Stainless Steel 321 / 321H Pipe
Titanium Stabilized High-Temperature Stainless Steel Pipes
SS 321 Pipe is an austenitic stainless steel similar to 304 but stabilized with Titanium. The titanium addition effectively eliminates intergranular corrosion and carbide precipitation that can occur during welding or exposure to high temperatures (427°C - 816°C). Grade 321H is the higher carbon version designed for improved high-temperature strength, commonly used in aerospace and heavy chemical processing.
Technical Specifications
| Feature | Details |
|---|---|
| Standards | ASTM A312, A358, A213, A269 |
| Grades | TP 321, TP 321H |
| Size Range | 1/2" NB to 24" NB (Seamless), up to 48" (Welded) |
| Schedule | SCH 10S, 40S, 80S, 160, XXS |
| Manufacturing | Seamless / ERW / Welded / Cold Drawn |
| Finish | Pickled, Polished, Bright Annealed |
Mechanical Properties
| Property | Grade 321 | Grade 321H |
|---|---|---|
| Yield Strength (0.2% Offset) | Min 205 MPa | Min 205 MPa |
| Tensile Strength (Min) | 515 MPa | 515 MPa |
| Elongation (Min %) | 35 - 40% | 35 - 40% |
| Hardness (Brinell) | Max 217 HBW | Max 217 HBW |
Chemical Composition (%)
| Element | SS 321 | SS 321H |
|---|---|---|
| Carbon (C) | 0.08 max | 0.04 - 0.10 |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Chromium (Cr) | 17.0 - 19.0 | 17.0 - 19.0 |
| Nickel (Ni) | 9.0 - 12.0 | 9.0 - 12.0 |
| Silicon (Si) | 0.75 max | 0.75 max |
| Phosphorus (P) | 0.045 max | 0.045 max |
| Sulfur (S) | 0.030 max | 0.030 max |
| Nitrogen (N) | 0.10 max | 0.10 max |
| Titanium (Ti) | 5x(C+N) min - 0.70 max | 4x(C+N) min - 0.70 max |
Features and Benefits of SS 321 Pipe
- Immune to intergranular corrosion when heated within the carbide precipitation range
- Titanium stabilization prevents sensitization during long-term exposure to heat
- 321H provides superior creep-rupture strength for high-temperature service
- Excellent mechanical properties with high toughness and stability
- Highly resistant to oxidation in service temperatures up to 815°C
- Superior weldability compared to Grade 304 in heavy gauge sections
- Widely used in environments containing corrosive exhaust gases
- Non-magnetic behavior similar to other austenitic grades
Applications & Uses
Aerospace
Used in aircraft exhaust stacks, manifold systems, and jet engine components.
Thermal Units
Ideal for boiler tubes, heat exchanger tubing, and expansion joints in power plants.
Refineries
Applied in high-temperature chemical processing and refining exhaust equipment.