The 321 stainless steel is mainly 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 titanium addition of 5 times the carbon content. This titanium addition reduces or prevents carbide precipitation during welding and in the 800°-1500°F service conditions. For providing 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.
Stainless Steel 321 Chemical Composition, %
The chemical composition of stainless steel 321 is:
| 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 | Balance |
Forms of 321 Stainless Steel
321 Stainless Steel is available in the following forms at wilsonpipeline Pipe Industry Co., Limited:
- Plate
- 321 Stainless Steel Seamless and Welded Pipe Bend
- Bar
- 321 Stainless Steel Pipe & 321 Stainless Steel U Tube .
- Fittings (i.e., flanges, slip-ons, blinds, weld-necks, lap joints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)
- Weld Wire.
Features of Stainless Steel 321
The features of stainless steel 321 are:
- Oxidation resistant to 1600°F.
- Stabilized against weld heat affected zone (HAZ) intergranular corrosion.
- Resists polythionic acid stress corrosion cracking.
Mechanical Properties (Average Elevated Temperature Tensile Properties)
The mechanical properties of stainless steel 321 are:
| 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 |
Welding Stainless Steel 321
321 Stainless Steel is 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 normally 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.
Applications
The applications of stainless steel 321 are:
- Expansion joints
- Thermal oxidizers
- Refinery equipment
- Aircraft piston engine manifolds and exhaust stacks
- High temperature chemical process equipment.
This information has been sourced, reviewed and adapted from materials provided by wilsonpipeline Pipe Industry Co., Limited.
For more information on this source, please visit wilsonpipeline Pipe Industry Co., Limited.
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