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A Stainless Facelift for Surfers Paradise

Stainless is a key feature in the urban design and revamp of one of the Gold Coast's most iconic and vibrant tourist destinations.

The $25 million Surfers Foreshore Project was commissioned by the Gold Coast City Council (GCCC) to redevelop the beachfront area between Laycock Street and View Avenue in Surfers Paradise.

Aimed at improving infrastructure and visitor recreation, the new promenade features new lifeguard towers, amenity blocks, beach shelters, picnic areas with barbeques, and increased pedestrian and disability access to the beach.

Managing Contractor Abigroup Contractors Pty Ltd appointed ASSDA member and Accredited Fabricator J&T Mechanical Installation to fabricate and install the stainless steel architectural handrails and balustrades across stages 1, 2 and 3.

Trent Todd, J&T Mechanical Installation’s Director, said that with the handrails and balustrades being installed less than 30m from the shoreline, stainless steel was the only choice to withstand the harsh coastal environment to help resist tea staining and ensure long-term durability and performance.

A 2009 GCCC study in affiliation with Griffith University saw the GCCC adopt stainless steel as the default specification for structures with a design life of more than 19 years in foreshore zones.

This followed research results showing the material required lower maintenance and was the most effective in life cycle costs when compared with hot dipped galvanized (HDG) steel, paint systems and duplex systems using both HDG and paint.

At a total cost of approximately $80,000, the stainless steel handrails and balustrades span 1300m across the esplanade that fronts Surfers Paradise Beach.

Grade 316L stainless steel was specified for these elements of the project, which included 36 sheets of 10mm thick plate measuring 1500mm x 3000mm supplied by ASSDA member Allplates. ASSDA Sponsor STM Tube Mills Pty Ltd supplied 1300m of 50.8mm x 1.6mm thick tube. Another 3500m of 1/4” wire was also sourced for the balustrading.

All the flat and tube components including 124 stanchions were laser cut and folded by Allplates.

Stanchions and base plates were machine polished to 600 grit by ASSDA member and Accredited Fabricator Minnis & Samson to give the stainless steel an even polish and the stanchions a square edge. The stanchions were electropolished before being delivered back to J&T Mechanical Installation’s workshop for assembly.

J&T Mechanical Installation fabricated the top (50.8mm x 1.6mm tube) and bottom (folded channel, 4mm thick) rail frames with two vertical 16mm diameter solid round bar intermediate supports. Infill wires at 6.4mm diameter were positioned with swage fittings and lock nuts on each end to construct the vertical balustrades.

On site, J&T Mechanical Installation completed civil works prior to installation, including pre-drilling with the fasteners for the base plates to which the stanchions were then bolted. The rail frames were welded to the stanchions in 2.1m sections.

Following installation, a proprietary stainless steel cleaner was applied to remove any oxides, and a mild cleaner was followed to provide surface protection and inhibit corrosion.

Architectural feature lighting was installed to illuminate the pedestrian walkways at night.

The Surfers Foreshore Project was completed in April 2011 and today continues to thrive as the Gold Coast’s most popular entertainment precinct where city meets the surf.

Images courtesy of Allplates.

This article is featured in Australian Stainless magazine, issue 51.

Guidelines for Use of Stainless Steel in the Ground

Stainless steel can provide excellent service underground. It is stronger than polymers and copper and its resistance to chlorides and acidic acids is significantly better than carbon or galvanised steels.

The performance of stainless steel buried in soil depends on the nature of the buried environment. If the soil has a high resistivity and is well drained, performance can be excellent even in conditions where other unprotected materials suffer degradation.

BASIC RULES

The Nickel Institute guidelines for burial of bare stainless steel in soil require:

  • No stray currents (see below) or anaerobic bacteria
  • pH greater than 4.5
  • Resistivity greater than 2000 ohm.cm.

Additional recommendations include the absence of oxidising manganese or iron ions, avoidance of carbon-containing materials and ensuring a uniform, well drained fill. If the guidelines are breached, then either a higher resistivity is required, i.e. measures to lower moisture or salts and ensure resistivity exceeds 10,000 ohm.cm, or else additional protective measures may be required.
In comparison, the piling specification (AS 2159) guidelines for mild steel require a pH greater than 5 and resistivity greater than 5000 ohm.cm for soils to be non-aggressive. It is rare for bare mild steel to be buried, i.e. typical specifications include a wrap or coating possibly with a cathodic protection system.

SPECIFIC ISSUES

  • Uniform soil packing is required as variable compaction can induce differential aeration effects.
  • Avoid organic materials in the fill around buried stainless steel as they can encourage microbial attack.
  • Avoid carbon-containing ash in contact with metals in soils. Localised galvanic attack of the metal can occur.
  • Oxygen access is critical. Having good drainage and sand backfill provides this. A sand-filled trench dug through clay may become a drain and it is not appropriate. Stainless steels generally retain their passive film provided there is at least a few ppb of oxygen, i.e. 1000 times less than the concentration in water exposed to air.
  • Chlorides are the most frequent cause of problems with stainless steels. In soils, the level of chlorides vary with location, depth and, in areas with rising salinity, with time.  High surface chlorides may also occur with evaporation. This is a problem for all metals although stainless steels are not usually subject to structural failure.

The general guidelines for immersed service are that in neutral environments at ambient temperatures and without crevices, 304/304L may be used up to chloride levels of 200ppm, 316/316L up to about 1000ppm chloride and duplex (2205) up to 3600ppm chloride. The super duplex alloys (PRE>40) and the 6% molybdenum super austenitic stainless steels are resistant to seawater levels of chloride, i.e. approximately 20,000ppm. These guidelines are easy to apply in aqueous solutions.

Soil tests for chlorides may not exactly match actual exposure conditions in the soil. Actual conditions may be more (or less) severe than shown by the tests. The difference is calculable but in practice, the aqueous limits can be used as general guidelines. More specific recommendations, based on published guidelines, are provided in Table 1.

 

 

It may seem redundant to assess both chlorides and resistivity. Both are required as the resistivity is primarily affected by water content and if it is low, then quite high chlorides could be tolerated – as seen by the choice of 304/304L in high chloride/high resistivity conditions.  Despite these recommendations, most Australian practice is to use 316/316L or equivalent, primarily because of variable soils.

  • Good drainage and uniform, clean backfill are essential for bare stainless.
  • Duplex or super duplex could be replaced with appropriate austenitics and 304/304L could be replaced with a lean duplex.
  • Ferritic stainless steels of similar corrosion resistance (usually classified by Pitting Resistance Equivalent [PRE]) could also be used underground.

Potential acid sulphate soils are widespread, particularly in coastal marine areas as described in http://www.derm.qld.gov.au/land/ass/index.html. Once disturbed and drained, which also allows oxygen access, such soils typically become more acidic than pH 4 and will attack metals (although stainless steels will be less readily attacked than other metals). Detailed assessment is required if using metals in such an environment as the effect of other aggressive ions is likely to be more severe at low pH.

  1. Properly specified stainless steel can provide the longest service underground. It is strong compared to plastics and copper, and is more reliably corrosion resistant than carbon steel.
  2. Table 1 guides grade choice for soil conditions.
  3. Normal fabrication practices apply: welds must be pickled and carbon steel contamination avoided.
  4. Pipelines must be buried in clean sand or fine, uniform fill in a self-draining trench that avoids stagnant water. Organic or carbonaceous fill must be avoided.

CASE STUDIES

The Nickel Institute published a five year Japanese study in 1988 (#12005) showing 304 and 316 gave good service in buried soil, although vertically buried pipes did suffer some minor pitting and staining apparently due to differential aeration effects.

  • NI #12005 describes a five year burial exposure in Japan at 25 sites with highly varied corrosivity. After five years in marine sites, horizontal 304 pipes showed no pitting but some crevice attack under vinyl wrap. Only one 316 pipe showed any attack.
  • Vertical 304 pipe suffered attack near the base at some sites apparently due to differential aeration effects.
  • An Idaho study of a 33-year NIST burial found 12% Cr martensitics perforated. The ‘lake sand’ site had high ground water with pH 4.7 at recovery. Sensitised 304 was attacked worse than annealed but both suffered attack along the rolling direction from edges.
  • 316 was not attacked even if sensitised.

