Alloy F51
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Alloy F51 (UNS S31803) - Duplex Stainless Steel
Alloy F51, also known as UNS S31803, is a duplex stainless steel designed to offer a balance of high strength and excellent corrosion resistance, particularly in chloride-containing environments. With a microstructure that consists of approximately equal parts of ferrite and austenite, it provides superior stress corrosion cracking (SCC) resistance and better mechanical properties compared to austenitic stainless steels.
Features of Alloy F51:
- High Corrosion Resistance: Excellent resistance to pitting, crevice, and general corrosion in chloride-rich environments.
- Stress Corrosion Cracking Resistance: Strong resistance to stress corrosion cracking in marine and other chloride-containing environments.
- Superior Strength: Higher yield strength than austenitic grades such as 304 and 316.
- Good Weldability: Can be welded using standard welding methods, typically without the need for post-weld heat treatment.
- Improved Mechanical Properties: Good toughness at low temperatures and excellent fatigue strength.
Specifications:
Applicable Standards:
- ASTM A240, ASTM A276, ASTM A479, ASTM A790, UNS S31803
Mechanical Properties:
Property | Value |
---|---|
Tensile Strength | ~700 MPa |
Yield Strength | ~450 MPa |
Elongation | ~25% |
Hardness (BHN) | ~290 |
Density | 7.8 g/cm³ |
Thermal Properties:
- Melting Range: 1350-1400°C
Chemical Composition:
Element | Percentage (%) |
---|---|
Chromium (Cr) | 22.0-23.0 |
Nickel (Ni) | 4.5-6.5 |
Molybdenum (Mo) | 2.5-3.5 |
Nitrogen (N) | 0.08-0.20 |
Carbon (C) | ≤0.03 |
Silicon (Si) | ≤1.0 |
Manganese (Mn) | ≤2.0 |
Phosphorus (P) | ≤0.04 |
Sulfur (S) | ≤0.02 |