Stainless steels are a family of steels which include at least 11% chrome in their compounds. The fundamental fact that enables these steels resist against corrosion is the presence of a layer of oxide which is strictly attached to this surface, is dense , very thin and transparent. By means of this very thin layer, stainless steels gain resistance against corrosion by remainig in passive mode in chemical reactions. This layer of oxide occurs in environments where oxygen exists and regains its former feature by restoring itself even if it deteriorates due to outer factors( cutting, abrasion, etc.)
Basically stainless steels are grouped under 5 main topics ;
- Ferritic,
- Martenzitik,
- Ostenitic,
- Ferritic- Ostenitic (Dublex),
- Alloy suitables for applying precipitation stiffening.
of all these groups, the most widely used ones are ferritic and ostenitic steels. Ferritic stainless steels include low carbon and 12-18 % chrome while ostenitic stainless steels include 18% chrome and 8% nickel. Ferritic stainless steels can be magnetized as thet don’t include nickel in their alloys. If the whole stainless steel production is researched, it can be seen that ostenitic stainless steels are on the top of the list with a production rate of 70%.
Source : http://www.elbirmetal.com
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