As noted, duplex stainless steel of similar corrosion resistance (PRE) to 304 and 316, respectively, would be expected to provide similar results when buried.

On a more practical level, there are several common approaches that are used when burying stainless steel:

  • Wrap the stainless steel pipe in a protective material, such as a petrolatum tape, prior to burial. If the wrapping is effective (typically an overlap no less than 55% of the wrap width is specified), then the nature of the external surface of the buried pipe is of no consequence. In this case, stainless steel is only used for its internal corrosion resistance, i.e. its resistance to corrosion by the fluid which the pipe is carrying. Some authorities prohibit this practice because of concerns that damage to the wrap could cause a perforating pit in severe environments.
  • Ensure that the soil environment surrounding the buried stainless steel is suitable for this application. In this case, the trench is dug so that it is self-draining, without there being areas where stagnant water can accumulate in contact with the buried pipe. The stainless steel pipe is then placed on a sand or crushed aggregate bed and covered by similar material. Under these circumstances,  316 grade stainless steel can be quite a suitable choice. US practice is to use 304 but Australian soils are quite variable and there have been mixed experiences with 304.
  • Above ground sections of pipework are often stainless steel as they are at risk of mechanical damage while underground pipework is polymeric - polyethylene (PE) or fibre reinforced plastic (FRP) - despite the risk of damage due to soil movement.

In all of these cases, the assumption is that the stainless steel has been fabricated to best practice. This includes pickling of welds (or mechanical removal of heat tint and chromium depleted layer followed by passivation to dissolve sulphides) and ensuring that contamination by carbon steel has been prevented. It is also assumed that the buried stainless steel does not have stickers or heavy markings that could cause crevices and lead to attack.

STRAY CURRENTS

All buried metals, including stainless steels, are at risk if there are stray currents from electrically driven transport, incorrectly installed or operated cathodic protection systems, or earthing faults in switchboards. Stray current corrosion can be identified as it causes localised general loss rather than pitting. It is also very rapid.

WHAT TEST METHODS ARE USED?

There are Australian and ASTM standards giving basic measurements of resistivity on site with 4 pin Wenner probes or in a soil box in the laboratory. More detailed checking includes water content, chlorides, organic carbon or Biological Oxygen Demand (BOD), pH and redox (or Oxidation Reduction Potential [ORP]) potential – which assess microbial attack risk but also captures the effect of oxidising ions and dissolved oxygen. Most of these test methods are covered in “Soil Chemical Methods: Australasia” written by George E Rayment and David J Lyons and published by CSIRO.

 

SOIL

Natural soils are a mixture of coarse pebbles, sand of increasing fineness through to silts and clays where the particles are less than 5 µm in diameter.  Some of the particles contain soluble salts that, if mixed with water, are likely to be corrosive. Normally, soils also contain organic material from decaying plants or ash, which can provide nutrients for microbial activity or galvanic effects, respectively.

If water is present in the soil, corrosion can take place. Metals below the water table can corrode (following the rules for immersed service). However if the soil is well compacted so oxygen cannot gain access or corrosion products cannot diffuse away, then corrosion would be stifled - even for carbon steel. Above the water table, moisture comes from percolating rain, which will, over time, leach away soluble corrosives and make the soil less aggressive. This also means that in dry climates, salts may accumulate and when there is rain, the run-off or percolating water is very aggressive.  Deposited salts can also be a problem in marine zones almost regardless of rainfall.

Most of the moisture above the water table is bound to particles but if there is sufficient water content, typically more than about 20%, enough water is free to wet buried metals.

Image pictured is the Appin Sewerage Treatment Plant, NSW. Fabricated and installed by ASSDA member and Accredited Fabricator Roladuct Spiral Tubing Pty Ltd using 316 grade stainless steel. Image courtesy of Roladuct Spiral Tubing Pty Ltd.

This technical article is featured in Australian Stainless magazine, issue 51.

Stainless = Freshness

As bottled water continues to gain popularity in Australia, maintaining the quality and purity of the water extracted from natural springs is paramount.

This is just one example within the food and beverage sector where hygiene is vitally important and, therefore, stainless steel continues to be the material of choice for processing and storage facilities.

In 2011, Coca-Cola Amatil (CCA) commissioned ‘Project Flint’ to upgrade three spring water storage tanks for their Moorabbin plant in Victoria plus an additional two tanks for their Thebarton plant in South Australia.

GEA Process Engineering Australia engaged Byford Equipment on behalf of CCA to fabricate and install the five storage tanks.

GEA Engineering’s General Manager Operations, Andrew Fillery, said stainless steel was an important specification as the tanks had to cope with the chemical and thermal rigours of cleaning processes.

“Stainless steel was chosen for process and hygienic reasons, and the vessels needed to withstand the process and cleaning conditions where mild caustic and acid CIP solutions were used,” said Fillery.

Strength and durability was key for the 200,000L capacity silos, which measured 4.7m in diameter by 14.5m high for the Moorabbin site and 5.5m in diameter by 10m high for the Thebarton plant.

ASSDA Sponsor Midway Metals supplied 27 tonnes of grade 304 stainless steel coil with a 2B finish in 2mm, 2.5mm, 3mm and 4mm thicknesses. The coil widths were 1219mm and 1500mm.

With a team of five fabricators on the project, the tanks were welded together using a semi-automatic MIG welding process. The welds were then pickled to restore the chromium oxide layer and abstain from rusting.

Byford Equipment’s Project Manager Geoff Smallwood said coordinating the delivery of the tanks was a challenge, given the logistics of travelling through three states by road.

The delivery of the vessels was critical added Fillery, as there were specific installation windows to work within.

The storage tanks were delivered from Byford’s workshop in New South Wales to Moorabbin in March 2011. The two remaining tanks were delivered to Thebarton a month later for installation. It took one day and one crane to install each tank on site.

The connecting pipework was positioned on site, which was grade 304 polished tube in diameters ranging from 38mm to 150mm and purge welded prior to installation.

Images courtesy of Byford Equipment.

This article is featured in Australian Stainless magazine, issue 51.

Chimpanzee Sanctuary

Where Strength Meets Style

Innovation in zoo enclosure design is a key feature of the recently completed $7.5 million makeover of the Chimpanzee Sanctuary at Sydney’s Taronga Zoo.

The project brief was to create a chimpanzee habitat akin to their native home that would encourage social interaction and allow the zoo’s primate keepers to manage animal husbandry and the group’s changing demographic. The enclosure’s transparency and the ability to withstand the chimpanzee’s remarkable strength and intelligence were essential.

ASSDA member Ronstan Tensile Architecture was contracted by the builder, the Lipman Group, to be the specialist contractor for the technical design and installation of a mesh enclosure and non-climbable wall. Ronstan’s unique capability in tensile architecture and their technical expertise were a natural fit for this challenging project designed by Jackson Teece Architects.

The Sanctuary features the mesh separation paddock (similar to an aviary), at one end of the main exhibit. A non-climbable wall with a removable curtain, allows both spaces to function as one large paddock. This enables introductions of new chimpanzees into the compound and helps manage the apes’ complex behaviour patterns.

Ronstan Tensile Architecture’s General Manager, Rowan Murray, said the non-climbable wall structure was one of the most the challenging design aspects.

“The architect’s greatest challenge was to separate the chimpanzees physically, but still have them all in view in the paddock. We had to build a wall that was transparent, had openings of no more than 5mm to avoid chimpanzees putting their fingers in and climbing, and could withstand the strength of chimpanzees.” Mr Murray said.

The structural complexity of the non-climbable wall required 3D modelling to analyse design configurations and ensure structural integrity. Test panels of the non-climbable wall were fabricated and assessed in the chimpanzees’ temporary enclosure to determine which would offer the safest containment of the site and minimise visibility.

