904L
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Special Steels Division
Wire Division
904L - High-Alloy Stainless Steel
904L is a high-alloy austenitic stainless steel that is specifically designed for environments where high resistance to corrosion is essential. It contains significant amounts of nickel, chromium, molybdenum, and copper, giving it outstanding resistance to a wide range of aggressive corrosive media, including sulfuric acid, phosphoric acid, and seawater. 904L is commonly used in industries such as chemical processing, oil and gas, pharmaceuticals, and marine applications due to its durability and resistance to corrosion, stress corrosion cracking, and pitting.
The alloy’s high nickel content provides excellent resistance to oxidation and its molybdenum content improves its resistance to pitting and crevice corrosion, making it one of the best materials for environments that involve harsh chemicals or saline solutions.
Features of 904L:
- Excellent Corrosion Resistance: Superior resistance to corrosion in aggressive environments, including sulfuric and phosphoric acids, and chloride-induced corrosion.
- Good Weldability: 904L has excellent weldability using common welding techniques such as TIG, MIG, and SMAW welding, ensuring it is suitable for a wide range of fabrication processes.
- High Strength: It offers good mechanical properties at both room temperature and elevated temperatures, including excellent tensile strength and resistance to fatigue.
- Resistance to Stress Corrosion Cracking: The high nickel content gives it excellent resistance to stress corrosion cracking, especially in chloride environments.
- Pitting and Crevice Corrosion Resistance: The alloy is highly resistant to pitting and crevice corrosion in aggressive environments, including in seawater and chlorides.
- Non-Magnetic: Like many austenitic stainless steels, 904L is non-magnetic in the annealed condition.
- Formability: 904L is highly formable and can be easily fabricated into a variety of shapes and sizes.
Specifications:
- ASTM A240 (Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications)
- ASTM A312 (Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes)
- UNS N08904
- ASME SA240
- EN 1.4539
Composition of 904L:
Element | Percentage |
---|---|
Nickel (Ni) | 23.0-28.0% |
Chromium (Cr) | 19.0-23.0% |
Molybdenum (Mo) | 4.0-5.0% |
Copper (Cu) | 1.0-2.0% |
Iron (Fe) | Balance |
Carbon (C) | 0.02% Max |
Manganese (Mn) | 2.0% Max |
Silicon (Si) | 1.0% Max |
Sulfur (S) | 0.03% Max |
Phosphorus (P) | 0.045% Max |
Physical Properties:
Property | Value |
---|---|
Density | 8.0 g/cm³ |
Melting Point | 1375-1400°C (2500-2550°F) |
Hardness (BHN) | 190-220 BHN |
Tensile Strength | 520 MPa (75,000 psi) |
Yield Strength | 220 MPa (31,000 psi) |
Elongation | 40% |
Modulus of Elasticity | 200 GPa |
Thermal Conductivity | 14.9 W/m·K |
Coefficient of Thermal Expansion | 16.5 x 10^-6 /°C |