TYPES OF STAINLESS STEEL
Stainless steels are steel alloys containing chromium; their chromium content varies from 12 to 30% and they may contain nickel up to 24%, and some other elements as molybdenum, silicon, copper, titanium, niobium, nitrogen etc up to a few percent. Chromium has a crucial role to play at alloy building since chromium gives the alloy its ability to resist environmental influences.
In certain environments, steel tends to corrode in a certain way (spot corrosion, crevice corrosion, grain-boundary corrosion, corrosion cranks). This, however, can be avoided if steel is chosen to suit the environment to which it will be subjected. Various alloy elements like chromium, nickel and manganese are present only to a smaller degree; therefore, the definitive factor is the alloy of iron and carbon, which is the steel.
Stainless steels are classified by their chemical composition and crystalline structure:
- austenitic,
- ferritic
- martensitic (suitable for quenching)
- austenitic-ferritic (duplex stainless steel)