AISI 321 Stainless Steel: Titanium-Stabilized for High-Temp Service
ASTM A240/A276 · Published: 2026-05-29 · Updated: July 2026
AISI 321 is an austenitic stainless steel stabilized with titanium (5× carbon content minimum), which preferentially forms titanium carbides instead of chromium carbides during welding or elevated-temperature service. This prevents sensitization...
AISI 321 is an austenitic stainless steel stabilized with titanium (5× carbon content minimum), which preferentially forms titanium carbides instead of chromium carbides during welding or elevated-temperature service. This prevents sensitization and intergranular corrosion without the need for post-weld solution annealing. Used extensively for aircraft exhaust systems, furnace components, expansion joints, and high-temperature chemical processing equipment. Service temperatures up to 815°C (1500°F) in oxidizing atmospheres. Titanium stabilization also improves creep strength compared to 304.
Quick Facts
| Category | Stainless Steel |
| Standard | ASTM A240/A276 |
| Density | 8.00 g/cm³ |
| Yield Strength | 205 MPa (30 ksi) |
| Tensile Strength | 515 MPa (75 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN 1.4541 | Compare |
| X6CrNiTi18-10 | Compare |
| SUS321 | Compare |
| 06Cr18Ni11Ti | Compare |
| AISI 321 | Compare |
Related Materials
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Frequently Asked Questions
When should 321 be specified instead of 304L?
Use 321 when the component operates continuously above 425°C (800°F) where 304L will sensitize over time despite low carbon. 321 also offers better creep resistance and high-temperature strength. For ambient-temperature welded structures, 304L is more economical and achieves the same sensitization resistance through low carbon content. 321 is preferred in aerospace exhaust systems and refinery heater tubes.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu