, absorbent cloth is a good final step to reduce smears.

Heat from a hair dryer or glue gun may soften adhesive remnants from labels or protective films for removal.

After exposure to UV degradation from sunlight, adhesives may require similar treatment to grease stains or even abrasion, with the probability of a bright or scratched spot.

Adherent Scales and Mortar

Adherent scales and mortar may be removed chemically but NOT using chemicals containing chlorides.

NEVER use brick cleaning liquids that contain hydrochloric acid. Hot 25% acetic acid (vinegar) or warm 10% phosphoric acid are effective in removing hard water scales and dried mortar splashes.

Following the acid wash, the surface should be neutralised with dilute ammonia or sodium bicarbonate solution, rinsed and dried.

Remedial Work

The brown surface stains that can occur on stainless steel during atmospheric exposure are simply cosmetic rust stains.

This brown ‘tea staining’ on stainless steels will not progress to potential structural damage as could occur with a carbon steel structure.

The procedures outlined below may enable you to remove the tea staining. However, if the progression of damage is beyond these recommendations it is advisable to employ an experienced contractor.

Cleaning Rust Stained Flat Surfaces

Early action after the onset of tea staining is desirable, before the appearance of the underlying surface is changed.

If the surface is pitted, then it is probable that it will require mechanical repolishing. After mechanically cleaning off tea staining, it is preferable to passivate the surface by using a nitric acid gel or, if the item is portable, by immersion in a nitric acid bath. For marine exposures, passivation is very strongly recommended.

In contrast to other acids, nitric acid is a strong, oxidising acid cleaner and has the added advantage that it is a passivating agent.

The Nickel Institute has suggested that rust may be removed by the use of a 10% phosphoric or oxalic acid followed by a 1% ammonia solution neutralisation and then a water rinse.

Alternatively a mild acid based cleaner such as sulphamic acid (used in some saucepan cleaners) can be used with some care to avoid local changes in appearance. NEVER EVER use hydrochloric or sulphuric acids.

There are also proprietary chemical cleaning treatments often based on citric acid or other chelating compounds. Although these agents passivate in the sense of removing free iron and other foreign matter, they do not augment the surface oxide film.

Use of liquid acids on site is generally unsatisfactory as contact time is short and the acid may run off and damage adjacent components.

Unlike the hydrofluoric acid pickling process used after welding, a nitric acid passivation process does not normally change the surface appearance of stainless steel, although it may cloud a mirror polished surface. Careful trials on inconspicuous areas are recommended prior to full scale cleaning.

Electropolishing is also used by some contractors to smooth rough edges and both clean and passivate the surface. It can be carried out on site or, more usually, in purpose-built tanks.
Afterwards – prevention of recurrence

If tea staining has occurred, one or more of the five factors outlined in the introduction have not been considered carefully enough when the structure was designed and/or built.
To improve the structure, the following steps may be taken to prevent recurrence:
• Increase the frequency of maintenance.
• Improve the surface finish - mechanical polishing and chemical treatment on-site.
• Alter the design of the structure - redesign and replace the affected part of the structure.
• Improve grade selection - replace the structure with a more suitable grade of stainless steel.


ABOVE: A successful stainless steel installation in an outdoor application.

If consideration of the aforementioned steps indicates an uneconomic result, the stainless steel can be painted.

Paint systems using lacquers and polyurethane top coats are available and have been used successfully, but care and understanding is required.

Painting the stainless steel is a step that should only be used as a last option as it is irreversible.

This technical article was published in Australian Stainless Issue 28, May 2004. It is an extract of a Technical FAQ on ‘Exterior Cleaning of Stainless Steel’.

For technical support and advice contact ASSDA on 07 3220 0722 or email assda@assda.asn.au

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Brisbane RiverWalk: Floating in Stainless

Posted 28th February 2004



Brisbane residents can now walk on water with the completion of the Brisbane City Council's RiverWalk floating walkway.

Stainless steel is at the heart of the 850 metre-long, 5.4 metre-wide pontoon system that effectively connects the city and the inner suburb of New Farm.

The pontoon structure, positioned 35 metres from the riverbank, has been designed to allow people to experience the feeling of being on the river - of literally walking on water.

Brisbane Lord Mayor Tim Quinn said "Brisbane is now truly Australia's River City as we're making greater use of our river system than any other state in the country.

"Completion of this vital section of RiverWalk will also have the added benefit of enhancing the city's public transport network by offering immediate access to interchanges including City Cat, ferry services, bus and rail."

Made up of a state-of-the-art pontoon system that wraps around the shoreline, it boasts world first technology that was designed and engineered in Queensland.

ASSDA supported the project by responding to more than 40 enquiries for technical assistance for the Brisbane City Council project.

Fabricating the Top-Side Structure

ASSDA member, Pryde Fabrication, supplied 35 tonnes of handrails and posts to the $13.5 million project and was instrumental in fabricating many of the environmental design elements featured on the walkway.

Pryde produced 60 individually curved handrails to create a visual effect of the ebb and flow of the Brisbane River, whilst support posts and the straining posts that holds all the load incorporates a distinct 'mangrove' design.

Grade 316 stainless steel was used throughout the fabrication of handrails, balustrades and staunches with a smooth surface finish enhanced by electropolishing.

RiverWalk Stainless Steel - ASSDA Members Suppliers

Pryde Fabrication Top-side structure - handrails, balustrades and staunches
Arminox Australia Reinforcing bars in pontoons
Ronstan International Cables and rigging materials
Sandvik Stainless steel supply to Pryde Fabrication
Atlas Speciality Metals Stainless steel supply to Pryde Fabrication
Condamine Wellscreens Electropolishing services to Pryde Fabrication
Johnson Screens Stainless steel supply to Pryde Fabrication
Tom Stoddart Pty Ltd Supply of stainless steel pole guides

Reinforcing the Pontoons

The key to RiverWalk's extended lifecycle was the use of stainless steel reinforcement by ASSDA member, Arminox Australia in the design of the 287 floating pontoons.

Most concrete reinforcing uses carbon steel, however, in marine structures where the material is exposed to chlorides in the salt water, it can corrode and cause the concrete to crack and deteriorate over time.

