Stainless steel (321) has an excellent Stress Rupture property and Creep Resistance Stress of high temperature, and its mechanical properties are higher than 304 stainless steel.
321 Chemical Composition:
Austenitic stainless steel is equivalent to GB standard 0Cr18Ni10Ti, 321 stainless steel is ni-cr-mo austenitic stainless steel, its performance is very similar to 304, but due to the addition of titanium metal, it has better grain boundary corrosion resistance and high temperature strength. Due to the addition of titanium, the formation of chromium carbide is effectively controlled.
321 austenitic stainless steel has good corrosion resistance in the atmosphere and is widely used in petrochemical industry, electric power, bridge and automobile industries.
But the stainless steel is not absolute "stainless", because of the special service environment, stainless steel will corrosion. Medium concentration, pH value, temperature and other factors will have a greater impact on the corrosion resistance of stainless steel.
For example, in the range of 450~850℃ sensitization temperature long-term use, stainless steel will occur intercrystalline corrosion. The mechanism is that C combines with Cr at the grain boundary to form Cr23C6 and precipitate out, reducing the Cr content at the grain boundary. This is the so-called "poor chromium".Cr element is one of the main elements inhibiting intercrystalline corrosion. When the Cr content at the grain boundary is less than 12%, the probability of intercrystalline corrosion will increase.
It is used in outdoor machines with high chemical, coal and petroleum industries to resist grain boundary corrosion
1. Petroleum exhaust combustion pipeline
2. Engine exhaust pipe
3. Boiler shell, heat exchanger, heater parts
4. Silencing components for diesel engines
5. Boiler pressure vessel
6. Chemical tanker
7. Expansion joint
8. Spiral welded pipes for furnace pipes and dryers