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Council Solves Fishy Problem with Stainless

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.

Cleaning and Protecting Stainless Sculptures

"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.

Cleaning of exterior stainless steel

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 This email address is being protected from spambots. You need JavaScript enabled to view it.

New 9kg Stainless Steel Gas Bottles


Posted 31 October 2005

Strong demand from prestige boating and yachting manufacturers has prompted the production and release of new stainless steel nine kilogram LPG gas bottles.

Melbourne-based fabricator and ASSDA member, Stainless Tanks and Pressure Vessels (STPV) produce grade 316L stainless steel gas bottles that offer significant resistance to corrosion, making the product ideal for cooking in marine and boating applications.

The new gas bottles will also complement the increased production of barbecues now manufactured in stainless steel and are supplied with standard gas fittings.

The refillable gas bottles have a ten year inspection life in line with industry codes and comply with gas liquids code under AS 2470.

STPV principal Chris Miller said he commenced manufacturing the gas bottles after enquiries from a number of prestige boating and yachting manufacturers in search of a superior, corrosion resistant supply tank, which can readily be refilled.

“We have since commenced supplying several barbecue manufacturers who produce a range of superior products in stainless.”

The stainless steel bottles are available from Southern Stainless, Gold Coast and Marine Barbecues, Newcastle. Alternatively, contact Stainless Tanks and Pressure Vessels for outlets.

Stainless Tanks and Pressure Vessels manufactures a wide range of standard and to order stainless steel tankage equipment for the fire protection, process industries and numerous industrial applications.

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

Specifying Stainless Steel for Luxury Beachside Homes

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.

Preventing Coastal Corrosion (Tea Staining)

When used properly, stainless steel enjoys a strong and enduring reputation for visual appeal and structural integrity in a wide range of applications and environments.

But, like all materials, stainless steel may become stained or discoloured over time, impairing the overall look. This brown discolouration - tea staining - has been identified in coastal applications in Australia and overseas.

Factors affecting tea staining have been researched by ASSDA and the information gathered has been supported by experiences from around the world.

This article provides information on tea staining and what fabricators, specifiers and end users should do to help avoid it and enjoy the long life and clean appearance of stainless steel.

WHAT IS TEA STAINING?
Tea staining is discolouration of the surface of stainless steel by corrosion. It is a cosmetic issue that does not affect the structural integrity or the lifetime of the material. Tea staining occurs most commonly within about five kilometres of the surf and becomes progressively worse closer to the marine source.

However, wind exposure, pollution levels, local sheltering and higher temperatures can create environments where tea staining might occur 20 kilometres or more from the surf. The effect is much less severe around sheltered bays. These same factors also increase corrosion rates of alternative materials.

Other causes of staining that are not tea staining include carbon steel contamination, uncleaned welds and chemical fumes such as hydrochloric acid or bleach. The ASSDA Reference Manual has more details on this.

WHY DOES TEA STAINING OCCUR?
The relationships between the contributing factors are complex, but generally become increasingly critical closer to salty water. Tea staining occurs when local conditions (such as temperature, relative humidity and presence of corrosive substances on the surface) are too aggressive for that stainless steel grade in its installed condition.

There are important factors that promote the occurrence of tea staining that should be considered, as shown in the box and explained below.

1.    Presence of corrosive substances
The presence of sea salt on the surface of the stainless steel is one of the major factors that causes tea staining. Sea salt has the characteristic of staying wet until a very low relative humidity (RH). The result of this is that the surface stays wet (and is corroding) longer with sea salt compared with sodium chloride. However, presence of industrial pollutants could also make the conditions more aggressive.

2.    Atmospheric conditions
A combination of atmospheric conditions with high humidity (eg tropical climates) and a high temperature creates worse conditions for the occurrence of tea staining. The high humidity generates a film of moisture that dissolves the salt deposits and creates a corrosive solution on the surface. The low humidity and absence of corrosive deposits means that tea staining is rarely a problem indoors.

3.    Surface orientation and design
Poor drainage promotes corrosion whether it is because the surface is near horizontal or has a texture that traps contaminants. Conditions are very aggressive in rain sheltered areas such as the underside of sloping roofs, downpipes under eaves or in a building rain shadow. These can cause significant tea staining. Designs with corners or crevices (such as intermittent welds) can trap water and lead to more serious corrosion than tea staining.

4.    Surface roughness
Deep grooves or metal folds on a surface are more susceptible to corrosion because they can trap salts (chlorides). When the surface dries the salts become concentrated, making the conditions more aggressive. A deep groove will have more trapped water (and salts) so the bottom of the groove will be exposed to salt concentration above its resistance for longer - which will initiate corrosion. There is a critical surface roughness of approximately 0.5 μm Ra for cut or abraded surfaces. Abraded surfaces smoother than approximately 0.5µm Ra are much less susceptible to corrosion.