Arminox supplied 140 tonnes of reinforcing bar material, cut and bent to the customer's schedule in 10, 12 and 16 mm diameters.

Using specialised machinery, Arminox was able to save Brisbane City Council thousands of dollars by cutting out and tying a number of lap joints with a 40mm diameter overlap.

By reducing the thickness of concrete cover the Council saved two cubic metres of concrete per pontoon.

This initiative resulted in a lighter pontoon that contributed to increased buoyancy and lower costs for the Council.

With a total of 450 kg per pontoon, tighter tolerance control meant enhanced low material wastage.

Stainless reinforcing builds corrosion resistance into the concrete and durability has been proven over many decades.

World Class Achievement

ASSDA congratulates all members who supplied stainless steel to the Brisbane City Council's RiverWalk floating walkway, naming the project "a Queensland world class achievement designed to last 100 years with minimal maintenance".

ASSDA Executive Director, Richard Matheson inspected the 850 metre floating pontoon system after its official launch in December 2003 and congratulated the Brisbane City Council on a durable feature that would only have been made possible with stainless steel.

"The RiverWalk is a world class achievement designed to last 100 years and to achieve this aim 181 tonnes of stainless steel was specified for its durability in not only handrails, posts and cabling but also for reinforcing in the pontoons," Richard Matheson said.

"Stainless steel is at the heart of the RiverWalk project because of the material's non-corrosive properties and excellent presentation despite harsh environments," said Mr Matheson.

The RiverWalk will now provide direct riverfront access for around 20,000 walkers, cyclists, joggers and rollerbladers everyday.

RiverWalk Stainless Steel Specification Checklist

  • 850 metre floating walkway
  • 287 floating pontoons
  • 181 tonnes of stainless steel
  • 20 km of stainless steel wire
  • 2,534 kg of stainless steel wire cable
  • 135 kg of stainless steel rigging fittings
  • 1,800 linear metres of handrail
  • 1,750 support posts/staunches
  • 60 individually curved panels
  • 140 tonnes of reinforcement bars
  • 35 tonnes of handrail and posts

This article featured in Australian Stainless magazine - Issue 27, February 2004.

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Council Solves Fishy Problem with Stainless


Posted 30 November 2003

Coastal areas are popular sites for recreational fun and fantastic fishing. However, the City of Albany in Western Australia had one major problem to deal with - fish waste in the nearby waterways

Local fishermen were cleaning and filleting fish and disposing of the waste overboard. This waste not only stagnated in the water for days, but also attracted seals and stingrays that can become aggressive when feeding.

Faced with a situation of replacing what was a kitchen sink on rusty legs in the water, the Council turned to local ASSDA member, Austenitic Steel Products, to design and fabricate an innovative new stainless steel fish cleaning station for the Emu Point Boat Ramp.

The circular fish cleaning station is believed to be the first and only one of its design currently available in Australia and measures 1400mm in diameter and 1100mm high.

Produced in 316 stainless, the compact design allows six operators at a time and provides a safe environment with no corners or sharp edges.

All plumbing is internal with access only through a hatch on the face of the cone and fitted security locks. Waste water falls to the centre of the table and flows through a circular screen into a collection hopper before entering a two inch waste pipe concealed in the centre.

Initially, the station requires manual removal of offal, but when funding and municipal sewerage is available, the table can be modified to incorporate an automatic processor to pulverise offal into disposable liquid waste.

Albany City's $13,000 station project has generated interest from other Councils and looks set to appear in local boat launching areas, coastal caravan parks and seaside fishing locations throughout Australia.

This article featured in Australian Stainless magazine - Issue 26, November 2003.

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Specifying Stainless for a Salt Air Setting


Posted 1 July 2003

Architect Jan Jensen was a consultant to Brisbane City Council on the design of the Brisbane Riverwalk, currently under construction. The walk will take pedestrians from the CBD to the inner suburb of New Farm along the river.

At this proximity to Moreton Bay, the water is brackish and the air salt-laden - it is destructive to most construction materials. Corrosion-resistant stainless steel was chosen for this landmark project to deliver the 100 year service life required by the asset owner.

The structure consists of floating pontoons, reinforced with 316 stainless steel deformed bar. There are stainless steel balustrades and light poles and a suite of stainless street furniture.

Jensen describes the process of specifying the correct finish, including gaining a theoretical understanding and producing prototypes:

The Starting Point
As a key parameter of design responsibility 'value for money' the decision to use stainless steel was an easy one. Our rationale was: "It doesn't corrode and our work is in salt-affected air; it lasts forever; it is low maintenance; it will save us money and keep on looking good."

We needed a specification to let contracts for the manufacture of street and riverscape elements. Writing a specification required describing and reproducing the manufacturing process exactly to get reliable, predictable, consistent and economic results.

Our research took us to ASSDA's timely seminar on the fifty most frequently asked questions about stainless steel, where we were able to ask about tea-staining and how to avoid it.

Then we talked to manufacturers. The answers to our questions about surface roughness and the finishes available made us realise there were variations within the industry and we needed to define our requirements with scientific precision. Specifically, we needed to know the surface roughness (Ra) in microns (µm), as the labels 2B, No. 4 and so on refer to the method used to achieve the finish and comprise an Ra range.

Building Prototypes
We concluded that to write our specification we needed to build the product first to set it within the theory and the 'standard range of common industry manufacturing practice'. We commissioned prototypes of a balustrade and a light pole then the furniture suite for the Riverwalk: seats, bollards, bins, lights, sign posts and drinking fountain.

Forge Brothers Engineering produced the prototypes. It drew on the expertise of ASSDA and its members University of Queensland Materials Performance, 3M Australia, Heat & Control, Condamine Wellscreens, Ronstan International as well as AbrasiveFlex and Dana Ridge.

We soon realised that:

> The common system of finish grades is not a measure of surface roughness, eg the Ra of No. 4 finish products measures anywhere from 0.45 to 0.8µm depending on product form and supplier. Typical Ra for sheet is 0.3 to 0.4µm while it is not unusual for other products such as flat bar to be rougher. Thick plate, thin plate (sheet), tube, flat bar and hollow bar are manufactured by different processes which produce different finishes. The surface finish changes in hot rolled plate and gets smoother as the plate reduces in thickness.

