AISI 304 Stainless Steel (UNS S30400): Properties & Equivalents
ASTM A240/A276 · Published: 2026-05-26 · Updated: July 2026
AISI 304 (UNS S30400) is the most common austenitic stainless steel, containing 18-20% chromium and 8-10.5% nickel. This classic '18/8' composition provides excellent corrosion resistance in atmospheric, food-processing, and mild chemical...
AISI 304 (UNS S30400) is the most common austenitic stainless steel, containing 18-20% chromium and 8-10.5% nickel. This classic '18/8' composition provides excellent corrosion resistance in atmospheric, food-processing, and mild chemical environments, coupled with good formability and weldability. 304 cannot be hardened by heat treatment but work-hardens rapidly during cold forming. It is non-magnetic in the annealed condition but may become slightly magnetic after cold working. Applications span from kitchen equipment and food processing machinery to architectural trim and chemical containers.
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) |
Physical Properties
| Melting Point | 1400-1450°C |
| Thermal Conductivity | 16.2 W/m·K at 20°C |
| Density | 8.0 g/cm³ |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN 1.4301 | Compare |
| X5CrNi18-10 | Compare |
| SUS304 | Compare |
| 06Cr19Ni10 | Compare |
| AISI 304 | Compare |
Heat Treatment & Processing
| Solution Annealing | 1010-1120°C, rapid quench |
| Stress Relieving | 250-425°C (avoid 425-860°C) |
| Note | Cannot be hardened by heat treatment |
Welding & Fabrication
| Preheat | Not required |
| Filler Metal | ER308L (GMAW), E308L-16 (SMAW) |
| Interpass Temp | Max 175°C |
| Weldability Rating | Excellent |
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Frequently Asked Questions
Is 304 stainless steel magnetic?
In the annealed condition, 304 is essentially non-magnetic. However, cold working causes partial transformation of austenite to martensite, making cold-worked areas slightly magnetic. This is normal and does not affect corrosion resistance. For truly non-magnetic applications, consider 316L or specialized high-nickel alloys.
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