022Cr25Ni7Mo4N (S25073) Super Duplex Stainless Steel Plate/Coil
022Cr25Ni7Mo4N (S25073) Super Duplex Stainless Steel Plate/Coil - GB/T 4237
Complete material data for 022Cr25Ni7Mo4N super duplex stainless steel (S25073) to GB/T 4237 standard, including chemical composition, mechanical properties, physical performance, and international equivalents.
Welding, forming, machining (with appropriate tools for high-strength material)
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022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Introduction
022Cr25Ni7Mo4N (UNS designation S25073) is a super duplex stainless steel combining high chromium, nickel, molybdenum, and nitrogen. It exhibits a balanced austenitic-ferritic microstructure that delivers exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-containing environments. Due to its low carbon content, it offers good weldability and high strength. The alloy is supplied as hot-rolled plate and coil per GB/T 4237, typically in solution-annealed and pickled or bright-annealed condition. It is widely used in aggressive chemical processing, marine systems, oil and gas production, and heat exchangers where high mechanical strength and superior corrosion resistance are required.
022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Chemical Composition
The chemical composition of 022Cr25Ni7Mo4N as specified in GB/T 4237 and referenced from GB/T 20878. The alloy is characterized by high chromium and molybdenum contents, balanced nickel, and deliberate nitrogen addition to stabilize the dual-phase structure and enhance corrosion resistance. Residual elements are strictly controlled to ensure optimal properties.
| Element | Specified Value | Remarks |
|---|---|---|
| Carbon (C) | ≤0.030 | Low carbon for weldability |
| Silicon (Si) | ≤0.80 | |
| Manganese (Mn) | ≤1.20 | |
| Phosphorus (P) | ≤0.035 | |
| Sulfur (S) | ≤0.020 | |
| Chromium (Cr) | 24.00 – 26.00 | Key for corrosion resistance |
| Nickel (Ni) | 6.00 – 8.00 | Balances austenite phase |
| Molybdenum (Mo) | 3.00 – 5.00 | Enhances pitting resistance |
| Nitrogen (N) | 0.24 – 0.32 | Strengthens and stabilizes duplex structure |
022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Thermal and Electrical Physical Properties
Representative physical properties at ambient temperature, unless otherwise noted. Data are based on published literature for super duplex stainless steel (S32750 / 1.4410). These values assist in design calculations involving heat transfer, thermal expansion, and dimensional stability.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.8 | g/cm³ | 20 °C |
| Modulus of elasticity (E) | 200 | GPa | 20 °C |
| Shear modulus (G) | 77 | GPa | Calculated from E and ν |
| Poisson's ratio (ν) | 0.30 | ||
| Thermal expansion coefficient (α) | 13.0 | 10⁻⁶/K | 20 – 100 °C |
| Thermal expansion coefficient (α) | 13.5 | 10⁻⁶/K | 20 – 200 °C |
| Thermal expansion coefficient (α) | 14.0 | 10⁻⁶/K | 20 – 300 °C |
| Thermal conductivity (λ) | 15 | W/(m·K) | 20 °C |
| Thermal conductivity (λ) | 17 | W/(m·K) | 100 °C |
| Thermal conductivity (λ) | 19 | W/(m·K) | 200 °C |
| Specific heat capacity | 475 | J/(kg·K) | 20 °C |
| Electrical resistivity (ρ_e) | 0.80 | μΩ·m | 20 °C |
022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Mechanical Properties
Mechanical properties for hot-rolled plate/coil in solution-annealed condition, tested at room temperature. Values are minimum requirements as per GB/T 4237 for thickness ≤ 75 mm. The material combines high tensile and yield strength with adequate elongation, making it suitable for highly stressed components.
| Property | Specified Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength (Rp0.2) | ≥550 | MPa | Solution annealed, thickness ≤75 mm |
| Tensile strength (Rm) | ≥750 | MPa | Solution annealed, thickness ≤75 mm |
| Elongation (A) | ≥25 | % | Gauge length 50 mm |
| Hardness | ≤310 | HBW | Solution annealed |
| Hardness | ≤32 | HRC | Solution annealed |
| Bend test | Bend diameter = 3t, 180° | – | No cracking after bending |
022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Fully Equivalent Material Standards and Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 4237 | 022Cr25Ni7Mo4N (S25073) | Domestic base standard |
| Europe | EN 10028-7 / EN 10088-2 | X2CrNiMoN25-7-4 (1.4410) | Chemically identical; same microstructural family |
| USA | ASTM A240 / A240M | UNS S32750 | Equivalent super duplex; widely accepted |
| International | ISO 15156 / NACE MR0175 | UNS S32750 / 1.4410 | Recognized for sour service |
022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Application Introduction
022Cr25Ni7Mo4N super duplex stainless steel is designed to operate in extremely corrosive environments where high mechanical strength is also necessary. The following lists typical fields of application, example products, and specific components that can be fabricated from this grade. Processing requires care due to its high strength and duplex solidification behavior; solution annealing after welding is often recommended to restore phase balance and corrosion resistance.
Product Applications: Hot-rolled plates for pressure vessels and storage tanks, Welded pipes and fittings for sea water cooling systems, Heat exchanger tube sheets and plates, Structural sections and profiles for offshore topside modules, Flanges, valves, and pump casings, Impellers and shafts for corrosive media
Processed into products: Tube sheets for shell-and-tube heat exchangers, Impellers and diffuser rings for centrifugal pumps, Shaped plates for desalination brine heaters, Weld overlay components for corrosion protection, Fasteners (bolts, nuts) for critical bolting applications (sour service), Separator internals in oil-water separation vessels
Application industries: Oil & Gas (offshore platforms, subsea equipment, pipelines), Chemical and Petrochemical Processing, Marine Engineering and Shipbuilding, Desalination Plants, Pulp and Paper Industry, Heating, Ventilation, and Air Conditioning (HVAC) – heat exchangers, Pharmaceutical and Food Processing (high-chloride environments)
022Cr25Ni7Mo4N Super Duplex Stainless Steel Plate/Coil Similar or Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China / International | GB/T 4237 / ASTM A240 | 022Cr25Ni7Mo4WCuN (S32760) | Contains extra Cu and W; higher pitting resistance; slightly different welding behavior |
| Europe | EN 10088-2 | X2CrNiMoCuWN25-7-4 (1.4501) | Equivalent to S32760; used in similar aggressive environments |
| China | GB/T 4237 | 022Cr23Ni5Mo3N (S22053) | Leaner duplex 2205; lower strength and corrosion resistance; cost-effective for less severe conditions |
Notes:
Special considerations:
- For thickness > 75 mm, mechanical properties may slightly decrease; consult manufacturer.
- Welding must use matching filler metal (e.g., AWS ER2594) and maintain interpass temperature below 150 °C.
- Post-weld heat treatment (solution annealing at ~1050–1120 °C followed by rapid quenching) is essential to restore corrosion resistance.
- This grade is included in NACE MR0175/ISO 15156 for H₂S service up to certain hardness and temperature limits; verify for specific sour environments.
- When ordering, specify cold forming requirements; excessive cold work may require intermediate annealing.
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