> Ra meters were not commonly used in the industry although their use is growing.

> All abrasives aren't the same. Wear and tear and pressure make a difference. We tested non-woven abrasive belts, Trizact belts, air wheels and silicon carbide.

> The electro-polishing industry uses a variety of chemical baths and voltages.

Towards a Specification
In arriving at our specification we learned:

> Best practice calls for a finish below 0.5µm combined with electro-polishing to eliminate sulphides and increase the chromium content of the exposed surface.

> Wet blasting at low air pressure levels with a water and abrasive bead mix provides a consistent surface finish and economically removes surface variations ready for electro-polishing. This avoids the unexpected rise in roughness which can occur when electro-polishing removes microscopic peaks, previously flattened by mechanical polishing, to uncover underlying pits.

The proof that our specification works can be seen on the Brisbane River. After twelve months in a salt air environment our prototypes are still looking clean and new.

Words by Jan Jensen.

This article featured in Australian Stainless magazine - Issue 25, July 2003.

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Stainless promotes safety at sea


Posted 1 July 2003

Vessel pictured is typical of those that use this type of fire damper.

A fire at sea is a traveller's worst nightmare. To guard against such a disaster there exist stringent safety standards, maintained through a process of testing and certification. The pre-eminent authority is Lloyd's Register of Shipping, an organization founded in 1760 to inform underwriters and merchants about the condition of the ships they insured and chartered.

Today, certification by Lloyd's Register is a significant commercial achievement. Earlier this year, Lloyd's issued a 'Certificate of Fire Approval' to a new stainless steel fire damper for use on merchant and passenger ships. Grade 316L stainless steel was used in the dampers because of its dual resistance to high temperatures and corrosion in a demanding marine environment.

In tests conducted by the Warrington Fire Research Group at CSIRO's North Ryde facility, the single-blade and multi-blade units made by ASSDA member Unique Metal Works were subjected to 900+¡C temperatures for an hour. They successfully prevented fire spreading across a nominal Class A-60 deck, in compliance with Lloyd's Register Rules and Regulations and the International Convention for the Safety of Life at Sea.

The dampers were developed and fabricated by the Perth company, which utilises stainless steel to produce a variety of safety and environmental control equipment and other products. They are installed to isolate fire zones on a ship, for instance, where ventilation or air conditioning ducts pass from one zone to another. The controls can be electric or pneumatic depending on the ship's system. The blades are designed to remain open while the pneumatic power to the control actuators is maintained and to close down when there is a disruption to the supply. Under test conditions, this took 4 seconds for the 150mm x 150mm single-blade damper and 35 seconds for the 900mm x 900mm multi-blade type, well below the 90 seconds allowed.

UMW's certification is an example of Australian innovation being recognized internationally for high standards of materials, workmanship and construction.

This article featured in Australian Stainless magazine - Issue 25, July 2003.

Photo courtesy of Austal Ships Pty Ltd. Vessel pictured is typical of those that use this type of fire damper.

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Mirror Mirror on the Water

Stainless Steel Fish Bar


Posted 31st March 2003

Development of Melbourne's Docklands Precinct has inspired an exciting range of creative architecture, featuring a diverse selection of building materials.

Special finish stainless steel enhances the facades of the prestigious NewQuay follies on Victoria Harbour promenade. The Fish Bar folly, clad entirely in blue mirror stainless steel, brings life to the water's edge by combining public convenience with creativity to produce a unique example of urban art.

The design is the result of a successful collaboration between the developer MAB Corporation, SJB/FKA architects and students from the upper design pool of RMIT's School of Architecture, which ran a design competition.

The winning concept, by students Sherry-Ann Kwok and Jessica Liew, was deemed to successfully unify and integrate art and architecture into a commercial or retail environment. The underlying aim of the follies was to create sophisticated architectural forms that break up the hard edge against the water and create defined destinations as people move around NewQuay.

Blue mirror stainless steel from ASSDA member Rimex Metals was chosen as it evokes suggestions of frozen water and adds bold, bright colour to the building, which consists of an arrangement of raking, interlocking planes. The physical properties of stainless steel and its corrosion resistance in this salt-water environment make the material a logical selection.

The Colouring Process

As coloured mirror stainless steel is generally only produced in grade 304, a special mill run of 316 material was produced by Rimex UK to fulfill the architects' requirements for corrosion resistance and colour continuity.

Grade 316 stainless steel sheets were polished to a mirror finish before being coloured. In the colouring process, the stainless is immersed in a chemical bath to closely control the generation of the chromium-rich oxide film. This clear oxide film is present in all stainless steel and is the key to its excellent corrosion resistance.

By varying the film's thickness, a range of colours is produced, the same way that oil floating on the water's surface produces a rainbow effect. No dyes or pigments are used: the colour is due entirely to the physics of light distorting as it bounces off the stainless steel surface and back through the oxide layer.

Construction

Commercial builders, Icon Construction Management, were commissioned to construct the building. There were some challenging hurdles as the building is perched half on the pier and half over water supported by pylons.

Construction was performed from a barge with the use of booms and scissor lifts from the wharf.

Fabrication of the Rimex blue mirror sheet into cladding panels and their installation was performed by Alustain Fabrications, a Melbourne firm specialising in architectural stainless steel cladding.

The interlocking panels were pressed into individual pans and attached to a waterproof plywood substrate before fixing to a top hat section. The complex design called for almost every panel to be unique.

Together they form a weatherproof barrier capable of withstanding demanding coastal conditions. Unlike most faades, the stainless steel cladding was installed at the beginning of construction, enabling fixings to be concealed with only a 1-2mm margin between panels. ASSDA member, Fagersta Steels Pty Ltd, supplied the stainless steel for the project.

The Fish Bar folly contributes to the mix of open space experiences aimed at meeting the diverse needs of residents and visitors. The contemporary design and material selection demonstrate stainless steel's potential for integrating architecture and urban art.

Words: Neil Lyons, Photos: Anna Joske
This article featured in Australian Stainless magazine - Issue 24, March 2003.