5.    Surface characteristics
To achieve the best corrosion performance of a stainless steel, the surface should be clean, free of contamination such as carbon steel swarf or manganese sulphide inclusions, and have a continuous passive layer. Acid pickling, acid passivation or electropolishing for sufficient time will remove these contaminants from the surface as well as restore the passive layer, leaving the stainless steel with a clean and corrosion resistant surface. If a stainless steel is welded, the heat input will locally destroy the passive layer (a dark non-protective oxide is formed around the weld). To achieve best corrosion performance and restore passivity of the weld, the heat tint and underlying chromium depleted layer must be removed. How this is done is described later.

6.    Appropriate grade
There are several hundred grades of stainless steel with different chemical composition but only about 10 in common use. All owe their corrosion resistance to the thin chromium oxide film on the surface, although other additions such as molybdenum and nitrogen can improve the corrosion resistance, especially in chloride-containing environments. A formula based on the content of these three elements is useful to rank the corrosion resistance of different grades. This Pitting Resistance Equivalent [PRE] number is calculated by %Chromium + 3.3 %Molybdenum + 16 %Nitrogen. The PRE ranges from 10.5 for the grades with the lowest corrosion resistance to more than 40. For acceptable corrosion resistance, typically a PRE of approximately 18 is adequate away from marine influences, PRE of approximately 24 is required for marine atmospheres while severe marine atmospheres may require PRE of approximately 34. The higher the PRE, the greater the corrosion resistance.

7.    Maintenance
Stainless steel is a low maintenance material but it is not generally maintenance free. A light and regular wash is best and natural rain washing may be sufficient. If not, then consider washing the stainless steel when you wash an adjacent window. Lower grades will require more regular maintenance and if the environment causes sticky deposits, a solvent and detergent mix may be required. Application of oils or waxes will temporarily restrict chloride access to the stainless steel but they need regular renewal. These temporary protectives also tend to attract debris and dull the surface.

CONDITIONS REDUCING THE RISK OF TEA STAINING

1.    Absence of corrosives - especially salt.
2.    Atmospheric conditions - lower temperatures and low relative humidity (RH) are better.
3.    Surface orientation and design - free drainage and avoidance of traps which can concentrate corrosives. This includes open exposure to allow   rain washing.
4.    Surface roughness - smoother is better.
5.    Chemical cleanliness or passivation of the surface improves the corrosion resistance.
6.    Appropriate grade for exposure conditions - increasing PRE increases corrosion resistance.
7.    Maintenance - or corrosives will accumulate.

GUIDANCE IN FABRICATION

Design, fabrication and handling
Poor design and fabrication can lead to tea staining or more serious corrosion of stainless steels. Surfaces should be free draining, boldly exposed to rain washing and avoid channelling of run-off. Horizontal surfaces or curves which cause ponding are specific problems. Abraded surfaces should not be rougher than 0.5µm Ra and the grain should be vertical to avoid ponding and collection of contaminants. For abraded surfaces, the best corrosion resistance will be achieved if a nitric acid passivation treatment is carried out as a final step.

Competent stainless steel fabricators will avoid carbon steel contamination (which can cause other corrosion problems), so choose designers and fabricators that are experienced with stainless steel to achieve the best outcome.

Appropriate grade selection
Each stainless steel has a limit to the concentration of salts that it can comfortably resist: the higher the alloying content (Cr, Mo and N), the higher the resistance to corrosion. Exposure of a particular grade of stainless steel to a more aggressive environment than it can resist will cause tea staining.

Grade 316, or a grade with equivalent corrosion resistance, should be selected as a minimum within five kilometres of the surf. For critical applications (eg splash zones, unwashed areas or rough surfaces), higher grades of stainless steel such as duplex or ‘super’ grades may be required.

The lower alloyed and less expensive grades (such as 304 or 430) will probably become tea stained or even suffer more severe corrosion in a marine environment.

Treatment of welds
Pickling after welding is one method of promoting good performance of stainless steel near the coast. This chemical treatment normally uses a mixture of nitric and hydrofluoric acid in a gel, paste or bath. It removes the welding oxide and chromium depleted layer underneath and rapidly restores the passive layer, which gives stainless steel its corrosion resistance. A darker heat tint means a thicker oxide and a longer exposure to pickling acids is required. Pickling removes material from the surface in a controlled way and may etch and dull the stainless steel surface. Excellent gas shielding, so there is no more than a pale straw colour, may avoid pickling provided the environment is mild. An alternative is to mechanically remove the scale and underlying chromium depleted layer, followed by a chemical passivation treatment using nitric acid. Any mechanical removal must not unduly roughen the surface.

