Alloy 321/321H ( UNS S32109) Pipe & Fittings
Alloy 321/321H is austenitic stainless steel that contains stabilizing elements. It is easily welded. Annealing is often not required after welding unless stress relief is desired. It has excellent resistance to oxidation and corrosion. The addition of titanium in Alloy 321H stainless steel gives some desired characteristics:
- Prevents harmful carbide precipitation in the heat-affected zone (HAZ) of the weld area
- Imparts partial immunity to intergranular corrosion
- Reduced embrittlement in the HAZ of the weld area
Alloy 321H stainless steel is a widely used stainless steel, where parts are heated within the carbide-precipitation temperature range (800°F-1500°F) and exposed to a corrosive atmosphere. Alloy 321H stainless steel is similar to 304 stainless steel but with higher nickel content and stabilized with titanium. Titanium preferentially reacts with carbon in the steel and prevents precipitation of chromium carbides at the grain boundaries, thus preserving corrosion-resistant properties by preventing depletion of chromium near the grain boundaries during exposure within a critical temperature range. This grade responds well to hardening by cold working. It has good welding characteristics, and post-weld annealing is not normally required to restore its excellent performance in a wide range of corrosive conditions.
- Responds well to hardening by cold working
- Good welding characteristics
- Excellent corrosion resistance in a wide variety of corrosive media
- High creep & stress rupture properties