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"Dancing Wall" - Colour & Movement in Stainless


Posted 1 March 2003

To symbolise the wetlands landscape of the Nundah area in Brisbane’s north, sculptor Daniel Della Bosca sought out materials which best convey the fluidity and reflectivity of water and the reedy texture of waterside vegetation.

His choice was 316 stainless steel, finished with specialised surface treatments, combined with translucent blue glass and earthed in basalt.

“Dancing Wall” was commissioned by Brisbane City Council (BCC) as part of its program of Suburban Centre Improvement Projects (SCIPs) which aim to improve economic vitality, focus on community life and enrich local activity. The Nundah SCIP is one of the larger projects in the scheme with a budget of $2.5m.

The artwork is a sculptural balustrade set on the hilltop at the corner of Buckland Street and Sandgate Road. Its design symbolises the local environment which was once rich in waterholes and is now the focus of BCC and Wildlife Preservation Society rehabilitation initiatives.

According to Della Bosca, the piece is not just about the past: the materials and design provide an inspirational link to the future.

The client has expressed satisfaction with the completed project, with Deputy Mayor Councillor Quinn commenting that it fulfills the Council’s objectives of “good design and creative activity to build a prosperous city.”

FABRICATION

“Dancing Wall” was fabricated by Della Bosca in grade 316 stainless plate, flat bar and rod supplied by ASSDA member Austral Wright Metals. It houses five panels of slumped and toughened ‘azurelite’ glass, made by artist Shar Moorman, internally illuminated by concealed LED lighting.

Most of the structure was fabricated from rolled stock to bring an organic quality to the design. The intricate forming was carried out by local firm BJR Metal Rolling & Pressing who specialise in rolling compound curves.

SURFACE FINISH

Integral to the design are the surface treatments which suggest reed and water textures. ASSDA member Australian Industrial Abrasives helped to investigate the products, appropriate tooling and techniques to achieve the desired effects. The finishing on larger areas was completed with a Dynacushion on a variable speed sander polisher, using abrasive belts in a range from P80 to P150 Zirconia/Alox and finishing with 3M Blue Scotchbrite. The tighter, more intricate areas were finished using a Dynafile and various contact arms and the same range of abrasive belts.

An easily achievable, cost-effective maintenance schedule using an activated surfactant cleaner quarterly and a passivation gel as required has been implemented by Brisbane City Council.

The cleaning agent removes oil, grease and dirt, and also removes surface free iron which may cause discolouration or more serious corrosion.

This step is followed by a passivation gel which chemically generates the chrome oxide passive film on the surface to enhance corrosion resistance for stainless steel installed in high corrosion environments.

ARTISTIC POSSIBILITIES

Della Bosca says the qualities of stainless steel can best be conveyed by allowing the material to interact with light. “As fabricators well know it is easy to ‘muddy’ the surface of stainless, but if care is taken and correct procedures followed, the metal can give opportunities to a surface finisher.

“I work with the stainless to allow it to speak of more than itself. This is much more important to me than trying to force a finish.”

This article featured in Australian Stainless Issue 24 - March 2003.

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Hooked on Stainless


Posted 1 March 2003

Grade 316 stainless steel offers superior corrosion resistance and has become the norm for architectural applications within 5km of the coastline. Another natural use for grade 316 stainless is in boating and marine sports gear, which has to withstand the corrosive effects of salt water.

Deck fittings and equipment made in 316 stainless are stronger and more durable than most alternatives. Their lifespan is further enhanced when kept clear of salt encrustations, grease and dirt. This is facilitated by a very smooth surface which doesn't present miniscule pits and crevices where corrosion can begin.

An example of grade 316 being used to good effect is the Cannon Rod Holder by ASSDA member Emro Products. For the benefit of the non-fisherperson, a rod holder is mounted onto the side or deck of the boat to hold the fishing rod and free up both hands for other tasks.

Using several rod holders when trolling allows more lures to be placed and the area covered is increased if the holders are angled at 90 degrees to the sides of the vessel.

The Cannon is made from highly polished grade 316 stainless steel, rigorously tested to ensure a durable and reliable product. It is fully adjustable so that the rod can be positioned as desired. Being detachable it can be easily cleaned and is less vulnerable to theft.

The D locking mechanism in the base of the shaft ensures that it attaches securely and cannot be accidentally released, losing both valuable fishing equipment and the catch.

The rod holder is manufactured in two lengths, 145mm long with rubber buffers on either end and 300mm long with a pin in the end to suit a gimbal.

This article featured in Australian Stainless magazine - Issue 24, March 2003.

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Stainless Braves the Elements


Posted 1 December 2002

Advanced engineering solutions are required to handle conditions found on offshore drilling and processing platforms. The saltwater environment is highly corrosive, the flare presents extremes of temperature and the force of winds and currents is constant. The most durable and reliable materials need to be employed, which is why stainless steel plays and important part.

An impressive project making use of stainless' strength and corrosion-resistance is the Bayu Undan Gas Project in the Timor Sea, 5OOkm north of Darwin (pictured). Here, stainless steel is used to line the 18" pipelines between the processing platform and the wellhead platform 8km distant and in thousands of metres of pipes throughout the installation.

SPECIALIST BRIDGE BEARINGS
Stainless steel and high nickel alloy bearings support various bridges, including a 225m long bridge from the drilling platform to the flare. The bearings have been designed by specialist engineering and manufacturing firm Ludowici Ltd of Sydney, working closely with the project consultants TIGA JV of Perth. The bearing shown above is mirror polished to slide ±600mm while supporting a 900 tonne load, with operating temperatures up to 220°C due to the flare. In addition to continuous wave action, the bearing is designed to withstand 160 tonnes of transverse load due to gale force winds during tropical cyclones, as well as "bumps" during installation.

Bayu Undan is a project of Phillips Petroleum Company Australia Pty Ltd. Gas and liquid hydrocarbon reserves were discovered in 1995. It is estimated that the 25km by 15km field has a 25 year life and reserves of 350-400 million barrels of hydrocarbon liquids and 3.4 trillion cubic feet of gas. Work on the site is proceeding with full commercial production due by 2004. The first phase of the development, representing a US$1.4 billion investment, involves production and processing of wet gas. A second phase is planned to harvest the field's gas reserves.