Installation and inspection
After installation, the completed structure should be visually inspected for surface damage or contaminants. If contamination is suspected, several cycles of a misting and drying test with tap water is relatively simple. The sensitive ferroxyl test (described In ASTM A380) may also be used in critical applications. If discovered, imperfections should be removed and the corrosion resistance chemically restored by pickling or passivating treatments or by electropolishing.

Do not use hydrochloric acid
Hydrochloric acid, sometimes used to clean cement or mortar residues, must not be used on stainless steel — it will stain the surface and usually start more serious corrosion.  

KEY DESIGN RECOMMENDATIONS

Plan to get the desired result
Marine environments are the most aggressive for all building materials.
Stainless steel’s corrosion resistance in marine environments means that installations are likely to remain structurally sound for decades (see image on right).

It must be recognised, however, that keeping a pristine surface finish requires understanding and, usually, additional cost. Determine your expectation of the structure and plan ahead to achieve and maintain the intended result. This normally includes a maintenance program.

Environment
Tea staining is most likely to occur up to five kilometres from a surf beach and one kilometre from still marine waters. There is no hard and fast rule: wind and weather conditions play a big part and the severity of the conditions increases sharply as you approach the surf. AS 2312 suggests that in some special circumstances, 20 kilometres from the coast can still constitute a marine environment. The closer to the source of salt, the more critical it is to follow the recommendations in this Bulletin.
Areas that are sheltered or not rain washed are particularly susceptible. Tropical and high humidity areas are also more at risk of tea staining.

Specify and insist on a smooth and clean surface finish
To minimise the risk for tea staining the smoother the surface the better. A surface roughness of less than 0.5µm Ra  is strongly recomended. Surfaces smoother than 0.5µm Ra will have even better corrosion resistance. The most corrosion resistant, mechanically finished surface is a mirror polish (ASTM A480 No.8 or EN10088.2 class 2P). It is very smooth, resistant to salt accumulation and easy to clean. The surface roughness of a mirror polished surface is so low that it is not reliably measurable by mechanical (stylus) instruments.
A No.4 finish just means an abraded (linished) finish. Specifying a No.4 finish is inadequate without indicating the required roughness.  
The Euronorm standard EN10088.2 (finish 2K) recognises this and requires Ra<0.5µm but also that the abraded profile is a clean cut.

Components used near the sea can be made more resistant to tea staining if they are passivated to remove surface contaminants such as steel smears, weld spatter or sulphide inclusions. Mild levels of contamination may be removed by nitric acid passivation which should not change the surface appearance although it may slightly cloud a mirror polish. More severe contamination by particles of steel or grinding debris may require pickling which etches and usually dulls the surface. Either process may use pastes or gels (which can be applied on site) or liquids in baths in a factory. These chemical processes take longer if it is cold.

Electropolishing has been found to be extremely effective in removing surface contamination and passivating the surface. It also brightens and slightly smoothes the surface as well as rounding sharp edges and removing the peaks left from polishing operations. Electropolished surfaces have a characteristic lustre but may not be mirror smooth. A mechanically mirror polished surface will normally lose its mirror reflectance if electropolished.

Smoother mill finishes such as 2B and Bright Annealed (BA) are widely available in flat products. Provided they are not damaged during fabrication, they offer good resistance to collection of salt deposits and hence to tea staining.
Rolled embossed finishes may be suitable for some applications. These have very smooth surfaces but with a pattern that lowers reflectivity. Think carefully about the pattern and how it will be oriented — avoid pools of water sitting on the surface.

Specify and insist on the right grade
In marine environments, use grade 316 or one with equivalent corrosion resistance unless the job is aesthetically critical and regular maintenance is unlikely.

Where there are high aesthetic expectations a number of more corrosion resistant stainless steel grades can be considered. The first step up from 316 is 2205 and then the super duplex grades, although the high molybdenum austenitics and high molybdenum ferritics may also be useful. Smooth surface finish and maintenance are still important with these grades.

Treatment of welds
For general architectural applications welds should comply with AS/NZS 1554.6 Level 2, Class B. (Details of other weld finish classifications are given in the ASSDA Reference Manual). However, this specification does not guarantee the absence of structurally minor surface defects which can act as traps and corrosion initiating sites. The protruding weld can be ground flush, and good resistance to tea staining achieved (a Grade I finish) when polished to 320 grit or finer finish. The smoother the surface, the better the tea staining resistance. Passivation will occur in chloride free, moist air within a day. Chemical passivation treatment with nitric acid may be applied to:

  • Substantially reduce the time required for passivation
  • Provide a more corrosion resistant passive film
  • Remove possible iron contamination
  • Dissolve exposed manganese sulphide


Chemical passivation must be applied after abrasion if the environment is particularly aggressive.
An alternative cleaning treatment is a Grade II blast cleaned finish. This will require a post blasting passivation treatment. The blasting should remove heat tint and the chromium depleted layer but not make the surface roughness worse than 0.5 µm Ra, must not leave folds or crevices and should not embed corrodents. The Grade II stainless steel wire brushing treatment is not adequate to control tea staining.

