Alloy 321 (UNS S32100)
Alloy 321 is a titanium-stabilised austenitic stainless steel designed to prevent chromium carbide precipitation during welding and high-temperature exposure. The addition of titanium provides improved resistance to intergranular corrosion compared with unstabilised grades such as 304.
This alloy retains excellent mechanical strength and oxidation resistance at elevated temperatures and offers good creep resistance. Alloy 321 is widely used in high-temperature service applications such as exhaust systems, heat exchangers, and pressure vessels where prolonged exposure to elevated temperatures is required.
Specifications
- UNS: S32100
- ASTM: A276, A182 F321, A240
- EN / DIN: 1.4541
- Structure: Austenitic (Titanium Stabilised)
- Condition Supplied: Annealed
Data Tables
Chemical Composition:
| C | Mn | P | S | Si | Cr | Ni | Ti | Mo | N | Cu | Fe | Co | Nb (+Ta) | V | W | Al | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | 17 | 9 | 5 x C | ||||||||||||||
| Max | 0.08 | 2 | 0.045 | 0.03 | 1 | 19 | 12 | 0.7 | 0.1 | Bal |
Mechanical Properties:
| Material Grade | ASTM Standard | Desgnation(EN /UNS) | Yield Strength (MPa) | Yield Strength (KSI) | Tensile Strength (MPa) | Tensile Strength (KSI) | Elongation (%) | Reduction of Area (%) | Hardness(HRC/HBWMax) | Condition | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| SS 321 | ASTM A276 / A182 / A479 | EN 1.4541(S32100) | 205 | 29.73279 | 515 | 74.69457 | 30 | 50 | 215 HBW | Solution Annealed |
Physical Properties:
| Material Grade | Density (g/cm³) | Melting Range (°C) | Modulus of Elasticity (GPa) | Thermal Conductivity (W/m·K) | Thermal Expansion (×10⁻⁶ /°C) | Electrical Resistivity (µΩ·m) | Magnetic Behavior |
|---|---|---|---|---|---|---|---|
| 321 | 7.9 | 1400–1420 | 193 | 16 | 16 | 0.72 | Non-magnetic |
Key Features
- Titanium stabilised to prevent carbide precipitation
- Excellent resistance to intergranular corrosion at high temperature
- Good creep and stress rupture strength
- Suitable for prolonged elevated temperature service
- Good weldability
Applications
- Aircraft exhaust systems
- Heat exchangers
- Furnace components
- Expansion joints
- High-temperature pressure vessels