Description

321 austenitic stainless steel has good corrosion resistance in the atmosphere and is widely used in petrochemical, power, bridge and automotive industries.
However, the “rusting” of stainless steel is not absolute. Due to the special use environment, stainless steel can also corrode.
Media concentration, pH, temperature and other factors will have a greater impact on the corrosion resistance of stainless steel.
For example, in the 450 ~ 850 ℃ sensitization temperature range for long-term use, stainless steel will occur intergranular corrosion.
The mechanism is the combination of C and Cr in the grain boundary to form Cr23C6 and precipitate out, so that the Cr content of the grain boundary is reduced, the so-called “poor chromium”.
Chromium is one of the main elements that inhibit intergranular corrosion. When the Cr content at the grain boundaries is below 12%, the probability of intergranular corrosion increases.