Where a polished (or linished or ground) finish is desired, abrasives should be used with lubrication if possible. In selecting abrasives, consideration should be given to matching the surrounding finish.

A Grade II pickled finish will provide good tea staining resistance without grinding the weld flush, provided there are no significant surface crevices/defects. Where linishing or blasting is not performed, pickling of site welds (using mixed hydrofluoric plus nitric acids) should take place as a final step in the weld procedure.

Pickling will remove any fabrication contaminants and restore the passive chromium oxide layer, resulting in a corrosion resistant surface. Electrocleaning has been used instead of pickling to remove weld scale and heat tint, especially when hydrofluoric acid use is restricted. While passivation treatments do not normally affect appearance, pickling treatments are likely to dull bright surface finishes. Electropolishing is also a very effective method of passivation. ASSDA's Australian Stainless Reference Manual describes these treatments in more detail.

Specify and insist on regular maintenance
Washing removes deposits (such as salt) that can cause corrosion. It is necessary to avoid tea staining. Rain washing the surface is helpful in reducing tea staining, so design the job to take advantage of the rain, but ensure good and even drainage.

Stipulate that the stainless steel also be washed when cleaning of the surrounding area takes place. As a guide, stainless steel should be washed if a window requires washing. For best results, wash with soap or mild detergent and warm water followed by rinsing with clean cold water. The appearance of the surface can be improved further if the washed surface is wiped dry.

If routine cleaning of the surrounding area does not take place, washing frequency for the stainless steel is recommended as in Table 1 below.

It is essential that abrasive cleaners or those containing chlorides or bleach are NOT used to clean stainless steels as they will damage the surface. If some tea staining does occur, then an assessment of the 7 points is required to determine why the problem occurred. Simple mechanical polishing is unlikely to both remove current and prevent future teastaining. Reasonably simple chemical cleaning and passivation is usually the most effective treatment. ASSDA's Australian Stainless Reference Manual has more details.

Download ASSDA Technical FAQ6: Preventing Coastal Corrosion (Tea Staining) (Edition 3, Feb 2010)

Further Reading

ASSDA's Australian Stainless Reference Manual Edition 7, 2012

Australian Standard AS/NZS 1554.6 Welding Stainless Steel for Structural Purposes

ASTM Standard A380 Standard Practice for Cleaning, Descaling and Passivation of Stainless Steel Parts, Equipment and Systems

Nickel Institute, Japan Stainless Steel Association Successful Use of Stainless Steel Building Materials publication No 12 013

Nickel Institute Guidelines for the Welded Fabrication of Nickel-containing Stainless Steels for Corrosion Resistant Services publication No 11 007.

Gold Coast's Kirra Point: Looking Great Six Years On

When the Gold Coast City Council was seeking a stable and visually stunning medium for use on their Kirra Point board walk project in 1999, they looked no further than stainless steel and after six years in service, it still looks great.

 

Council engineers chose stainless steel for the upright posts and moveable handrail system for safety, corrosion resistance and aesthetic reasons.

When designing the project, the board walk had to take into account a steep vertical drop to the beach below - an important safety issue met by using stainless steel handrailing.

The board walk project was undertaken in two stages, the first of which involved constructing a concrete walkway and handrails along the Kirra Point foreshore. The second stage saw the construction of a timber board walk out over the foreshore onto the beach.

ASSDA Accredited Fabricator, Stoddart (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.

The knowledge that ASSDA requires for its Accreditation Scheme was used in the execution of the structure, ensuring the ongoing satisfaction of the Council with minimal maintenance.

This article featured in Australian Stainless magazine - Issue 35, Autumn 2006.

445M2: A New Generation Stainless Steel (Part 1)

This article is the first in a series showcasing the uses of 445M2 stainless steel. Read Part 2. Read Part 3.

Australians' love of the water has always provided challenges to the construction industry, particularly when it comes to choosing materials that can be used in aggressive environments such as near the coast or swimming pools.

Stainless steel grades 316 and 304 have long been the obvious solution in these applications, but the key factors of formability, cost and corrosion resistance are now shining the spotlight on an alternative grade.

445M2 stainless steel has been used in Australia for a number of years for roofing and walling applications, and its characteristics are now proving useful for a broader range of applications.