Mr Murray said the primary structure for the wall consists of a Ronstan supplied tensile cable net that supports semi-transparent perforated stainless steel panels.

“Most materials can be damaged, but the durability of stainless steel panels of certain perforation proved to be the right solution and important in the development of the overall design,” he said.

“The non-climbable wall had been designed with wall panels clamped directly to the enclosure mesh face. In a collaborative effort, we changed this to an independent cable net structure to remove the risk of having the final wall shape differ from that modelled, and in doing so, avoided the risk of panel geometry differing from the complex 10 degree incline necessary for non-climbability. This also ensured uniform set out and fixing methods, more consistent panel shapes and allowed the panel geometry to drive the wall structure rather than this being determined by other elements.”

ASSDA member, Locker Group, supplied the grade 304 stainless steel panels, which were perforated to 50%. A black painted finish was applied before installation.

With stringent performance characteristics to adhere to, including long-term corrosion resistance and aesthetics, Carl Stahl X-Tend stainless steel mesh was specified for the separation enclosure and the removable curtain within the non-climbable wall. The stainless steel mesh was blackened using an electrolytic process to increase transparency of the enclosure.

Trevor Williams, Lead Consultant of Jackson Teece and Project Architect for the development, said materials selection was critical in delivering the aesthetic appeal and longevity of the enclosure.

“We spoke with Ronstan Tensile Architecture for technical design advice in the early stages of the project. There were various other types of meshes that were a possibility but, being a dynamic structure, alternate materials were far too rigid and not as flexible as the Carl Stahl X-Tend stainless steel mesh. I don’t think we could have achieved this outcome with any other mesh,” Mr Williams said.

“The stainless steel will have a longer life in the aggressive south-facing coastal environment. The blackened mesh has a fantastic form and from an architectural point of view, has achieved an organic appearance.”

Ronstan Tensile Architecture’s contribution to the project, including the tensile mesh enclosure and non-climbable wall, cost about $1.2 million and took 16 weeks to construct.

Mr Murray said the stainless steel demonstrates a great mix of strength and transparency, and the end tensile result is very forgiving.

“Achieving the architectural intent involved complex modelling and finite analysis of the mesh form to ensure the surrounding structures could be designed to support the enclosure loads. Ronstan is absolutely rapt with the state-of-the-art structure,” he said.

The paddock was completely re-landscaped and the impressive exhibit also now features several climbing platforms at varying heights of up to 12 metres, and a 180 kilogram hammock for the chimpanzees to enjoy.

The 17 lucky Taronga Zoo chimpanzees moved in to their renovated home in late September 2011.

QUANTITIES AND GRADES OF STAINLESS STEEL USED

›    Mesh enclosure 770m² of 3mm Ø x 60mm blackened stainless steel, grade 316 Carl Stahl X-Tend mesh.
›    Non-climbable wall facade 140m² of grade 304 stainless steel perforated to 50%, with a black painted finish.
›    Cables 1x19 construction 8mm, 12mm and 22mm diameter, grade 316 stainless steel cables. The stainless steel cable end fittings and  components were polished and passivated prior to installation.

Images courtesy of Ronstan Tensile Architecture.

This article features in Australian Stainless magazine - Issue 50, Summer 2011/12.

Helical Coil Gets a U-Neek Bend

Fabricating equipment for the chemical sector requires solid high quality materials and superior workmanship. In April 2011, ASSDA member and Accredited Fabricator U-Neek Bending Co Pty Ltd put the finishing touches on a radiant helical coil at their factory in Dandenong, Victoria.

The coil, designed as a heater for Titanium Tetrachloride (TiCl4) production, is 11.4 metres long with a diameter of 3.05 metres and required more than 7 tonnes of high grade Inconel Alloy.

U-Neek’s Business Development Manager, John Lovell, said the client chose to have this material shipped from America.
“At around US$1000 a metre, Inconel Alloy is a very expensive option but it has great heat transfer properties and is completely non-corrosive,” Mr Lovell said.

The Western Australian client, who declined to be named, were looking for a fabricator that, in addition to having a proven record in metal bending, could work to their particular requirements for this critical process componet.

“U-Neek weren’t just competitive in pricing,” said Greg, a project engineer with the client. “They succeeded with all the trial projects we sent them.”

“To ensure total quality control, we provided a comprehensive report that detailed every step of the process, including the names of every person who worked on the individual stages,” Mr Lovell said.

U-Neek Engineer Dale Theobold said the coil was manufactured to exacting tolerances using a range of Inconel Alloy materials.
“We used 150NB Schedule 40 seamless 600 for the pipes and flanges, 366-04 WPNCI-S for the elbows, B168-08 for the plate and 253MA for the high temperature pieces,” he said.

Once completed, the coil then had to undergo a rigorous series of tests. The butt welds were verified with full radiography, the attachment welds were submitted to liquid penetrant inspection (LPI), and a full hydro exam was done on the coil itself.

“The coil was filled with distilled water to test its heating capabilities. Then the coil was pressurised with nitrogen, to a dew point of -12°, to remove all traces of water and moisture prior to transporting,” Mr Lovell said.

The transport frame and mounting jigs were manufactured from mild steel. To ensure no cross contamination, Inconel strips were fitted to the mounting points. The coil was lifted onto the back of a semi-trailer for final transportation to Perth, using U-Neek’s 16 tonne travelling overhead cranes.

Images courtesy of U-Neek Bending Co Pty Ltd.

This article features in Australian Stainless magazine - Issue 50, Summer 2011/12.

The Sustainable Score Card for Stainless Steel

The greatest challenge we face is the control of our own success. With 7 billion people on earth, all with an insatiable appetite for a high standard of living, the newest dimension of materials competition is sustainability.

Sustainability is development that meets the needs of the present without compromising the ability of future generations to meet their own needs (UN World Commission on Environment and Development, 1987). In real terms, that means making choices that do minimum damage to our environment, but support a high level of human development.

The built environment is an excellent place to start. Buildings last for a long time, locking up the energy used in making their materials, requiring maintenance and consuming the energy used for heating and air-conditioning. They consume a large proportion of our resources. The choice of materials affects all 3 aspects of consumption, and, a number of building evaluation systems have been created around the world to assist in rating buildings for sustainability. Materials are scored for their energy content reuse during major refurbishment, waste management, recycled content and contribution to the overall design and running costs.

The Green Building Council of Australia rates green buildings for sustainability. The pace of registration and certification is increasing. Of the 368 certified projects, 96 were certified in the last 12 months. The push towards sustainable development in the building sector is strong and accelerating. City of Melbourne’s Council House 2 (CH2) is Australia’s first Green Star rated building to be awarded 6 Stars, which carries an international leadership status. Stainless steel was used to support screening walls of living green plants that shade the building and, required no maintenance or painting, working with the environment to keep good working conditions. Such membranes, containing plants or actively or passively screening the sun, allow the use of a smaller capacity air-conditioning plant, with lower capital costs and ongoing running costs and energy demand.

The only Gold LEED® (Leadership in Energy and Environmental Design) certified meeting venue in the world is the Pittsburgh Convention Centre in the United States. Its grade 316 stainless steel roof is used to harvest rainwater, reducing water demand on the city system - another example of the special properties of stainless steel.

Stainless steel roofing and rainwater goods give extremely low levels of run-off. See Table 1. But this is not the only reason to use stainless steel in the built environment. It contributes to sustainability because of its long service life, excellent corrosion resistance, clean and unchanging appearance and its exceptional hygiene characteristics. Stainless steel is reusable, entirely recyclable, and probably the most recycled product in the world. On top of that, it needs very little cleaning or short or long term maintenance, and makes no contribution to indoor pollution as materials emitting volatile organic compounds (VOCs) do.

