ASTM 321H Stainless Steel

1. Core Chemical Composition (wt%)

Element	Content Range
Carbon (C)	0.04–0.10
Chromium (Cr)	17.00–19.00
Nickel (Ni)	9.00–13.00
Niobium + Tantalum (Nb+Ta)	10×C min – 1.00 max
Manganese (Mn)	≤2.00
Silicon (Si)	≤1.00
Phosphorus (P)	≤0.045
Sulfur (S)	≤0.030
Iron (Fe)	Balance

2. Key Performance Characteristics

Intergranular Corrosion Resistance: Niobium and tantalum preferentially react with carbon to form stable carbides. This prevents chromium carbide precipitation at grain boundaries during welding or high-temperature exposure, eliminating intergranular corrosion risks that affect unstabilized grades like 304.

High-Temperature Stability: It retains excellent strength and oxidation resistance at temperatures up to 900°C, which is higher than the service temperature limit of 321H. The high-carbon content further enhances its creep strength for long-term high-temperature applications.

Mechanical Properties (Room Temperature): Yield strength ≥205 MPa, tensile strength ≥515 MPa, elongation ≥40%. It has good ductility and formability, suitable for bending, stamping, and other fabrication processes.

Weldability: It can be welded using common methods such as TIG and MIG welding. No post-weld heat treatment is required, and the welded joint maintains consistent performance with the base metal.