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Chapter 5: Ferritic, Stainless Steel
Food Appliances and Nickel Problems
Without any problems, ferritic stainless steel may be used in most applications where the austenitic
steels are, at present, the state of the art. This includes the food industry, and the ferritic 4016 is
widely used for catering purposes in England and Italy, and the higher alloyed 4509, 4521 and 4526
may easily be used for more demanding purposes within the same business.
A particular advantage with the ferritic steel types is the absence of nickel and with a Ni content
of zero, the risk of Ni leaking into the media is equally zero. In contrast, the 4301 and 4404 contain
8 and 10 % Ni, respectively which (mostly by corrosion) may be leaked into the media. At present,
there are no rules and regulations with regard to the use of nickel free steel types in the food industry.
However, should this ever be the case, it does not hurt to be ahead of time.
Supply, Dimensions and Prices
The most important ferritic stainless steels are the 4509, the “acid resistant” 4521 and the very popular
4016. They are all available as sheets (various surfaces) and pipes; however, in all cases, the
thickness hardly ever exceeds 3 mm, apart from hot-rolled sheets. In any case, the supply time for
any ferritic stainless steel may be longer than for the similar austenites, and despite the increasing
production and demand, it will take a few years until the supply of the ferrites exceeds that of the
austenites.
The prices depend on the steel type, the dimensions, and, of course, the fluctuations in the alloy
surcharge. In particular, this is dependent on the nickel content, for which reason the economical
advantage of using the ferrites more or less follows the development in the nickel prices. The higher
the nickel price, the larger the economical advantage by switching to ferrites.
In July 2008, this difference was 25 %. However, the subsequent nickel drop has reduced this advantage.
Still, the price of the nickel-free ferrites is markedly more stable than for the austenites, and
in case of an exploding nickel price (once again!), the price difference is going to be much bigger.
Similar advantages are obtained for the acid resistant ferrite 4521 compared to the austenitic 4404.
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01.2013