There is considerable history and experience of stainless steel service life in the built environment. The Chrysler Building (1930) and Empire State Building (1931) in New York demonstrate the material’s durability, excellent appearance and resistance to corrosion. This extraordinary functionality has been played out many times with a number of examples here in Australia, including the Fujitsu Building in Brisbane, which is clad with 445M2 ferritic stainless steel. Located in a marine industrial environment, this building looks as good as it did on completion in 2002. The long life of stainless steel in these atmospheric applications shows its very high corrosion resistance. The corrosion rate of grade 316 for instance in most atmospheres is is more than 5000 times slower than the rate of carbon steel. See Figure 1 (below).

There is a considerable industry devoted to the collection and recycling of stainless steel products at the end of their life and, scrap is the standard feedstock for making stainless steel. In any stainless steel object, there is an average of 60% recycled content. New production would virtually all be made from recycled stainless steel if it were available, but the growth in the use of stainless steel and its long life in service limit the supply. Table 2 compares the recycled content and end of life capture rate of the industrial metals, and demonstrates that stainless steel is the most recycled industrial metal.

Sustainability is about much more than recycling. The energy used to make the material has a direct impact on sustainability, and all metals are energy intensive. Energy is a scarce resource, generates greenhouse gases and creates specific demands on land use likely to impact on future generations. Longevity and extraordinary recyclability will not be helpful if stainless steels’ energy consumption is much higher than other materials. Figure 2 describes the embodied energy in terms of CO2 equivalent for some of the industrial metals, and shows that stainless has a comparatively high level of embodied energy. In kilogram of CO2 per kilogram of metal, the austenitic grades are over double the footprint of carbon steel, although the ferritic grades are a little less. The footprint of stainless steel is caused by the production of alloying elements nickel and chromium, which are needed to give stainless steel its special properties, including extremely long life. Even so, efforts are ongoing in the stainless steel industry to reduce the energy content.

But in the real world, kilogram CO2  per kilogram metal comparisons are misleading. Take a typical application; a box gutter on a building. The metals have different strength, so are used with different thickness. Stainless steel gives a relatively light weight gutter (see Table 3), and hence the lowest footprint as installed. Coupled with its extended durability without maintenance, stainless comes out as the most sustainable option. Painted galvanised or Zincalume® coated carbon steel has not been included in the table as the calculation of the contributions of the components were too complex, but these materials are highly unlikely to beat the sustainability of stainless steel, even as-installed, and they have a much shorter life.

In summary, stainless steel has excellent recyclability, energy content as-installed (at least as good as other metals), extraordinary longevity and next to no need for maintenance, ever. Add to that the benefits of their special properties, which allow for the construction and operation of buildings at a lower cost. The contribution of stainless steel to sustainability is obvious and considerable.

This article was prepared by ASSDA Technical Committee member, Alex Gouch from Austral Wright Metals.

This technical article is featured in Australian Stainless magazine - Issue 50, Summer 2011/12.

Reflected Glory

Stainless steel’s star has ascended in the public’s conscience as thousands of Westfield Sydney shoppers enjoy the world-class design and materials on show in its newest retail development.

Covering 103,000m2, the $1.2 billion Westfield Sydney development is bound by the Pitt Street Mall and Market and Castlereagh Streets in the heart of Sydney’s CBD. It integrates Westfield Centrepoint, the Centrepoint Convention Centre, Imperial Arcade and Skygarden, plus a new office tower at 85 Castlereagh Street and an extensively modified and refurbished tower at 100 Market Street.

While the size of the project is enormous, it’s the design that’s turning heads. With a nod to lauded international developments in Paris and Frankfurt, the architects of Westfield Sydney have created a stunning environment that makes extensive use of mirror and hairline finished stainless steel in the interior spaces.

Stainless steel was chosen by Westfield’s architects to create a very upmarket, stylish environment for shoppers. In addition to meeting the design intent, stainless steel also offers durability and ease-of-use during construction.

ASSDA Accredited Townsend Group was chosen to design, fabricate and install stainless steel elements throughout the complex, a task it was confident to undertake due to its experience delivering exceptional quality products to exacting clients, such as Apple Inc.

Townsend was awarded the following elements using only 316 grade stainless steel:

›    8,500m2 of mirror-finished stainless steel troughs and particle board infills in the feature ceilings on levels 3 and 4
›    Composite stainless steel panel cladding of the escalators on all levels
›    Black glass and mirror-finished stainless steel on the escalator soffits in void 4
›    Hairline-finished stainless steel composite panel cladding in voids 1 to 10
›    Mirror-finished stainless steel cladding of the elliptical column in void 1 from levels 1 to 5.

The project’s innovative design and engineering required the use of Townsend’s Vee-Cutter, the only one of its type in Australia, to create a very tight radii on the corners on some of the architectural elements. No additional services or treatments were required before or after installation as the stainless steel was procured with a protective film that remained on the product through the manufacturing process until the installation was complete.

Townsend Managing Director and CEO Russ Hill stated that the company was excited when selected for this prestigious development. The complexity of the project presented many challenges which Townsend was able to meet through its skill and experience, resulting in a finish which met the brief set by Westfield and its architects.

Images courtesy of Townsend Group.

This article is featured in Australian Stainless magazine - Issue 50, Summer 2011/12.

Stainless Afloat

Synergy of Lightness and Strength

Artist Wendy Mills’ interest in an ancient Sumerian myth helped bring her vision to reality for a stainless steel sculpture at Willoughby City Council’s new cultural centre.

Described as the cultural home of the North Shore, The Concourse (Chatswood, NSW) incorporates a concert hall, theatre, library, outdoor urban screen, restaurants and retail stores.

Council worked through Pamille Berg Consulting to commission Ms Mills to create an artwork for the library’s water court, which is located below ground level. The 6.1m sculpture, fabricated by ASSDA Accredited Fabrications Australia, is visible from above as well as from within the library.

Fabrications Australia fabricated the sculpture from 50mm x 50mm x 3mm square hollow sections of grade 316 stainless steel and applied a mirror polish. The joins were TIG welded and carefully ground smooth to ensure a high quality finish.

The sculpture is mounted on a ‘blade’ made from 12mm grade 316 plate that was painted to reduce visibility within the water, so the sculpture appears to float on the surface. As the support structure is bolted into the floor immediately above a carpark, extensive water proofing was required.

Ms Mills said the sculpture was more than 2 years in the making from when it was first conceived. Fabrications Australia and Consulting Engineer, Bernie Davis from Opus, worked together with her design to overcome challenges such as the structural support and ensure a proper balance of geometry, constructability and aesthetics.

Mr Davis said it was the team focus on this total balance that ensured a happy client.

Fabrications Australia Director Shannon Molenaar said the project was a true collaboration that evolved over time. Key issues for the fabrication team were structural integrity and long-term durability.

Ms Mills said she chose to work with stainless steel because no coatings were required. She wanted a mirror finish as it requires very little maintenance and it reflects the environment, making the artwork seem lighter.

For this piece, she envisaged a form of transport halfway between a plane and a boat that would sit lightly on the surface of the water as if it is about to take off, yet from above it would appear like a winged insect that has just landed. Her goal was to create a ‘stillness’ – a space for reflection, transition and transformation.

She said her initial concepts of a sky boat and transition tied in beautifully with the Sumerian myth of Inanna and the location within the library water court in the cultural precinct. According to the myth, Inanna (the queen of heaven) travels in her sky-boat to visit Enki (the lord of wisdom) who lives in a watery abyss and gives Inanna divine decrees to transform her city into a new centre of civilisation and culture.

The end result of this successful collaboration is an artwork that purveys a sense of peacefulness while showcasing the versatility and durability of stainless steel in a water environment.

Images courtesy of Wendy Mills.

This article is featured in Australian Stainless magazine - Issue 50, Summer 2011/12.

Brewery to Excel with Local Fabrication

A worrying trend among Australia's major resource companies is the increasing amount of engineering, detailing and fabrication work being sent offshore - a move that has had significant impact on local fabrication. But there are some positive signs in the food and beverage sector that local fabricators are more than capable of meeting design and fabrication expectations.

