What is Stainless Steel SUS321？

The characteristics of SUS321 stainless steel are the properties that make it suitable for various applications and environments. Some of the main characteristics of SUS321 stainless steel are:

Excellent resistance to intergranular corrosion in the chromium carbide precipitation range (800-1500°F, 427-815°C) . This means that SUS321 stainless steel can withstand exposure to high temperatures without losing its corrosion resistance due to the formation of chromium carbide at the grain boundaries, which can cause cracking and failure. This is achieved by the addition of titanium, which stabilizes the carbon and prevents it from reacting with chromium .

Good resistance to oxidation and general corrosion in various environments . This means that SUS321 stainless steel can resist the attack of oxygen and other corrosive agents in different media, such as air, water, acids, alkalis, salts, etc. This is due to the high chromium and nickel content, which form a protective oxide layer on the surface of the steel .

Good resistance to stress corrosion cracking and pitting corrosion . This means that SUS321 stainless steel can resist cracking and pitting caused by tensile stress and chloride ions in corrosive environments, such as seawater, salt spray, etc. This is due to the high nickel content, which enhances the resistance to chloride stress corrosion cracking .

Good weldability and formability . This means that SUS321 stainless steel can be easily welded and processed by standard shop fabrication practices, such as forging, rolling, extrusion, drawing, bending, forming, etc. It does not require post-weld annealing to restore its corrosion resistance, but it is recommended to use low carbon filler metal such as ER347 or ER316L to avoid intergranular corrosion . It also has good ductility and can be formed with ease .

Good creep and stress rupture properties at high temperatures . This means that SUS321 stainless steel can maintain its strength and durability under prolonged exposure to high temperatures and pressures. It has higher creep and stress rupture properties than alloys 304 and 304L, which are commonly used austenitic stainless steels 14. This is due to the addition of titanium, which enhances the creep resistance by forming stable titanium carbides in the steel matrix .

Non-magnetic and heat resistant . This means that SUS321 stainless steel does not exhibit magnetic properties when subjected to a magnetic field. It also resists oxidation up to 1500°F (816°C), which is higher than most austenitic stainless steels . This is due to the high chromium content, which forms a protective oxide layer on the surface of the steel.

These characteristics make SUS321 stainless steel a versatile and durable material for various applications that require high performance and reliability at high temperatures.