Ludowici became involved in Bayu Undan in mid 2001, when it was chosen to design, manufacture, test and supply eight highly complex stainless steel pot-type bearings.

The design team drew on technical expertise of the Australian Stainless Steel Development Association and the Nickel Development Institute to produce a suitable design.

BUILT TO WITHSTAND WIND, WAVES AND WATER
The brief presented some unique challenges including massive steel superstructures requiring high-strength low-friction supports, to be left maintenance-free in a remote, aggressive tropical marine environment. Some were required to have uplift capacity, all were to be resistant to salt build-up, and all were required to be virtually maintenance free for a 25 year life. Whilst the majority of the bearing components ('pot' cylinders and pistons) were made from 316 and 316L stainless steel, the large-movement slide plates were made from grade 2205 duplex stainless steel, with a facing of polished Inconel 625, fully TIG welded around its perimeter. Thermal coefficients of expansion of mating parts were matched. Assembled bearings were tested in overload and friction, both at ambient temperature at 140°C.

The bearings were fabricated at the firm's Castle Hill, Sydney factory and transported to Batam, Indonesia where they were incorporated into the structure for the final trip to site.

The bearings measure up to 2m long and weigh up to 3 tonne each with attachments plates. They were also designed to withstand severe impact during installation.

The various bridges, platforms and piping are currently bring assembled.

For more information on Bayu Undan, visit www.offshore-technology.com/projects/bayu-undan

This article featured in Australian Stainless magazine - Issue 23, December 2002.

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Walsh Bay

A Style Statement in Stainless


Posted 1 December 2002

The transformation of Sydney's Walsh Bay from derelict wharves and sheds into a prestigious residential complex, complete with cultural, retail and commercial facilities, provides a stage for Australian innovation in design and technology, including some of the finest examples of stainless steel structural and architectural applications.

Located amid Sydney's landmarks -the Opera House, Circular Quay, The Rocks and Sydney Harbour Bridge -the Walsh Bay Precinct is said to be "the most significant urban renewal of heritage Sydney to be undertaken for many years."

According to developers Walsh Bay Partnership (WBP), a joint venture project between Mirvac and Transfield, "the redevelopment captures an exceptional balance between Walsh Bay's rich heritage, sympathetic contemporary design, and the vision to revitalise Walsh Bay as Australia's finest new residential address."

The development features 350 luxury apartments, 140 of them located on Pier 6f7, one of the five "finger wharves" constructed between 1906 and 1922 to serve Sydney's expanding commercial shipping activity. But the area's history goes back much further: Walsh Bay was one of Sydney's first industrial ports, dating back to 1820. Like many other city ports around the world, Walsh Bay ceased operations in the '70s and by the late '90s much of the area was unused and neglected.


New Technology Preserves Authentic Feel
WBP was formed in '97 to undertake restoration, with an emphasis on conservation strategies such as salvaging the old hardwood timbers and historical artefacts. Over 80% of the original buildings are being retained and the style of new construction is required to evoke and interpret Walsh Bay's rich heritage. Preserving its historic appeal, unique operable louvres which mimic the original timber planks face the 200m long refurbished pier. These are made from aluminium and supported by grade 316 stainless steel brackets. The louvres pivot on stainless steel supports, allowing them to withstand winds up to 130krnlh. As a safety measure, they close automatically if the weather worsens. They were designed by Architectural Glass Projects Pty Ltd, a Sydney firm which specialises in building components such as glass facades, operable louvres, balustrading and specialised glazing.

 

Stainless to Resist Sea Spray
To take best advantage of its Sydney Harbour location, a marina with private boat moorings accessible from ground-level apartments runs along both sides of the pier and features     stainless steel steps, gates and balustrades.

Starting with the right materials and selecting the most appropriate surface finish are key factors for ensuring the quality and life-cycle of the finished project, particularly in harsh marine environments. A surface roughness (Ra) under O.SJ.Jm using 320 grit abrasives was specified for the stainless steel used in this project. Mechanical grinding was followed by electropolishing, a chemical process which smooths and levels the surface, to produce the best protection against tea staining and contamination.

Surface treatments were carried out by two ASSDA members, MME Surface Finishing and Metaglo Pty Ltd. A large proportion of the stainless steel material used was imported large extruded T and 'L' sections up to 150mm deep. MME, which has the capacity to process elements up to 6.5m long by either mechanical means or electropolishing, modified machines and developed new techniques to produce a consistent O.SJ.Jm finish throughout. Components were returned to MME after fabrication for immersion pickling and electropolishing.

An Asset for Sydney
The revitalised Walsh Bay precinct is set to become an attraction for residents and visitors when it opens next year. As well as offices and apartments, the development includes a new cultural centre, an 850 seat theatre, parks, restored bridges and walkways. A promenade will link Walsh Bay to The Rocks and Circular Quay, opening up the foreshore to the public for the first time in over a century.

This article featured in Australian Stainless magazine - Issue 23, December 2002.

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Walking on Water


Posted 1 September 2002

Pedestrians using Brisbane’s scenic RiverWalk when it opens next March will be strolling across 150 tonnes of stainless steel reinforcing, embedded in 287 concrete pontoons linked to form an 875 metre long walkway from the CBD along the river to New Farm Park.

Although the 5.4 metre wide walkway will feel like a single solid structure, it is actually made up of a series of 13.5 tonne concrete blocks, half of their bulk floating below the water level.

Stainless steel balustrades will preserve open views across to Southbank and back to the CBD while ensuring public safety. These combine subtly curved 600 grit electropolished handrails which give a wave effect and 320 grit polished end-posts and staunchions with an art deco feel.

An overall Ra of 0.5 mm was specified not just for the aesthetics but to provide maximum corrosion resistance for grade 316 stainless in a marine environment and to minimise tea-staining.

Stainless steel wire strung horizontally between the posts will provide a strong safety barrier while fading to invisibility from just a few metres away. Customised tamper-proof electropolished turnbuckles developed by ASSDA member Ronstan International Pty Ltd and the posts inward-curving profile will ensure that RiverWalk meets stringent safety standards.