When ASSDA member and Accredited Fabricator, A&G Engineering, put in a bid to build 10 x 100 hectolitre beer fermenters for Casella Estate - a company best known for their Yellowtail wine label - they had to compete against companies as far away as Europe for the coveted project.

But A&G had a few advantages over the offshore companies: they had worked with Casella before, fabricating 88 x 1.1 million litre wine tanks for the company’s tank farm in Yenda, NSW; they have supplied stainless steel tanks to Australia’s leading breweries, wineries and beverage companies; and they are one of the largest users of stainless steel in Australia.

A&G’s win is an important victory for the Australian industry as a whole and another milestone for A&G Engineering, which was founded in 1963.

The five-month Casella Brewery project, completed in August 2011, saw 25 of A&G’s 200 staff use 65 tonnes of 304 grade stainless steel (including 2-4mm coil and 8mm plate) to build the 10 vessels.

A&G’s Design Manager Heath Woodland said the tanks were designed to AS1210-2010 pressure vessel standards, in order to withstand a pressure rating of 115kPa.

The stainless was welded with A&G’s semi-automated welding process and the internal welds were polished to achieve a 0.6Ra surface finish, to meet beverage industry standards of a food grade finish.

A&G built the vessels at their Griffith and Irymple plants, before transporting them to Yenda. With the beer fermenters now in place, it is hoped the Casella Brewery will be operational by the end of 2011.

Images courtesy of A&G Engineering.

This article is featured in Australian Stainless magazine - Issue 50, Summer 2011/12.

Stainless Course 'Bridging the Gap'

The Regency Institute of TAFE (Elizabeth Campus) in Adelaide has developed an exciting new course that will 'bridge the gap' in knowledge about the welding and fabrication of stainless steel.

Until now there have been only three fabrication and welding training modules available in Australia and they have all applied to light sheet metal. The need for a practical course to teach skills for heavier gauge stainless steel was identified by the Regency Institute of TAFE.

After close consultation with industry, the Regency Institute developed new modules that will fill this need by teaching skills appropriate for upskilling of existing workers and training new ones. Unlike existing courses, which focus on teaching skills to new workers (apprentices) only, this course also targets existing workers.

Three stainless steel welding modules, TIG (tungsten inert gas) welding, MIG (metal inert gas) welding and MMA (manual metal arc) welding have been developed to assist to address the skill shortage.

The modules have been nationally accredited. This allows them to be taken up by learning institutions and organisations Australia-wide and to be accepted as training towards a recognised qualification.

John Coudraye of the Regency Institute of TAFE (Elizabeth Campus) explained the campus was fortunate to have received a capital grant from the South Australian government to purchase capital equipment for the course.

"The grant was given as part of the government's strategic development plan for training," John said.

"Ten of our staff were also sent to Cigweld in Victoria to train for four days in technology and consumables in stainless steel and welding."

The program commences on 3 May, with 12 workers from the Barossa Valley being upskilled. The participants will complete the three modules developed by the Regency Institute of TAFE as well as an additional three light fabrication modules with an emphasis on heavy gauge material.

In addition to its upskilling focus, the course will also be incorporated into apprenticeship training.

Although apprenticeship training is currently available in Melbourne, the Regency Institute of TAFE's course will make a significant contribution to the development of a skilled workforce of stainless steel specialists, particularly important to the growing wine industry in South Australia.

The need for apprentice training in stainless steel was confirmed in 1996 by research conducted by NIETL in conjunction with Melbourne based ASTEP (Alignment of Skills Training to Employment).

At that time, apprentice training focused on various materials (such as carbon steel) and was not meeting the skills needs of stainless steel employers, including the large conglomerate of stainless steel industry in the northern region of Melbourne.

ASTEP conducted a survey which identified a need for full skilling, semiskilling and upgrading of skills in the stainless steel industry.

They chose to focus on full-skilling (apprenticeship) as the underpinning issue. A stainless steel apprentice course was developed with the Northern Melbourne Institute of TAFE and launched in 1997.

Now in its third year, ongoing improvements to the course have seen it develop increased understanding between training providers and participants and their employers, especially through its mentor scheme.

Australia's stainless steel industry employs between 7,000 to 1 0,000 people nationally and adds more than $1.1 billion to the economy each year. These two courses pave the way for further developments in the challenge to provide adequate training to establish a skilled workforce of stainless steel specialists.

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

Stainless Supports Booming Wine Industry

15 million dollars worth of stainless steel has been used to construct the largest rotary fermentation area in Australia.

The facility at Southcorp's Karadoc Winery in Victoria comprises 88 stainless steel red grade processing tanks, pipes and tubes, brine jackets and rotary fermenters.

Southcorp Wines Engineering Manager (Eastern Region) Geoff Leighton said stainless steel was preferred by the wine industry because it is "corrosion resistant, provides a stable environment for the wine, is easy to clean and maintain and has a long service life."

Grade 304 stainless steel was used for the tanks, with a thickness range of 2mm - 6mm, with the highest tank 1 5 metres tall. An extensive amount of 304 and 316 tube was also used.

ASSDA members Atlas Steel (SA), Alfa Laval, APV Valves and James Contract Supplies were all involved in the project.

The expansion brings the Karadoc site's total storage capacity to approximately 93 million litres.

The winery, which produces known brands Lindemans, Queen Adelaide, Kaiser Stuhl and Matthew Lang exports approximately 60% of its bottled wine production.

"The project has provided infrastructure to the district and significant employment opportunities in the areas of viticulture, transport and production facilities," Mr Leighton said.

Mr Leighton said while stainless steel met the needs of the wine industry, there was room for improvement.

"Stainless steel demand exceeds supply on occasions," he said. "It is not totally corrosion resistant and requires diligence in the specification and fabrication process."

The Karadoc project is one example of current growth in the Australian wine industry, which has brought with it exciting opportunities for the stainless steel industry.

Domestic wine production has increased five fold since 1966, from 156 million litres to over 800 million litres.

Vision 2025, a strategic plan by the Australian wine industry, aims to make the industry a global force by achieving $4.5 billion in annual sales of wine and 6.5% of the value of world production by 2025.

Results to date have been positive, with 1999 total sales estimated to be approximately $2.4 billion and 3.5% of the world export volume.

The number and size of fabrication firms in wine growing regions is expanding and as such, real opportunities to explore new applications and methods of design, fabrication and maintenance exist.

To assist the wine and stainless industries meet their objectives, ASSDA is conducting "Using Stainless Steels in the Food Industry" seminar in May and June which will cover fabrication, corrosion, welding, cleaning and sanitation issues for stainless steel use in the food industries as well as issues specific to the wine industry.

For more information on ASSDA's "Using Stainless Steels in the Food Industry" Seminars, please contact ASSDA on (07) 3220 0722.

REFERENCES
1. Australian Wine Foundation (1996) Strategy 2025 - The Australian Wine Industry.

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

Council Impresses With Stainless

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.

75 Tonne Stainless Tank Floor Built to Last

75 tonnes of stainless steel has been used to replace the floor in an enormous tank at QNI Limited's Yabulu Refinery near Townsville in North Queensland.

The tank is one of a series of seven thickener tanks, each of which is 50 metres in diameter. The purpose of the tanks is to form a counter current decant wash circuit for leached ore. Solid tailings are separated from liquor streams in the tanks which act as large settling devices, separating leached ore from a leached solution for the recovery of nickel and cobalt.

When the floor plate of one of the tanks was due to be replaced in June this year, QNI chose stainless steel for the job.

According to QNI's Deputy General Manager lan Skepper, the deciding factors in the choice of stainless were that it was relatively inexpensive and offered increased service life.

"The tanks have been in service for 25 years and the floor plates require replacement on a rolling basis," Mr Skepper said.

"They operate in a harsh environment, holding a solution which consists of strong ammonium hydroxide with up to 15 grams of sulphate per litre heated to 50 degrees celsius. This harsh chemical composition means that the floor plates suffer from severe corrosion and need to be replaced every 10 to 12 years.

