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Stainless 321 is a heat resistant, titanium stabilized, austenitic alloy that's commonly used for service in the 1000°-1600°F temperature range. 321 stainless is primarily used in applications that involve continuous and intermittent service temperatures within the carbide precipitation range of 800°-1500°F. Type 321 is similar to type 304 stainless but with a titanium addition of at least five times the carbon content. This titanium addition reduces or prevents carbide precipitation during welding and in the 800°-1500°F service conditions. In order to provide optimum resistance to intergranular corrosion and to polythionic acid stress corrosion cracking in service temperatures at 1500°-1650°F an air cool may be used.
Cr | Ni | Mo | Cu | Ti | C | |
---|---|---|---|---|---|---|
MIN | 17.0 | 9.0 | - | - | 5x(C+N) | - |
MAX | 19.0 | 12.0 | 0.75 | 0.75 | 0.70 | 0.08 |
Mn | Si | P | S | N | Fe | |
MIN | - | 0.25 | - | - | - | - |
MAX | 2.0 | 1.0 | 0.04 | 0.03 | 0.1 | Bal |
Oxidation resistant to 1600°F
Stabilized against weld heat affected zone (HAZ) intergranular corrosion
Resists polythionic acid stress corrosion cracking
Aircraft piston engine manifolds and exhaust stacks
Expansion joints
Thermal oxidizers
Refinery equipment
High temperature chemical process equipment
Average Elevated Temperature Tensile Properties
Temperature, °F | Ultimate Tensile Strength, ksi | .2% Yield Strength, ksi |
---|---|---|
68 | 84 | 38 |
400 | 62 | 20.5 |
600 | 62 | 18 |
800 | 62 | 17 |
1000 | 59.5 | 16.5 |
1200 | 45.5 | 16 |
1400 | 27.5 | 14 |
321 Stainless is readily welded by all common methods including submerged arc. Appropriate weld fillers are most often specified as AWS E/ER 347 or E/ER 321. This alloy is generally considered to have comparable weldability to 304 and 304L stainless with the main difference being the titanium addition which reduces or prevents carbide precipitation during welding.