AISI 316L Stainless Steel (UNS S31603): Marine-Grade Properties
ASTM A240/A276 · Published: 2026-05-27 · Updated: July 2026
AISI 316L (UNS S31603) is a low-carbon (≤0.03%) austenitic stainless steel with 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. The molybdenum addition provides superior resistance to pitting and crevice corrosion in chloride environments,...
AISI 316L (UNS S31603) is a low-carbon (≤0.03%) austenitic stainless steel with 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. The molybdenum addition provides superior resistance to pitting and crevice corrosion in chloride environments, making it the material of choice for marine, pharmaceutical, and chemical processing equipment. The 'L' designation prevents chromium carbide precipitation during welding, eliminating the need for post-weld annealing. Standard material for surgical implants, medical devices, offshore platforms, and coastal architecture.
Quick Facts
| Category | Stainless Steel |
| Standard | ASTM A240/A276 |
| Density | 8.00 g/cm³ |
| Yield Strength | 170 MPa (25 ksi) |
| Tensile Strength | 485 MPa (70 ksi) |
Physical Properties
| Melting Point | 1375-1400°C |
| Thermal Conductivity | 16.3 W/m·K at 20°C |
| Density | 8.0 g/cm³ |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN 1.4404 | Compare |
| X2CrNiMo17-12-2 | Compare |
| SUS316L | Compare |
| 022Cr17Ni12Mo2 | Compare |
| AISI 316L | Compare |
Heat Treatment & Processing
| Solution Annealing | 1040-1120°C, water quench |
| Stress Relieving | 250-425°C (avoid 425-860°C) |
| Note | Cannot be hardened by heat treatment |
Welding & Fabrication
| Preheat | Not required |
| Filler Metal | ER316L (GMAW), E316L-16 (SMAW) |
| Interpass Temp | Max 175°C |
| Weldability Rating | Excellent |
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Frequently Asked Questions
Why choose 316L over 304?
316L adds 2-3% molybdenum for dramatically improved pitting resistance in chloride environments. For coastal/marine, chemical processing, or any salt exposure, 316L is the minimum recommended grade. It also has the low-carbon advantage for as-welded fabrication. 316L is approximately 25-40% more expensive than 304.
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