Material Data Sheet and Technical Overview
The stainless steel grade 1.4547, commonly known as UNS S31254, AISI 254SMO, or simply 254SMO stainless steel, is an austenitic chromium-nickel-molybdenum steel highly resistant to pitting, crevice, and surface corrosion. Due to its exceptional PREN (Pitting Resistance Equivalent Number) value ranging from 42.2 to 47.6, the 1.4547 material is particularly suited for aggressive environments, including seawater, making it widely utilized in offshore applications.
Standards and Identifications of Stainless Steel 1.4547
EN: 1.4547 DIN: X1CrNiMoCuN20-18-7 AISI: 254SMO UNS: S31254 Alternative designations include 254SMO stainless steel, S31254 material, SMO 253, 1.4547 duplex, X1CrNiMoCuN20-18-7, and F44 data sheet.
Material Profile: Austenitic Stainless Steel 254SMO
The 1.4547 stainless steel (254SMO) offers outstanding corrosion resistance, particularly:- Exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking
- Highly effective in chloride-rich environments, including seawater
- Reliable performance in aggressive chemical and petrochemical conditions
- Superior corrosion resistance in both supplied condition and after welding
Typical Applications of 1.4547 Stainless Steel
The 254SMO stainless steel is widely utilized in industries requiring superior corrosion resistance, such as:
- Chemical and petrochemical industries
- Food processing industry
- Mechanical engineering
- Offshore technology
- Seawater desalination plants
- Flue gas desulfurization
- Shipbuilding
Due to its excellent mechanical properties, 254SMO round bar and other product forms of UNS S31254 stainless steel are especially valuable in applications where superior corrosion resistance and durability in aggressive environments are critical.
Chemical Composition of S31254 Material
(weight proportion in %)
| Value | Proportion % |
|---|---|
| Carbon (C) | min. 0% - max. 0.02% |
| Manganese (Mn) | min. 0% - max. 1.00% |
| Silicon (Si) | min. 0% - max. 0.70% |
| Phosphorus (P) | min. 0% - max. 0.030% |
| Sulfur (S) | min. 0% - max. 0.010% |
| Chromium (Cr) | 19.5 – 20.5% |
| Nickel (Ni) | 17.5 – 18.5% |
| Molybdenum (Mo) | 6.0 – 7.0% |
| Nitrogen (N) | 0.18 – 0.25% |
| Copper (Cu) | 0.50 – 1.00% |
Mechanical Properties at 20 °C
| Hardness (HB) | ≤ 215 |
| Yield strength (Rp₀.₂) | ≥ 200 N/mm² |
| Tensile strength (Rm) | 500 – 700 N/mm² |
| Elongation (A5,65) | ≥ 40% |
| Elastic modulus | 200 kN/mm² |
Physical Properties of 254SMO Stainless Steel
- Density: 8.0 kg/dm³
- Electrical resistance: 0.85 Ω·mm²/m
- Thermal conductivity: 13 W/m·K
- Specific heat capacity: 500 J/kg·K
- Magnetizability: practically non-magnetic
Temperature Behavior and Heat Resistance
The 254SMO material is suitable for use in demanding temperature conditions. Key characteristics include:
- Service temperature suitability for demanding environments, especially offshore and seawater applications
- Excellent resistance to thermal stress
Processing and Machining
- Weldability: Excellent with all common welding processes; minimal heat input recommended
- Machinability: Moderate, prone to work hardening; use lower cutting speeds and greater cutting depths
- Cold forming: Suitable
- Polishability: Suitable
- Forging: Compatible with open-die and drop forging processes
Assignment to current and older standards
- Designation according to DIN: X 1 Cr Ni Mo Cu N
- EN: 1.4547
- UNS: S 31254
- VdTüV: 473
Tables and rates
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