321 and 321H stainless steels are basic types of austenitic stainless steels, which are stabilized by the addition of Titanium. This stabilization helps to prevent carbide precipitation during welding and exposure to high temperatures.
- 321 Stainless Steel: It has a good corrosion resistance similar to 304 stainless steel, but with added resistance to intergranular corrosion following welding or stress relieving. It’s designed to resist oxidation and scaling at temperatures up to 900°C. It’s often used in applications involving continuous or intermittent service at temperatures up to 900°C, like aircraft exhaust manifolds and expansion joints.
- 321H Stainless Steel: The “H” in 321H stands for High Carbon and this grade is used for high temperature applications. It has a higher carbon content compared to 321, typically around 0.04-0.10%. The increased carbon content allows it to withstand high temperatures, making it ideal for applications that require strong heat resistance, such as power generation and petrochemical environments.