"Traditionally we have used mild steel, but chose to use stainless this time because the material cost was not substantially higher particularly when the life expectancy of the floor will double due to the corrosion resistant properties of stainless."

Stainless steel was chosen also for its mechanical robustness and because it can be repaired or modified by workers who possess relatively standard trade skills.

To replace the floor plate, the tank had to be taken offline for six weeks resulting in reduced washing efficiencies and reduced metal recoveries at the refinery during this period.

"Future disruptions to the refinery due to replacements of thickener tank floor plates will now be reduced, because we expect the floor of this tank to last for at least 25 years," Mr Skepper said.

The job involved insitu welding of 5mm sheets of grade 304 stainless laid onto a sand bed.

The stainless steel for the project was supplied by Atlas Steels (Australia) Pty Ltd, Australian Stainless Steel Development Association Levy-paying members.

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

Everlasting Trees Reflect a Shade of Christmas

As we pack up our Christmas decorations, vow to lose those extra kilos gained over the holidays and make plans for the new year, the festive season seems so long ago - not so far for travellers and pedestrians on St Kilda Road in Melbourne.

Perched in front of Central Equity's three new apartment buildings are 12 three metre tall stainless steel trees which, although not specifically designed as Christmas trees, have stylised conical shapes that have a distinctly Christmas 'feel' about them.

Central Equity commissioned Phillip Naughton of Design Inferno to design the trees to complement the prestigious $123 million complex.

"Trees were specifically chosen for the design to reflect the living trees on the boulevard in front of the building," Mr Naughton said.

"They also add a human element to the complex. Because the buildings are 24 stories high, the architects, the Span Group, paid close attention to the surrounding landscape to ensure that they would not be imposing.

"We worked closely with the Span Group when designing the trees so that they would add to the feel of the complex," Mr Naughton said "In fad, unless you look straight up, you don't realise the scale of the buildings because their surrounds are so comfortable."

Stainless steel was chosen for the design for its inherent qualities.

"The design brief specified that the trees had to be low maintenance. Stainless steel fitted this brief as well as adding other qualities such as simplicity and the sense of movement that could be achieved through different surface finishes," Mr Naughton said.

"As one side of each tree is mirror finished, with the other side satin finished, they reflect the seasonal colours of the living trees on the boulevard. They have changed from reflecting little colour through the winter months when the deciduous trees were without leaves, to reflecting the lush green growth of spring."

According to Joe Delacruz of DBM Industries, the trees' fabricator, welding was the most difficult aspect of the fabrication.

"The design of the trees made them susceptible to buckling during welding," Mr Delacruz said.

"To add to the difficulty, the welds had to be invisible."

As part of the careful planning for the job, DBM first built scale models of the trees from timber.

The trees were laser cut and mirror finished at DBM Industries' facility at Reservoir in Victoria. ASSDA members MME Surface Finishing of Seaford in Victoria did the satin finish.

Each tree is made from approximately 400 kilograms of grade 316 stainless steel sheet set into a concrete base which is covered with a 20mm base plate. They are capped with 10 x 30mm capping. ASSDA members Atlas Steels supplied the stainless for the job.

The trees are located on 150 metres of streetscape on St Kilda Road (near the intersection of Toorak Road).

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

"L" and "H" and Standard Grades of Stainless Steels

The common austenitic grades of stainless steel, 304 and 316, are also available with controlled low or high carbon contents, know as "L" and "H" variants, with particular applications.

Low carbon or "L" grades are used to prevent or delay sensitisation  of stainless steel at elevated temperatures and the resulting lower corrosion resistance. The problematic temperature zone is 450-850°C, encountered during welding or specific application environments. "L" grades are often available in thicker selection sizes, greater than about 5mm in flat products.

High carbon or "H" grades are used for higher strength.

Substitution between standard, "L" and "H" grades is often possible allowing many specifications to be met from existing stock.

WHAT "L" GRADES ARE AND WHY THEY ARE USED
The low carbon "L" grades are used where high temperature exposure will occur, including welding of medium or heavy sections. The low carbon is one way of delaying or preventing grain boundary carbide precipitation (often referred to as sensitisation) which can result in intergranular corrosion in corrosive service environments. As shown in the time-temperature-sensitisation curve (right), there is an incubation time before the precipitation of carbides at temperatures in the range of about 450-850°C. The time for precipitation to occur is highly dependent upon the amount of carbon present in the steel, so low carbon content increases resistance to this problem. Because of their application area the "L" grades are most readily available in plate and pipe, but often also in round bar. In the absence of heavy section welding, or of high temperature exposure, the corrosion resistances of the standard and "L" grades are usually identical.

WHAT "H" GRADES ARE AND WHY THEY ARE USED
"H" grades are higher carbon versions of standard grades and have increased strength, particularly at elevated temperatures (generally above 500°C). Long term creep strength is also higher. "H" grades are primarily available in plate and pipe. Applicable grades are most commonly 304H and 316H, but high carbon versions of 309, 310, 321, 347 and 348 are specified in ASTM A240/A240M. These grades are susceptible to sensitisation if held in the temperature range of 450-850°C. Once sensitised, impaired aqueous corrosion resistance and some reduction in ambient temperature ductility and toughness will result (usually irrelevant in high temperature applications).

WHAT THE DIFFERENCES ARE

  1. Composition limits for 304 and 304L are identical except for carbon content (304L does permit up to 12.0%Ni, compared to 10.5% max for 304 -but given the cost of nickel it is usual for both grades to have close to the minimum of 8.5%, so there is no practical difference). Neither grade has a minimum carbon content specified. A carbon content of 0.02% for example complies with both 304 and 304L specifications.
  2. 304H has the same composition specification as 304 except for the carbon range of 0.04-0.1 0% (note the minimum limit for carbon) and that the 304H does not have the 0.10% nitrogen maximum limit which applies to both standard and "L" grades. Also, all austenitic "H" grades must have a grain size of ASTM No. 7 or coarser.
  3. The relationship between 316, 316L and 316H is the same as that between the 304 series of stainless steels. Only the carbon contents differentiate 316, 316L and 316H grades (and the nitrogen and grain size limits mentioned above). Carbon contents are listed in Table 1 (from ASTM A240/A240M). Specifications for some other products, particularly tube and pipe, have a carbon limit of 0.035% or 0.040% maximum for 304L and 316L, but are otherwise the same.

    TABLE 1:
    Grade UNS Number Specified Carbon Content (%)
    304 S30400 0.08 max
    304L S30403 0.030 max
    304H S30409 0.04 - 0.10
    316 S31600 0.08 max
    316L S31603 0.030 max
    316H S31609 0.04 - 0.10


  4. Mechanical property specification differences are illustrated in Table 2 (from ASTM A240/A240M). In practice, steel mills generally ensure that the "L" grade heats meet the strength requirements of standard grades, ie all 304L will have yield/tensile properties above 205/515MPa, so will meet both standard and "L" grade requirements.

    TABLE 2:
    Grade UNS Strength (MPa) min Tensile Strength (MPa) min Yield (%) min Elongation Hardness (HB) max Brinell Hardness (HRB) max Rockwell
    304 S30400 515 205 40 201 92
    304L S30403 485 170 40 201 92
    304H S30409 515 205 40 201 92
    316 S31600 515 205 40 217 95
    316L S31603 485 170 40 217 95
    316H S31609 515 205 40 217 95
  5. Dimensional and other requirements are the same for standard, "L" and "H" grades.
  6. Pressure vessel codes (eg AS 121 O) and pressure piping codes (eg AS4041) give allowable working pressures for each of the grades at nominated elevated temperatures. These codes allow higher pressure ratings for standard grades than for "L" grades. The codes do not permit the use of "L" grades above 525"C (AS4041) or 425"C (AS1210). Both codes include a clause stating that for use above 550"C the standard grades must contain at least 0.04% carbon. 304 or 316 material with 0.02% carbon are therefore not permitted for these elevated  temperatures, whether called "L" or not. At temperatures from ambient up to this high temperature cut-off "L" grade heats with the standard grade pressure ratings would be permitted, so long as the material was in full compliance with the standard grade composition and mechanical property specifications. As discussed above, it is normal practice for this condition to be met.