Night-time illumination will come from Y-shaped light poles placed at 30 metre intervals and spot lighting will highlight decorative elements such as mosaics.

Each section of the balustrade runs the length of an individual pontoon. Sections are joined with a tapered stainless steel sleeve to absorb the small amount of movement from wave action, expected be around 20mm.

AN INNOVATIVE BASE FOR A SCENIC WALKWAY
Assembly of the concrete pontoons involves advanced construction methods modelled on the latest overseas developments and a similar, but much smaller, floating walkway which was successfully built on Melbourne’s Yarra River.

To obtain the necessary strength and buoyancy, high strength 50mPa concrete is reinforced with grade 316 stainless steel. The 10mm and 12mm diameter rebar is fashioned into a cage around a polystyrene core which takes up 85% of the pontoon’s volume. The corrosion-resistant properties of stainless steel reinforcing enable the pontoon to be built with narrower walls than would be the case with conventional reinforcing creating savings in the amount of concrete required.

With stainless steel reinforcing an impressive lifespan is assured, making it the best long-term option in building assets where longevity is desired. The design life of this structure is 100 years.

Funded by the Brisbane City Council (BCC) and developed by a BCC and consultant design team led by project architect Jan Jensen, RiverWalk is one of the city’s most ambitious and forward looking projects. It uses techniques which are new to Australia and draws on the expertise of many construction professionals including stainless steel materials experts, suppliers and fabricators.

ASSDA’s role in the project included detailed specification advice on all aspects of the stainless steel work and provision of detailed answers to technical issues in design and prototyping.

Construction contractor Smithbridge Australia Pty Ltd heads the project team which also includes a number of ASSDA members, including Pryde Fabrication, Arminox Australia Pty Ltd and Stoddart Metal Fabricators.

This article featured in Australian Stainless magazine - Issue 22, September 2002.

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Stainless Strength for Bridge Projects


Posted 28 February 2002

The Tasmanian Government has embarked on a series of bridge renewal projects, using stainless steel reinforced pre-cast concrete to replace old timber structures.

The Barnes Creek bridge is the first of three to be rebuilt on Brunie Island, south of Hobart. It utilised 7.5 tonnes of grade 316 and duplex 2205 stainless reinforcing bar in a size range of 12 to 25mm supplied by ASSDA member Arminox Australia Pty Ltd.

The Tasmanian Department of Infrastructure, Energy and Resources specified stainless steel for the reinforcing to save on ongoing maintenance costs. The location of the bridge presents construction and maintenance challenges, with the site only accessible by ferry.

The grade was selected to meet the demands of an aggressive marine environment. The bridge is subject to salt-laden winds and salt water covers the foundations at high tide. The 6.5m bridge, which connects local rural and residential areas, has a service life expectancy in excess of 100 years.

SORELL CAUSEWAY
Another of the Department's major projects is the construction of a new 490m bridge connecting the Tasmanian east coast to the Tasman Peninsula. The new Sorell Causeway has been designed to cater for heavy vehicles, a high volume of local traffic and tourists travelling from Hobart to Port Arthur. A small quantity of only 6.5 tonnes of stainless steel 316 and duplex 2205 reinforcing is being used in the critical area of the pile cappings.

This article featured in Australian Stainless magazine - Issue 20, February 2002.

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Style + Strength


Posted 28 February 2002

The superior strength of stainless steel has long made it the material of choice for prison toilet facilities. Innovative styling has now opened up a new market in public restrooms. Increasingly, venues are turning to stainless steel to make their facilities safer and reduce costs in the long term.

Vandalism in public facilities is a widespread occurrence, with some pub and club owners forced to replace a toilet every few weeks. While the initial outlay may be higher for stainless fittings, the cost of replacing and installing a ceramic pan can be recouped after just one instance of vandalism. Unbreakable stainless steel also eliminates the risk of injury from sharp ceramic shards and the inconvenience of effluent overflow.

Stylish designs mean that aesthetics aren't sacrificed for practicality. Martin O’Brien, General Manager of the recently refurbished QA Hotel in Brisbane’s Teneriffe, says stainless steel was the logical choice because it’s "tough as teeth, durable and looks good. Stainless steel was the best way to go - its clean lines never go out of date." As part of a total makeover, the QA replaced ceramic tiles and fittings with stainless steel. O’Brien says vandalism in pubs is a big issue, with "punters" taking out their frustrations in the bathrooms and causing a lot of damage to conventional fittings.

ELEGANT AND FUNCTIONAL
Metal, timber and black are the predominant themes in the $3 million refurbishment of the 120-year-old Regatta Hotel, overlooking the Brisbane River. Conceived by owner-developer Steve Hammond, the renovation juxtaposes high tech and rustic, with gleaming metal and glass surfaces set against timber frames and sandblasted brick walls. The metallic theme continues outside with stainless steel topped café tables on the pavement and verandahs, and aluminium louvres replacing traditional lattice.

Stainless steel is integral to the washroom design, combining clean, minimalist lines with durability, vandal-resistance and minimum maintenance. Push pad controls replace vulnerable taps, while moulded stainless steel pans with in-wall slimline cisterns and push pad flush eliminate other targets for vandals. Stainless steel is used for mirrors, air-towels, soap and toilet paper dispensers.

Stainless steel fabricator Stoddart, who drew on the resources of ASSDA to develop a commercial product range, says their pans are often specified as part of a suite to fit in with a high-tech, architectural look. This project used Stoddart's standard shrouded toilet made from satin finished, 316 stainless to withstand heavy duty cleaning products. A pin inside the bowl prevents objects like wine glasses being flushed into the plumbing. The flat plate design of the rim flush makes the toilet contraband-proof and the unit has the advantage of being able to be fixed onto a wall from the inside.

Stainless steel features heavily elsewhere in the bar frames and counters and in a microbrewery. Three 2 000 litre stainless steel tanks with decorative copper cladding have been incorporated into the design of the downstairs bar. The beer is piped to fermentation tanks in the upstairs bar, which form a backdrop to the dancefloor. Apart from providing a theming enhancement to a predominantly beer pub, the installation of a microbrewery was a commercial decision in response to a growing demand for boutique and specialty beers, says project manager Rob Forbes.

