The main justification for selecting Stainless Steel for a given application is its outstanding corrosion and oxidation resistance. They equally possess other exceptional properties, such as the ability to develop very high strength through cold working or heat treatment, excellent formability and the capability to withstand cryogenic temperatures, makes it a very versatile material.
Stainless steels have a wide range of microstructures which are controlled by composition. However, all Stainless Steels must contain chromium to form the complex oxide surface which gives Stainless Steel its protective corrosion resistance. Other alloying elements have significant effects to the mechanical properties of the material. As Stainless Steels is such a large group, with many variations in characteristics and composition, it is often more beneficial to categorise them in terms of microstructure. Commercial forms of Stainless steel fall into the following categories:
Material | Grades Supplied | Main features | Advantages | Disadvantages |
Austenitic Steel with Manganese | 201 |
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Austenitics | 301, 304L, 304, 305, 320, 321, 347, | |||
Austenitic Steel with Molybdenum | 316, 316L, 316Ti, 904L | |||
Ferritics | 409, 410S, 430, 430L, 430Ti (439), 441, 444 |
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Martensitics | 410, 420, 431 |
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Precipitation hardening | 17/4PH, 17/7PH |
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Duplex | 309, 310 |
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* cold working of the less alloyed grades will induce structural changes leading to increased levels of magnetism. **Super Austenitics, Super Ferritic and Super Duplexes are available by request |