Alloy 321 (UNS S32100) is a titanium stabilized austenitic stainless steel plate with good corrosion resistance. It has great resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range of 800 – 1500°F (427 – 816°C). The alloy is resistance to oxidation up to 1500°F (816°C) and possesses higher creep and stress rupture properties than alloys 304 and 304L. It also has good low temperature toughness.
Alloy 321H (UNS S 32109) stainless steel plate is the higher carbon (0.04 – 0.10) version of the alloy. It was designed for enhanced creep resistance and for higher strength at temperatures above 1000oF (537°C). In most cases, the carbon content of the plate permits dual certification.
Slightly tougher than 304 stainless, this material will produce the same tough stringy chips. The usage of slow speeds and constant positive feeds will minimize this alloy’s tendency to work harden. 321 can be welded by all commonly used fusion and resistance methods. Oxyacetylene welding is not recommended. When needed, use AWS E/ER347 filler metal. Working temperatures of 2100-2300 F (1149-1260 oC) are recommended for forging, upsetting and other hot work processes. Do not work this alloy at temperatures below 1700 oF (927 oC). Material must be water quenched or fully annealed after working to maintain maximum corrosion resistance. Although this material needs higher initial forces than 304 stainless, it is rather tough and ductile and can be readily stamped, blanked, spun and drawn.