BEACHFRONTS AND PARKS
Local authorities present another significant market for stainless steel amenities. Gold Coast City Council, which for some years has had a policy of replacing vandalised ceramic toilets with stainless steel ones, is now installing stainless steel pans in all new public convenience blocks. To improve safety, the Council is also considering installing stainless steel woven security mesh near the entrance of public toilets. The one-way screen allows people to see if is there is a threat outside the building before exiting.

STYLISH STAINLESS SHOWERS
In conjunction with Stoddart, Gold Coast City Council is developing a prototype stainless steel shower to eliminate the corrosion problems of beachside installation. Ian Munro, Supervisor in the Council’s Building & Maintenance section, says the project has attracted interest from other councils on the coast. Seven showers are currently being tested. ASSDA member Stoddart has also manufactured stainless steel street furniture for Casuarina Beach on the Tweed Coast in northern NSW including beach-themed showers in 316 stainless. These are designed to be vandal and weather resistant and feature automatic water cut-off to prevent wastage.

Image on left: Casuarina Beach 316 stainless surfboard shower. Design by Hutton-Harris. Fabrication by Stoddart.

This article featured in Australian Stainless magazine - Issue 20, February 2002.

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Council Impresses With Stainless


Posted 28 February 2000

When the Gold Coast City Council was seeking a stable and visually stunning medium for use on their Kirra Point board walk project, they looked no further than stainless steel!

Geoff Clemence, Design Coordinator, said Council engineers chose stainless steel for the upright posts and moveable hand rail system for safety, corrosion resistance and aesthetic reasons.

"Stainless is far superior to wooden handrails in terms of safety and lasting life and will require far less maintenance," Mr Clemence said.

"From an aesthetic point of view, the stainless steel fits in beautifully with both the concrete pavement and the timber board walk that we will be installing in the near future," Mr Clemence said.

"Once the board walk is built, there will be a vertical drop to the beach below - an important safety issue met by using stainless steel handrailing.

"We had to choose what the best solution would be to the issue of safety that the steep drop off on the side of the walkway would cause," Mr Clemence said.

"Stainless steel was the safest option."

The board walk project is being undertaken in two stages, the first of which involved constructing a cement walkway and handrails along the Kirra Point foreshore.

The second stage will see the construction of a timber board walk out over the foreshore onto the beach.

ASSDA Sustaining Members Tom Stoddart Pty Ltd supplied 186 custom made upright posts and supplied and installed 326 metres of stainless steel tubular handrails.

Both were made from 316 grade stainless steel with a number 4 finish.

The upright posts were passivated in nitric acid after manufacture to ensure a clean surface and promote corrosion resistance.

During the installation, the welds in the posts were fully grounded and polished on site to stop sand and salt deposit build-up.

The hand railing is made up of 6 metre segments of tubular stainless steel welded on site.

Expansion joints are included every 7.2 metres.

The expansion joint allows for thermal movement and the inclusion of additional railings when a timber board walk is built in 2001.

The Gold Coast City Council engineers acknowledged the assistance provided by the Australian Stainless Steel Development Association in highlighting the possibilities and advantages of stainless applications, in meetings leading up to specification in the project.

This article featured in Australian Stainless magazine - Issue 15, February 2000.

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Duplex 2205 used for United Nations Navy Recompression Chambers


Posted 17 May 1999

When the United States Navy required 35 lightweight transportable recompression chambers in the late 1980s, Cowan Manufacturing took up the challenge of developing the units.

Cowan Manufacturing developed a prototype out of a virtually unknown material. It was duplex 2205 (UNS 31803) stainless steel.

No other manufacturer in the world was producing chambers out of 2205 and, after six years of negotiations, Cowan was sourced as the sole supplier of the chambers.

Cowan chose 2205 for its high strength, light weight and corrosion resistant properties. This enabled them to meet the Navy's requirements without the weight and corrosion problems of other materials.

Traditionally, recompression chambers have been made out of carbon steel and required high maintenance because of the severe marine environment in which they are used (on ships at sea). Chamber walls had to be thick to combat the effects of corrosion and so were very heavy.

The strength and corrosion resistance of 2205 over other materials enabled the chamber shell thickness to be reduced to 3mm. The thinner chamber walls effectively halved the weight of the units and corrosion resistance lengthened their service life.

However, Cowan faced some difficulties with the material because it was new on the market at the time. Staff had to be specially trained in welding techniques for the 2205 which had to be approved by Navy certification teams. (2205 is now a common material that is used for many industrial applications.)

The 2205 material was supplied by Sandvik Australia. The 3mm x 2000mm wide coil material was sized on its cut to length line and plasma arc cut the conical sections and the end cap discs which were then formed by Dome Engineering.

The strict quality requirements specified by the US Navy resulted in all material being ultrasonically examined and charpy tested before processing.

The chambers were produced at the Cowan Manufacturing facility at Warners Bay in New South Wales. Cowan has since become a specialist
in its field, supplying recompression chambers to 12 countries including the United States and Australia.

This article featured in Australian Stainless magazine - Issue 13, May 1999.

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Grade 316 - the 'first step up'


Posted 17 May 1999

If a job requires greater corrosion resistance than grade 304 can provide, grade 316 is the 'next step up'. Grade 316 has virtually the same mechanical, physical and fabrication characteristics as 304 with better corrosion resistance, particularly to pitting corrosion in chloride environments.

Grade 316 (U NS S31600) is the second most popular grade accounting for about 20% of all stainless steel produced.

This article follows on from "304 -the place to start" in Issue 10 which is also available on ASSDA's website at www.assda.asn.au

COMPOSITION
Table 1 compares three related grades - 316, 316L and 31 6H.

Grade 316L is a low carbon 316 often used to avoid possible sensitisation corrosion in welded components.

Grade 316H has a higher carbon content than 316L, which increases the strength (particularly at temperatures above about 500°C), but should not be used for applications where sensitisation corrosion could be expected.

Both 316L and 316H are available in plate and pipe, but 316H is less readily available ex-stock. 316L and 316H are sometimes stocked as standard 316 (test certificates will confirm compliance with the 'L' or 'H' specification).