    The pressure vessel codes give the same allowable pressure rating for "H" grades as for standard grades -this is logical as the "H" grades are simply the standard grades with their carbon contents controlled to the top half of the range, or slightly above.

ALTERNATIVE GRADE USAGE
Because of availability issues it is sometimes desirable to use a product labelled as a standard grade when an "L" or "H" grade has been specified, or vice versa. Substitution can be made under the following conditions:

  1. "L" grades can be used as standard grades so long as the mechanical properties (tensile and yield) conform to the standard grade requirements and high temperature strength is not a requirement. "L" grades usually comply with standard grade requirements, but Mills' test certificates need to be checked on a case by case basis. It is common for steel mills to supply "L" heats when standard grades have been ordered. The practice is legitimate and should  not present problems to fabricators or end users.
  2. Standard grades can be used as "L" grades as long as their carbon content meets the "L" grade maximum limits.
  3. It is increasingly common for "dual certified" products to be stocked - particularly in plate, pipe and bar. These materials fully comply with both 304 and 304L or 316/316L. Dual certified product is deliberately intended to fulfill requirements for both standard and "L" grades, but cannot be used in applications for "H" grade. If an application requires an "H" grade, this must be specified at time of order. Standard grades can often be used in place of "H" grades so long as their carbon contents meet the "H" limits (generally 0.04-0.1 0%). Grain size requirements may have to be satisfied by extra testing. The product and its test certificate may describe it as a standard 304 or 316 unless it was originally manufactured as an "H" grade. Details of the test certificate will confirm grade compliance.
  4. "H" grades can be used as standard grades so long as their carbon contents are 0.08% maximum, and nitrogen 0.10% maximum. This is likely, but would need to be checked.

REFERENCES FOR FURTHER READING
AS 1210
Pressure Vessels

AS 4041
Standard Specification for Pressure Piping

ASTM A240/A240M
Heat-resisting Chromium and Chromium-Nickel
Stainless Steel Plate, Sheet and Strip for Pressure Vessels

This technical article featured in Australian Stainless magazine - Issue 16, August 2000.

Stainless Make Over for Brisbane Landmark

New (and extended) life has been injected into a Brisbane landmark courtesy of a stainless make over worth about $1.2 million. 

In an application believed to be the first of its kind in Queensland, engineers have used grade 316 stainless steel to replace the bearings on Brisbane's Victoria Bridge.

The transition from original carbon steel to stainless has increased the service life of the bearings to at least 50 years from 30 years, giving the Brisbane City Council at least 20 years before the enormous labour and logistical costs of servicing bearings is required.

he bridge, opened in 1969, spans the Brisbane River between the Central Business District and South Bank and is a major arterial link in the city's transport system. Any interruption to traffic flow is disruptive and costly.

Corrosion of the bridge bearings has always been an issue due to its proximity to tidal water and also from the corrosive influence of droppings by pigeons that nest around the bearings.

The Brisbane City Council hired an independent consultant, Dr Nick Stevens, to design the bearings and advise on technical issues associated with their replacement. After consultation with Hercules Engineering the use of stainless steel was recommended.

Principal Asset Officer, Structures, Brisbane City Council. Dr Peter Shaw said although the stainless steel bearings were marginally more expensive than carbon steel, the extended service life offered by stainless negated the Council's initial concerns.

"The initial outlay is completely negligible compared with the extended service life that stainless steel provides and the cost of installation," Dr Shaw said.

"We (the Council) can now wait at least an extra 20, hopefully 50 years before we need to plan such a major operation."

In future the bearings should suffer wear only and hence should require only replacement of the pot This operation should be far cheaper than complete bearing replacement.

Examination of the 30 year old carbon steel bearings showed severe overall corrosion, deep gouge marks and pitting corrosion where the PTFE (teflon) between some of the bearing plates had completely worn away.

Twin pot sliding bearings, and single pot fixed bearings were custom made for the project and installed on site. Grade 316 stainless steel was used for all steel components of the bearings, separated from the mild steel bolts and nuts by synthetic washers. The surfaces on the sliding components of the bearings were polished to a mirror finish to minimise friction.

Grade 304 stainless steel woven mesh was installed around the bearings to keep the pigeons out and further protect against corrosion.

The bearings were fabricated by Hercules Engineering in Sydney with stainless steel supplied by ASSDA member Sandvik Australia.

This article featured in Australian Stainless magazine - Issue 16, August 2000.

Livable Art

A Melbourne artist and designer is using stainless steel to blur the lines between form and functionality. 

Colin Kirkpatrick from Modifie Designs adapts geometric shapes inspired by sculpture to create works that can transform from conversation pieces to coffee tables in seconds.

Cubes and three dimensional rectangular shapes are fabricated from grade 304 stainless steel sheeting welded to a timber subframe, then attached to castors for mobility and versatility.

The custom-sized shapes can be used as either furniture or sculpture and as a single unit or separated into individual pieces.

The Modifie range also includes coffee tables with stainless steel frames contrasted by glass, marble, sandstone or bluestone tops.

As versatile as the cubes, the coffee tables can also be stacked to form shelves and storage units.

Of crucial importance to Kirkpatrick is that as well as being aesthetically pleasing, his work be functional, a criteria met through design and the use of stainless steel.

'I love the cleanliness and exclusive look of stainless," Mr Kirkpatrick said.

"The material complements perfectly the angles, smooth surfaces and form of the furniture."

Each piece is designed and fabricated by Kirkpatrick in his Highett workshop using primarily grade 304 stainless steel, TlG welded top and bottom and polished with a No. 4 finish.

Kirkpatrick's work is available from a number of furniture stores in Sydney and Melbourne, including Orsson & Blake in Sydney, Blend Furniture in Collingwood, Urban Attitude in St Kilda, Crowded House Design in Malvern, Cochrane & Galloway in Hawthorn and Outhouse in Fitzroy.

He plans to extend the range to include multi-fundional, adaptable entertainment units and storage units, all made from stainless steel.

"In my opinion, not many other materials have the exclusivity of appearance and style that stainless steel has," Mr Kirkpatrick said.

Stainless steel used for the furniture is supplied by ASSDA member Dalsteel Stainless.

This article featured in Australian Stainless magazine - Issue 16, August 2000.

Let the Games Begin!

When millions around the world watch the Sydney Olympic Games this September, they will also be experiencing the best of Australian architecture, with particular emphasis on stainless steel.

Stadium Australia, located at Homebush Bay in Sydney's inner city in the centrepiece of the Olympic site. Here, events such as the opening and closing ceremonies and the track and field program will be played out. Closer examination of the sit reveals the use of stainless steel in a myriad of applications, both aesthetic and functional. Perhaps more importantly, the use of stainless steel helps meet the organiser's "green" commitment: to use materials with minimal impact on the environment and designs that reduce waste and conserve resources.

THE STADIUM
Seating 110,000, Stadium Australia is the largest stadium in the history of the Olympic Games. To give an idea of its size, the two main curved trusses span 296 metres and four Boeing 747s would fit side by side under the span of the main arch.

The roofing material was supplied by ASSDA member Atlas Steels (Australia) Pty Ltd, the handrails by ASSDA member Sandvik Australia.

Nineteen lighting towers, representing the number of cities in which the Olympic Games have been held to date, stand like sentinels guarding the entrance to Stadium Australia.

The towers consist mostly of concrete and painted steel, but grade 316 stainless steel rods, 25 millimetres in diameter, provide tension in each corner, while 316 doors and infill panels, with a No. 4 finish, exist at ground level.

The names of each of the cities where the Games have been held are glass-bead blasted on to grade 316 sheet with a No. 4 finish.

