Nickel prices have been relatively high over the last couple of years. As a result, there has been increased interest in low-nickel or no-nickel grades of stainless steel.
One such family of stainless steels is the 200-series and use of these has doubled this decade. They have become popular in China and South East Asia, particularly. However, this has not been without problems.
Because the 200-series grades are austenitic, they are not magnetic and are therefore difficult to distinguish from the widely used 300-series grades, such as 304 or 316, which are also non-magnetic.
This has led to confusion in the marketplace, including cases of incorrect labelling, etc, with 200-series material being sold as 304.
Most growth in 200-series use over recent years has been in low-nickel and therefore low-chromium versions that have less corrosion resistance than 304.
The end result has been corrosion failures in some applications and dissatisfied customers. In addition, there are concerns that this 200-series material may contaminate the existing stainless steel recycling circuit, which is based on 304.
The 200-series is a technically valid family of stainless steels but, like all stainless steel grades, they have their limitations.
If you are considering the use of a 200-series material then you should ensure you have all the necessary data you require to make a rational judgment – mechanical and physical properties, corrosion performance in your environment, etc.
And it is strongly recommended that you deal only with reputable and knowledgeable suppliers who can provide high quality material of known origin.
Information about stainless steel is available from contact Australian Stainless Steel Development Association.