The material, supplied by ASSDA member Austral Wright Metals, is being used by Dunning Engineering Services Pty Ltd for a range of stainless steel pergola brackets.

Dunnings - a South Australian based manufacturer of builders and plumbers hardware, who also operate a sheet metal pressing and fabrication facility - developed the range in response to the growing demand for better corrosion-resistant products that can be used in aggressive environments.

The company experimented with punching and bending various grades of stainless steel, including 316, but it was 445M2's formability that provided the crisp, clean angles they were seeking, with the advantage of reduced tool wear.æ Dunnings was also able to fabricate with existing tooling and machinery, avoiding the prohibitive cost of new dies and tooling.

More importantly, 445M2 is a marine grade stainless steel with the corrosion resistance of 316 or better and a cost that falls between 304 and 316.

Dunning spokesperson John Gill said 445M2 resisted the salt from the surf, and gave safe performance over a long life - even when painted.

"Due to the formability of 445M2, the savings to our business have been enormous and we are now looking at other areas where 445M2 could be applied."

This article featured in Australian Stainless magazine - Issue 37, Spring 2006.

A Great Aussie Tradition Makes its Way

For those who love to indulge in a life of sun, surf and sand the idea of placing a barbeque in such rust-promising environments is not often an option as their longevity is compromised.

But Gold Coast company Southern Stainless has bridged the gap between a nautical lifestyle and the great Aussie tradition by manufacturing barbeques in stainless steel.

ASSDA member Southern Stainless typically specialises in the manufacture of stainless steel products including wine storage and fermentation tanks and marine fitouts, but supplying stainless steel barbeques, boat mounting systems and accessories to the general public, wholesalers, retailers and building industry has proven to be one of their fastest growth areas.

The barbeques are made from 316  grade stainless steel, with a  2205 duplex grade stainless steel plate, which is more corrosion resistant and easier to clean.

The barbeques are fully welded to enhance strength and use an electropolished finish to aid in corrosion resistance and provide a durable surface.

Southern Stainless Managing Director Phillip Brown says the barbeques can be designed to suit customer requirements and are 100% Australian owned and made.

“Chinese manufacturers retail theirs slighty under our price,” Phillip says.  “A certain percentage of the market will always go for the cheaper alternative, but when consumers are looking for quality, they tend to stick with locally-made products.”

This article featured in Australian Stainless magazine - Issue 38, Summer 2006.

Whale of a Time

Longevity won’t be an issue with the latest version of this sculpture. Cherry Blossom first appeared as an ice sculpture - complete with spinning cogs - in the 2008 Russian Ice Cup.

After winning the Mayor’s prize its creator, Melbourne-based artist Benjamin Gilbert, constructed a stainless steel version for Bondi’s “Sculpture by the Sea” exhibition.

ASSDA Member Atlas Steels sponsored the project, providing 316 stainless to suit the coastal environment.

Mr Gilbert specified stainless steel for its neutral colour, polishing the surface with stainless wire brushes to allow salts to build up. 

“I don’t really like shiny stainless finishes. A patina is more realistic and neutralises visual effects from its surroundings,” he said.

The panels were both TIG and MIG welded, pickled and polished to achieve a buffed silver leaf effect.

“The work is a combination of Harold Holt mystery and my work with Greenpeace and the Wilderness Society,” Mr Gilbert said.

“It is the first large work I’ve made purely for my own satisfaction in years.”

Cherry Blossom is showing at Canberra’s Corinbank Arts Festival in late February and will then travel to Europe for Denmark’s version of “Sculpture by the Sea” in May.

This article featured in Australian Stainless magazine - Issue 45, Summer 2009.

Stainless revamp for Sunshine Coast beach

A revamp of Kings Beach in Caloundra, QLD, has had a gleaming response, with stainless steel a major contributor to the brand new look.

Kings BeachInitial stages included new seats, hand railing and some draining, but the most recent instalment  focussed on the beach-side swimming pool and recreational area with balustrades all around. Although 2 or 3 different builders have been used during the project to date,

ASSDA Accredited Fabricator Paige Stainless was involved with all stages. Kilometres of stainless steel tube was used to fence the 98 metre pool circumference with top and bottom rails and railings.

“There was also some peripheral work, such as seats and railings that lead into the pool area,” says Kevin Finn of Paige Stainless.

Kevin says that whilst the end result of stainless steel looks great, the builders had little choice but to use the material.

“They did look at aluminium for the pool fencing.  Stainless steel was certainly the most expensive but with the corrosive environment and longevity required, it was imperative that they use stainless steel.”