These towers each carry solar panels that contribute to the public elecricity grid an amount of power equal to that consumed by the towers at night.

At the bottom of one of the towers is a Munich Memorial to honour the athletes who died at the 1972 Munich Olympics. The memorial consists of three plaques fabricated from grade 316 stainless steel and glass, the names being engraved and paint filled in a surface with a No. 4 finish. Stainless steel channel sections, glass bead blasted on the inside and mirror polished were used around some of the edges.

Spread over six levels, the kitchens at Stadium Australia will see almost as much action as the field! Anticipated to feed about 110,000 people every day during competition, the kitchens have been fitted out with stainless steel equipment including benches, exhaust hoods, 200 deep-fat fryers and 300 upright refrigerators. ASSDA members Curtin Foodservice Equipment Pty Ltd supplied a bulk of the equipment, including over four and a half kilometres of stainless steel benches, 145 stainless steel hi-velocity extraction hoods, 200 deep-fat fryers, bain maries, refrigeration equipment, bulk and plated hot food holding carts and more than 200 mobile trolleys. Grade 304 stainless steel for the equipment was provided by ASSDA member Fagersta Steel.

THE OLYMPIC VILLAGE
Home to 15,000 athletes, officials and coaches during competition, the Olympic Village reflects stainless steel's contribution to the "Green Games". 6,000 kilograms (10,500 square metres) of grade 316 stainless steel mesh were installed to provide a chemical-free termite barrier to over 500 houses in the Village.

Fabricated and installed by Termi-Mesh Sydney Pty Ltd, the stainless steel mesh provides a physical barrier around the building perimeter and is collar clamped to pipes and other entry points. The result is a permanent obstruction to termites that eliminates the use of potentially dangerous chemicals.

OLYMPIC BOULEVARD
Olympic Boulevard, which passes key venues such as Stadium Australia and the Aquatic Centre, features spectacular fountains with stainless steel components.

Water jets, each covered by a grade 316 stainless steel cowl, provide a cascading arch at Fig Grove.

Fabricated grade 316 stainless steel gratings, black chrome plated so they are almost invisible under water, are used as safety screens. Grade 316 sections are also used to ensure the water cascades evenly along the length of the feature and as structural supports.

At the far end of the Boulevard is a fountain featuring lines of tubular water jets. Each jet comprises an inner structure of grade 316 stainless steel tubes clad with 3 millimetre thick 316 sheet, formed into a tapered cylindrical section with a No. 4 finish.

The underground pump house receives fresh air through spiral, welded ducting consisting of 250 millimetre diameter grade 316 stainless steel. A nearby wooden viewing pier has 316 handrails on galvanised steel uprights.

THE TORCH
Perhaps the most evocative symbol of the Games is the Olympic Torch, which carries the flame from Olympia in Greece to Stadium Australia, via the Olympic Torch Relay.

he design of the approximately 1 kilogram, 72 centimetre tall torch includes three layers representing earth, fire and water. The inner layer is polished stainless steel, the middle layer anodized aluminium and the outer layer specially coated aluminium.

Thin grade 316 stainless steel strip was used to form a skin inside the grade 430 stainless steel tube inner layer, acting as a shield against heat, wind and rain. Also, very fine (25 micron opening) 316 stainless steel gauze was installed as a final filter to clean the liquid propane/butane gas mixture that fuels the torch, thereby preventing contaminants from extinguishing the flame.

The torch was fabricated by Sydney firm GA & L Harrington, who produced over 14,000 torches available for purchase by the 10,000 runners participating in the Torch Relay.

This article featured in Australian Stainless magazine - Issue 16, August 2000.

Stainless Welcome for Sports Fans

Sports fans trekking to Melbourne's Colonial Stadium will enter the ground via a 200 metre long, 20 metre wide bridge shrouded in stainless. 

The Bourke Street Pedestrian Bridge, which connects Spencer Street Station to the eastern entrance of the $460 million sporting arena, opened in March 2000, makes extensive use of stainless steel to stunning effect.

A 200 metre long canopy comprising 14 rolled cascading stainless steel sheets divided in sections by red coated curved steel antlers protects pedestrians queuing on the south side of the bridge. The antlers, made from carbon steel, provide lighting and primary support to the stainless steel canopy.

400 metres of stainless steel handrailing with balustrades run the length of each side of the bridge.

he bridge connects the Gateway to the east and adjacent Spencer Street Station and extends across the station to the West End Connection above North-South Road.

Pedestrians entering the 30 000 person capacity bridge on the station side are greeted by two red glass towers, large staircases and a crushed wall of stainless steel through which a ramp connects disabled access from street level to the bridge.

Wood Marsh, the firm commissioned to design the bridge, said stainless steel was chosen because of its appearance, low maintenance and longevity.

"With thousands of people expected to cross the bridge every time an event is on, we needed a material that would not only withstand this level of traffic, but would make an eye-catching entrance to the stadium."

"Stainless steel was the obvious material choice -it is durable, needs limited upkeep and achieved the look we were after."

The roof cladding consists of 20 tonnes of 1.6mm grade 316 stainless steel sheets rolled to a radius of approximately 325mm butt joined, with a No. 4 finish to both faces.

400 metres of 6 inch, Sched 40 grade 316 stainless steel pipe was used for the handrails, polished to a No. 4 finish.

The handrails were constructed at Shearform Industries' workshop and installed, invisibly fixed, on site. The roof cladding was fabricated and polished in the workshop and installed on site.

The roofing material was supplied by ASSDA member Atlas Steels (Australia) Pty Ltd, the handrails by ASSDA member Sandvik Australia.

This article featured in Australian Stainless magazine - Issue 17, January 2001.

New Pulp Mill Relies on Stainless

1,200 tonnes of stainless steel plate and coil and over 47,000 metres of stainless steel pipe and tube has been used in the construction of a new $400 million unbleached pulp and paper mill in Tumut, New South Wales. 

The Visy Pulp and Paper Mill will produce 240,000 tonnes of unbleached kraft pulp and packaging paper annually, to be supplied to domestic and overseas markets.

Raw materials for the plant will come from local plantation timber sawmill residues and pulp materials from softwood plantations, and supplemented by domestic and commercially derived waste paper. The plant is being built using the latest technology, meeting the highest environmental standards.

Grades 304, 316 and 2507 stainless steel were used in pipes, storage tanks and vessels in the process area of the mill.

Approximately 1,200 tonnes of stainless steel plate and coil, ranging in thickness from three millimetres to 38 millimetres were used for the storage tanks. The storage tanks, 50 in total, have a capacity of nearly 30 000 cubic metres.

Grade 2507 stainless steel was used in smaller vessels that will contain highly concentrated liquids, sodium and potassium salts at high temperatures.

Visy Project Technical Manager Austin Davey said: "The combination of temperature and salt meant that 2507 was the only suitable material for the job."

304 stainless steel pipes will carry raw water, some chemicals and pulp used in the process.

Mr Davey said as well as its ability to deal with high temperatures and the corrosive environment of the plant, stainless steel was chosen for its cost-effectiveness and long life.

"We designed the mill to have at least a 30 year life, that's why we chose stainless," he said.

"We always look for the most cost-effective method for our projects.

"At the time of purchase, the price of stainless steel was very competitive and helped make the decision easy."

Fabrication was undertaken by a number of different companies in New South Wales, Queensland and Victoria.

Some of the piping for the mill was supplied by ASSDA member Skinner Engineering, with some storage tanks and vessels supplied by ASSDA members D&R Stainless and JC Butka Engineering Pty Ltd.

The majority of stainless steel used in the project was supplied by ASSDA member Sandvik Australia, with a proportion of the design work undertaken by ASSDA member Kvaerner.

Mr Davey said end users of stainless steel experience supply problems that he believes impact on the popularity of the material.

"Not all the materials or product forms are stocked in Australia. Lead times, availability and price movements must be watched."

The mill is expected to begin paper production in the middle of 2001.

This article featured in Australian Stainless magazine - Issue 17, January 2001.