Delivery date, method and place 2. Does stainless steel never rust?
The different characteristics of stainless steel are attributed to the
different elements added along with ferrum element. Stainless steel is
anti-rust because the chromium (CR) element added can form a
dense oxide film. However, once stainless steel is exposed to high
temperature or a strong chemical environment for a long time, the
oxide film on the surface will be destroyed and lead to corrosion. 3. Into what categories is stainless steel usually divided according to matrix structure?
Usually stainless steel can be divided into following categories by
1. Ferritic stainless steel, which contains 12% ~ 30% Cr. Its corrosion
resistance, toughness and weldability is improved with the increase
of Cr content, and its resistance against chloride stress corrosion is
superior to other types of stainless steel.
2. Austenitic stainless steel, which contain over 18% Cr, about 8% Ni
and a small amount of Mo, Ti, N and etc. It has good overall perfor
mance and is resistant to a variety of chemical medium corrosion.
3. Austenitic-ferritic duplex stainless steel, which has the merits of both
austenitic and ferritic stainless steel. It has an excellent performance
in superplasticity as well.
4. Martensitic stainless steel, which is of high strength but bad in plasticity
According to chemical composition, it can be divided into CR series
(SUS400), CR-NI series (SUS300), CR-MN-NI(SUS200) and precipitation
hardening series (SUS600).
200 series - Cr - Ni - Mn austenitic stainless steel
300 series - Cr - Ni austenitic stainless steel
400 series - ferritic and martensitic stainless steel
500 series - heat resistant chromium alloy steel
600 series - martensitic precipitation hardening stainless steel