The project used only grade 316, supplied by ASSDA members Atlas Specialty Metals and Tube Sales at both 600 and 800 grit polishes to  help prevent tea staining.

The unique setting of the pool (located on the beach), meant fabrication was largely done onsite.

“Because of the different shapes of the pool and the way we had to configure the posts for the fencing, we couldn’t manufacture panels in the workshop,” says Kevin.  “It would have been too disjointed so, instead, we rolled the shapes to the outline, cut them to length and then physically made it on site to ensure the most accurate fit.”

Some work had to be scheduled around tide times as the pool sits 10 feet from sea level with the fence right on the edge.  To get around this, Kevin said every second post was welded from the inside with the remaining posts completed on the outside.

To further help protect the job from tea staining, the welds were hand passivated with a gel and then coated with three different coatings from the Cyndan Rapelle range.  These coatings were “Stainless Steel Cleaner”, “Cleans All” and “Stainless Steel Sentry”.

Following installation, the Council was provided with a maintenance schedule, including recommendations for the use of these products.

This article featured in Australian Stainless Issue 40.

Subwharfyen Steels Your Imagination

A childhood spent yacht racing was Newcastle artist Braddon Snape’s inspiration for his intriguing new piece entitled The SubWharfyen at Darling Harbour.

“I was always surrounded by beautifully machined or crafted stainless steel rigging and equipment,” he said. So when Sydney Wharf commissioned Mr Snape to create a large-scale work depicting the relationship between people and the sea, stainless steel seemed like a natural choice.

Mr Snape’s experience in working with hardy materials and a highly evolved visual language proved a winning combination. The finished product is a great success as a premium contemporary development for the area.

Sydney Wharf recognised the potential for stainless steel to meet the requirements of the project for both aesthetics and durability.

“The use of stainless steel relates to its surroundings on both a conceptual and material level,” Sydney Wharf’s Shaun Farren said. “It has a connection with the maritime context and is durable in a marine environment.”

ASSDA Accredited Fabricator Marko Stainless provided their fabrication services for the project, using 450 kilograms of laser cut 3mm sheet in grade 316 stainless steel to produce The SubWharfyen from a one-in-twenty wooden model. Three panels comprise the body, which were rolled to form the curved sides. The panels were TIG welded, and blades MIG welded after initial polishing. All welds were pickled, and the entire sculpture passivated after completion.

On Mr Snape’s specification, a minimum 320 grit finish was used for its satin-like quality. “The finish allows the sculpture to respond to the light and colour of its surrounding environment without being consumed by busy reflections,” Mr Snape said.

Mr Snape describes the sculpture as “a synthesis of my aesthetic, poetic, intellectual and practical response to the particular site and the surrounding locale”.

This articled featured in Australian Stainless Issue 44.

Stainless Steel and Plumbing Standards

After three years of development, the first stage of a Standard covering the grade and dimensions of stainless steel pipes and tubes suitable for water supply and drainage systems has been completed. This interim Standard will be converted to a full Australian Standard in 2009.

The Standards Committee included ASSDA representative Neil McPherson of OneSteel, supported by the Technical Committee.

To avoid possible confusion and protect against corrosion problems in aggressive water supply areas, grades 316 and 316L are specified for the plumbing installation Code of Practice. All materials that satisfy the requirement for water supply and drainage systems must be included in the installation Standard AS/NZS 3500 Parts 1 & 2, which covers the material, grade and approved jointing method for piping systems.

If a material is included in Part 1 Water Supply (for drinking water), it will need to be certified against a product standard to Level 1, while Part 2 Drainage & Sanitary Plumbing requires Level 2 certification. The main difference is that Level 1 products require testing under AS4020 Material in Contact with Drinking Water to confirm lack of water contamination. Stainless steel product readily passes this testing.

All fittings, including the mechanical jointed pressfit and roll grooved types used for the plumbing services, are also tested and certified. AS3688 Metallic End Connectors defines the criteria against which these fittings are certified, including the additional pressure and fatigue testing to demonstrate strength of joint assembly.

Stainless steel using mechanical jointing systems

Mild steel, copper tube and plastic pipes have dominated building water systems for many years. However, high rise developments over recent decades have changed the building industry requirements for water supply and fire protection systems. These systems now require materials with a much higher pressure rating and corrosion resistance.

Stainless steel is recognised as a material most suited to meet these requirements. However, older on-site methods for jointing and fabrication has limited the use of stainless steel.

The approval of mechanical pressfit and roll grooved systems for all water systems has provided a major market for stainless. Stainless steel pipes and fittings have been installed as a solution to specific technical issues including a corrosive environment, high pressure requirements of the hydraulic services system, high operating temperature, or where the project owners are looking for a whole-of-life sustainable product solution.

