What is 1.4401 Stainless Steel?
Apr 02, 2026
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1.4401 stainless steel, commonly known as 316 or UNS S31600, is a molybdenum-alloyed austenitic stainless steel that offers superior corrosion resistance compared to 304, particularly in chloride-containing environments. The addition of 2-3% molybdenum significantly enhances its resistance to pitting and crevice corrosion, making it the standard choice for applications where exposure to chlorides, industrial chemicals, or saline environments is expected. It is widely used in chemical processing, pharmaceutical equipment, marine applications, and food processing industries where higher corrosion resistance is required.
This molybdenum-enhanced grade is standardized across all major international systems.
| Standard | Equivalent Grade |
|---|---|
| EN (Europe) | 1.4401 |
| ASTM/AISI (USA) | 316, UNS S31600 |
| JIS (Japan) | SUS316 |
| KS (Korea) | STS316 |
| Common Name | 316 |
Molybdenum (Mo) is the key alloying element that differentiates it from 304 and provides enhanced corrosion resistance.
| Element | C | Si | Mn | P | S | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|
| Content (%) | ≤ 0.07 | ≤ 1.0 | ≤ 2.0 | ≤ 0.045 | ≤ 0.03 | 16.5 - 18.5 | 10.0 - 13.0 | 2.0 - 2.5 |
It offers good strength and excellent ductility, typical of austenitic stainless steels.
| Property | Yield Strength (Rp0.2) | Tensile Strength (Rm) | Elongation (A) | Hardness (HB) |
|---|---|---|---|---|
| Typical Value | ≥ 205 MPa | 500 - 700 MPa | ≥ 40% | ≤ 215 |
Key Characteristics and Applications of 1.4401 / 316
Superior Corrosion Resistance: The molybdenum content (2-2.5%) provides significantly better resistance to pitting and crevice corrosion in chloride-containing environments (e.g., seawater, de-icing salts, brine) compared to 304.
Good Acid Resistance: Offers improved resistance to a wide range of acids, including sulfuric, phosphoric, and acetic acids, making it suitable for chemical processing applications.
Excellent Formability and Weldability: Maintains the good forming and welding characteristics of austenitic stainless steels, though 316L is preferred for heavy welded sections.
Excellent Toughness: Maintains excellent impact resistance down to cryogenic temperatures, suitable for low-temperature applications.
Primary Applications:
Marine & Coastal: Boat fittings, underwater components, offshore platforms, and architectural cladding in salt-laden atmospheres.
Chemical Processing: Tanks, pipes, valves, pumps, and reactors for handling corrosive chemicals.
Pharmaceutical & Food: Equipment requiring high cleanliness, sterilization resistance, and resistance to cleaning agents.
Medical Devices: Surgical instruments and certain implant applications.
Architectural: High-end building facades, railings, and structural elements in corrosive environments.
Pulp & Paper: Process equipment in bleaching and chemical recovery areas.
Textile Industry: Dyeing and finishing equipment.
What is the primary advantage of 316 (1.4401) over 304 (1.4301) stainless steel?
The main advantage is the addition of 2-2.5% molybdenum, which dramatically improves resistance to localized corrosion-especially pitting and crevice corrosion-in environments containing chloride ions. This makes 316 the preferred choice for applications in marine environments, coastal areas, chemical processing plants using chlorides, and anywhere exposure to salt, brine, de-icing salts, or halogen compounds is expected. 316 also offers improved strength at elevated temperatures and better resistance to reducing acids. While 304 is suitable for general-purpose applications, 316 offers extended service life in more aggressive conditions.
Can 316 stainless steel be used in seawater applications?
While 316 is significantly more resistant to chloride attack than 304, its performance in stagnant or slow-moving seawater can be limited, especially at higher temperatures or in crevice conditions. For fully immersed seawater applications, more highly alloyed stainless steels (like duplex 2205, super duplex grades, or 6% Mo super austenitic grades) or non-ferrous alloys are often recommended. However, 316 is suitable for above-waterline marine components, splash zone applications, and in flowing seawater conditions with regular maintenance and cleaning. For applications requiring extended seawater immersion, higher alloyed materials should be considered.
What are the welding considerations for 316?
316 has good weldability using all common methods including TIG, MIG, SMAW, and SAW. Key considerations include:
Matching filler metals (ER316 for TIG/MIG, E316-16 for SMAW) are recommended
For heavy welded sections or applications requiring maximum corrosion resistance, 316L filler may be preferred
Low carbon versions (316L) eliminate sensitization risk without post-weld heat treatment
Recommended heat input: 0.5-2.0 kJ/mm
Interpass temperature should be kept below 150°C
Post-weld cleaning and pickling/passivation are recommended for optimum corrosion resistance
Looking for a Reliable Supplier of 1.4401 / 316 Stainless Steel?
GNEE Steel supplies premium 316 (1.4401) stainless steel in all standard forms-plate, sheet, coil, pipe, bar, wire, and fittings-tailored for corrosive environments. We provide full material certification (EN 10204 3.1) and comprehensive processing services including cutting, bending, forming, and surface finishing. If you have any requirements, please feel free to contact us.
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