The magic of a clear night sky filled with stars has inspired many creative souls. Now, through a collaboration between science and art, a stainless steel sculpture installed at the Australian National University in Canberra brings new depth to the connection between ourselves and the stars above.
The normal state for stainless
Stainless steels resist corrosion because they have a self-repairing “passive” oxide film on the surface. As long as there is sufficient oxygen to maintain this film and provided that the level of corrosives is below the steel’s capacity of the particular material to repair itself, no corrosion occurs. If there is too high a level of (say) chlorides, pitting occurs. As an example, 316 works well in tap water (<250 ppm) all over Australia, but will rapidly corrode in seawater because seawater has very high chloride levels (20,000 ppm).
ASSDA member Australian Pickling & Passivation Service (APAPS) and ASSDA sponsor Sandvik Mining & Construction have been central to the expansion of a coal export port in North Queensland.
In the beleaguered Australian manufacturing sector, it's heartening to find ASSDA member Tasman Sinkware is a world-class leader in innovative design and manufacturing. Better still, in addition to supplying the domestic market, Tasman is exporting its products to Canada, the United States, New Zealand, Hong Kong and Singapore.
Almost all of the stainless steels in use have 16% chromium or more and have nickel or other additions to make them austenitic and hence formable, tough and readily weldable. However, the formal definition of a stainless steel is that it is an iron- and carbon-based alloy with more than 10.5% chromium. Historically, the corrosion mitigation industry regarded alloys with more than 12% chromium as stainless steels mainly because those alloys did not corrode in mild environments. Because of the perceived problem of high initial price when using stainless steels, alloys that are ‘barely’ stainless (and with low nickel to boot) are more competitive with painted or galvanised carbon steel than higher alloys.
This is an abridged version of a story that first appeared under the same title in Stainless Steel Focus No. 07/2012.
The Nickel Institute's director of promotion, Peter Cutler, and consultant Gary Coates, reveal some of the reasons for the continuing popularity of nickel in stainless steels.
Stainless steel is everywhere in our world and contributes to all aspects of our lives. We find stainless steel in our homes, in our buildings and offices, in the vehicles we travel in and in every imaginable industrial sector. Yet the first patents for stainless steel were issued only 100 years ago.
How did this metal become so desirable over the past century that more than 32 million tonnes was produced in 2011? And how does nickel, a vital alloying element in most stainless steel alloys, contribute to the high demand for stainless steel?