The following projects illustrate some design and installation specifications around Australia.

Casey Aged Care Facility, Heidelberg, Victoria

108mm and 76mm tube in 316L was supplied by Blucher for a low pressure system feeding rainwater from storage tanks to pumps. Stainless steel was chosen due to concern of longevity and water contamination from other materials due to water levels in storage tanks being low or empty for long periods during dry spells. The Mapress stainless steel pressfitting system was familiar to the plumbing contractor who felt it was labour saving and easy to install. Plastic pipes were used from the roof to the plastic rainwater storage tanks.

Western Corridor Recycled Water Project, SE Queensland

The Mapress 316 pressure system was chosen for rapid, simple installation. There was a lack of pipe fitters available so socket welding was not possible and other trades made the installation. Sizes ranged from 15 to 54mm with butyl rubber sealing rings containing pressures up to 1,000kPa. The stainless steel was used for potable, treated and fire water as well as compressed air. The Mapress system supplied by Blucher has been used in all three waste water treatment plants in the Western Corridor as well as in the Gold Coast Desalination Plant.

Centre Court Business Park, North Ryde, NSW

Heating and chilled/condenser water installations used 316L schedule 5 pipe in both 50 and 100mm diameter in this 30,000m2 low rise complex. Stainless steel offered reliable protection from corrosion and the Victaulic roll grooved system offered ease of assembly.

Suncorp building, Sydney CBD

Refurbishment of the combined fire and drinking water system in a 1972 building used OneSteel Building Services supplied 316L schedule 10 pipe and fittings in 3m, pre grooved lengths for assembly in restricted duct spaces. The 43 floors plus 3 basements ensured high pressure requiring strong stainless steel which also met the drinking water AS4020 requirements.

Centrepoint Tower, Sydney CBD

Stainless steel pipe and fittings were supplied by OneSteel Building Services to replace corroded carbon steel in the 305m tall tower. Systems changed were the fire and potable water and the gas lines. 300m of 316L was supplied in 2.7m lengths which were roll grooved and assembled using Victaulic couplings in a very constricted service duct. Sizes used were 100mm and 50mm in schedule 10 except for gas lines in schedule 40.

This article featured in Australian Stainless magazine - Issue 45, Summer 2009.

Fishing for compliments: stainless steel fish art

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.


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.

Stainless integral to bridge's 300 year design life

Queensland’s largest ever road and bridge project will rely, in part, on innovation within the stainless steel industry to meet its design life of 300 years.

The Gateway Upgrade Project in Brisbane, which includes construction of a second Gateway Bridge and is being delivered by Queensland Motorways with design, construction and maintenance by the Leighton Abigroup Joint Venture (LAJV), will use reinforcement bar made for the first time from Outokumpu Group’s LDX 2101® duplex stainless steel.

A total of 130 tonnes of duplex stainless steel will be used in the bridge’s most critical structures: the splash zones of the two main river piers (28 tonnes of LDX 2101® have already been supplied and some Duplex 2205 will be used due to availability of dimensions for certain components).

Gateway Bridge Alliance Manager Gerry van der Wal said LDX2101® was chosen due to its high level of corrosion resistance (close to 316L) and low nickel content, which made it more cost effective and less susceptible to rapidly escalating worldwide nickel prices.

Outokumpu’s Qld and NT Manager Ken Hayes said that in bridge construction, stainless steel should be specified for parts where it makes a positive contribution, such as splash zones and the bridge deck.bridgepillar

“If carbon steel rebar is used, the bridge deck needs a water-proof membrane and the concrete must be of high quality, whereas if stainless rebar is used, reduced concrete cover can be specified, and it is also possible to relax the design criteria with respect to maximum crack width,” he said.

“As a result, with stainless rebar, bridges can be built either with no extra cost or for a lower cost than by using carbon steel reinforcement.”

Mr Hayes said LDX2101® offered the most cost-effective alternative for durable reinforced concrete structures and, due to its good price stability, it offered construction projects vitally important predictability.

“The win-win outcome from the use of LDX2101® is much improved sustainability in our constructed environment,” he said.

Because LDX2101® had never been used for rebar before this project, Outokumpu’s metallurgists carried out extensive tests to ensure it would withstand a high corrosion environment if the concrete were permeated by seawater.

A trial rebar coil was also sent to Atlas Specialty Metals’ Durinox facility in Melbourne to ensure it could be easily straightened.

Durinox Manager Colin McGill said they had to decoil the material, cut it to length and bend it to the appropriate shape.

“This was the first time we had processed the material and there were some challenges we had to overcome because of its very high strength,” Mr McGill said.