CORROSION RESISTANCE
Grade 316 has excellent corrosion resistance in a wide range of media. Its main advantage over grade 304 is its increased ability to resist pitting and crevice corrosion in warm chloride environments. It resists common rusting in virtually all architectural applications, and is often chosen for more aggressive environments such as seafront buildings and fittings on wharves and piers. It is also resistant to most food processing environments, can be readily cleaned, and resists organic chemicals, dye stuffs and a wide variety of inorganic chemicals.

In hot chloride environments, grade 316 is subject to pitting and crevice corrosion and to stress corrosion cracking when subjected to tensile stresses beyond about 50°C. In these severe environments duplex grades such as 2205 (UNS S31803) or higher alloy austenitic grades including 6% molybdenum (UNS S31254) grades are more appropriate choices.

The corrosion resistances of the high and low carbon versions of 316 (316L and 316H) are the same as standard 316.

HEAT RESISTANCE
Like grade 304, 316 has good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of 316 in the 425-860°C range is not recommended if subsequent exposure to room temperature aqueous environments is anticipated, but it often performs well in temperatures fluctuating above and below this range.

Grade 316L is more resistant to carbide precipitation than standard 316 and 316H and can be used in the above temperature range. However, where high temperature strength is important, higher carbon values are required. For example, AS 1210 Pressure Vessels Code limits the
operating temperature of 316L to 450°C and restricts the use of 316 to carbon values of 0.04% or higher for temperatures above 550°C. 316H or the titanium-containing version 316Ti can be specified for higher temperature applications.

316 has excellent toughness down to temperatures of liquefied gases and has application at these temperatures, although lower cost grades such as 304 are more usually selected for cryogenic vessels.

PHYSICAL AND MECHANICAL PROPERTIES (see Tables 2 and 3)
Like other austenitic grades, 316 in the annealed condition is virtually nonmagnetic (ie. very low magnetic permeability). While 304 can become significantly attracted to a magnet after being cold worked, grade 316 is almost always virtually totally non-responsive. This may be a reason for selecting grade 316 in some applications.

Annealing (also referred to as solution treating) is the main heat treatment carried out on grade 316. This is done by heating to 1,010-1,120°C and rapidly cooling - usually by water quenching.

FABRICABILITY
316 can be deep drawn without intermediate heat softening enabling it to be used in the manufacture of drawn stainless parts, such as sinks and saucepans. However, for normal domestic articles the extra corrosion resistance of grade 316 is not necessary. 316 is readily brake or roll formed into a variety of other parts for application in the industrial and architectural fields.

Grade 316 has outstanding weldability and all standards welding techniques can be used. Although post-weld annealing is often not required to restore 316's corrosion resistance (making it suitable for heavy gauge fabrication) appropriate post-weld clean-up is recommended.

Machinability of 316 is lower than most carbon steels. The standard austenitic grades like 316 can be readily machined if slower speeds and heavy feeds are used, tools are rigid and sharp, and cutting fluids are involved. An 'improved machinability' version of 316 also exists.

COST COMPARISONS
The guidelines in Table 4 are approximate 'first cost' comparisons for sheet material in a standard mill finish suitable for construction projects. The appeal of stainless over its first cost competitors dramatically increases
when lifecycle costs are considered.

FORMS AVAILABLE
Grade 31 6 is available in virtually all stainless product forms including coil, sheet, plate, strip, tube, pipe, fittings, bars, angles, wire, fasteners and castings. 316L is also widely available, particularly in heavier products such as plate, pipe and bar. Most stainless steel surface finishes, from standard to special finishes, are available.

APPLICATIONS
Typical applications for 316 include boat fittings and structural members; architectural components particularly in marine, polluted or industrial
environments; food and beverage processing equipment; hot water systems; and plant for chemical, petrochemical, mineral processing, photographic and other industries.

Although 316 is often described as the 'marine grade', it is also seen as the first step up from the basic 304 grade.

Alternative grades to 316 should be considered in certain environments and applications including:

• strong reducing acids (alternatives might be 904L, 2205 or a super duplex grade),
• environments with temperatures above 50-60°C and with chlorides present (choose grades resistant to stress corrosion cracking and higher pitting resistance such as 2205 or a super duplex or super austenitic), and
• applications requiring heavy section welding (316L), substantial machining (an improved machinability version of 316), high strength or hardness (perhaps a martensitic or precipitation hardening grade).

 

This technical article featured in Australian Stainless magazine - Issue 13, May 1999.

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Stainless Strengthens Walls


Posted 17 May 1999

The devastation of the 1989 Newcastle earthquake resulted in a revision of standards specifying building materials and products to be used in differing environments.

One of the products that came under close scrutiny was wall ties (also known as brick ties).

Assessment of the damage after the earthquake found that many walls had 'peeled away' from building structures due to deteriorated wall ties.

A wall tie connects masonry to the structural backing which supports the wall. The most common wall ties are manufactured out of galvanised steel.

Australian Standard AS 3700 - 1998 revised the conditions under which wall ties are used and made recommendations about the types of material that should be used in different environments.

The Standard specifies that 316 or 316L stainless steel wall ties should be used in 'R4' category environments. These are severe marine environments, usually up to 1 00 metres from a nonsurf coast or one kilometre from a surf coast, where the highest airborne salinity level at the exterior of the masonry is 300 g/m2/day.

In such environments the chlorides in the air make it highly corrosive and not suitable for wall ties manufactured from materials that are susceptible to corrosion.

However this requirement is the subject of debate, with some specialists suggesting that corrosive environments stretch well beyond the distances specified in the Standard.

The use of stainless steel wall ties as suggested in the Standard will increase the safety and durability of buildings in corrosive environments for a very small increase in the overall cost. This again leads to the debate about what constitutes a corrosive environment, and whether the Standard should be more conservative.

The revised Standard has been incorporated into the Building Code of Australia and is mandatory for many provisions in the Code. The Australian Building Codes Board anticipates AS3700 - 1998 will become mandatory for the Housing Provisions in January 2000.

Thus, opportunities exist for the stainless industry to be proactive in its approach to such issues, as well as to investigate the use of stainless in other building applications, where durability and strength are principal concerns.

This article featured in Australian Stainless magazine - Issue 13, May 1999.

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