Once Outokumpu’s quality system and external testing criteria were approved by LAJV, the initial 28 tonnes of the hot rolled, ribbed, 16mm LDX2101® were delivered to Atlas Specialty Metals in Melbourne in 750kg coils for processing between October and December 2007.

The $1.88 billion Gateway Upgrade Project will be completed in 2011. It includes duplication of the original Gateway Bridge (which was completed in 1986), upgrade to 12km of the Gateway Motorway and construction of a new 7km deviation providing better access to Brisbane Airport.

Just over 20 years after it was constructed, the original Gateway Bridge is now exceeding capacity, carrying more than 100,000 vehicles each day.

When the duplication project is complete, the original bridge will carry six lanes of traffic north and the new bridge will carry six lanes of traffic south.

The new bridge is a 1.6km long balanced cantilever motorway bridge with the main span measuring 260 metres.

This article featured in Australian Stainless Issue 42 - Summer 2008.

Photos courtesy of Leighton Abigroup Joint Venture.

Mirror Mirror on the Water

Stainless Steel Fish Bar

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.

Mirror Mirror on the Lake

A new Stockland housing development on the Gold Coast has incorporated the use of art to promote outdoor living and community engagement. And, with a public lake the intended destination, artists Lubi Thomas and Adrian Davis knew stainless steel would best fit the bill.

The Highland Reserve development in Upper Coomera, 40 minutes south of Brisbane, boasts a mountainous backdrop and sprawling native bushland.  The additional inclusion of a lake within the development prompted Stocklands to commission a public artwork for the area.  Following a process of concept pitches from various artists, Lubi Thomas and Adrian Davis of Davis-Thomas were successful in securing the project.

“They (Stockland) have always, until now, bought artwork off the shelf,” Lubi Thomas says.  “This time though, they wanted to do something site-specific.”

After spending time in the area the artists discovered the most evident thing about the lake was its mirror-like quality.  They were inspired by the lake’s rippling responses to wind changes and wanted to convey this relationship to the general public.

The result was a series of nine stainless steel floating wind ‘petals’, each with their own anchor point and dispersed across the lake.  The use of mirrored stainless steel meant the original concept delivery was met.

“We needed to find a material that was robust enough, as well as something that would reflect the lake itself,” says Lubi. “That is what inevitably drew us towards mirrored stainless.”

The pieces are made entirely of grade 316 in sheet, tube and flat bar to cater to the environment, and to ensure a life of 20-25 years. The added benefit is that ongoing maintenance is limited to removing the marks of nature.

ASSDA member and Accredited Fabricator Rocklea Pressed Metal supplied materials for the works, and was further engaged for part of the fabrication.

Troy Olive of Rocklea Pressed Metal said the CAD drawings were sent to them, enabling them to laser cut and roll the petals to the desired radius.  In total, 12-15 sheets of stainless steel was used.

The use of mirrored stainless  meant an additional relationship was explored between the lake and the sun.  In the right conditions, the pieces react to the sunshine hitting the water, beaming light between the pieces.

This article featured in Australian Stainless magazine - Issue 40, Winter 2007.

Maintenance Critical to Stainless' Performance

The growth in the use of stainless steel over recent decades has been a real success story, predominantly due to its aesthetic appeal and, of course, its resistance to corrosion

 

However, the continuing performance of stainless steel, particularly in harsh coastal environments, relies not only on the intrinsic features of the material, but also on appropriate maintenance.

 

ASSDA Accredited Fabricator Bell Stainless from Kunda Park on the Sunshine Coast, Qld has had extraordinary success both nationally and internationally, being the only company in the world to have won multiple South Africa Stainless Steel Development Association Awards - one of only two Australian companies to win.

Bell Stainless general manager David Vine said they took the ongoing maintenance of their work very seriously and cited their installation several months ago of the balustrade for the HMAS Brisbane memorial at Alexandra Headland on the Sunshine Coast as a key example.

Mr Vine said they used two products from ASSDA member Cyndan Rapelle Pty Ltd - an Australian industrial chemical manufacturer - to keep this type of installation looking good:

- Cyndan Stainless Steel Cleaner, which uses a combination of phosphoric acid and ammonium biflouride, providing deep cleansing of grime, mineral salts, leaching, oxidation and other stains, particularly tea stains; and

- Cyndan Rapelle Stainless Steel Sentry - a protective treatment that fuses with the surface forming a water repellant film to reduce corrosive build up of salts.

He said they have used Cyndan products since 1999 and found them time effective, easy to manage and safe to use.

Cyndan Chemicals was founded in Australia in 1978 and has partnered with Rapelle Pty Ltd to market their products internationally.

This article featured in Australian Stainless magazine - Issue 37, Spring 2006.

Brisbane RiverWalk: Floating in Stainless

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.