022Cr24Ni17Mo5Mn6NbN
022Cr24Ni17Mo5Mn6NbN: High-Strength Austenitic Stainless Steel for Severe Service
Complete material data for 022Cr24Ni17Mo5Mn6NbN nitrogen-strengthened austenitic stainless steel according to GB/T 4237, including chemical composition, mechanical properties, physical properties, and international equivalents.
Hot rolling, cold rolling (post-treatment), solution annealing, welding, machining
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022Cr24Ni17Mo5Mn6NbN Introduction
022Cr24Ni17Mo5Mn6NbN is a high-nitrogen, niobium-stabilized austenitic stainless steel developed to provide exceptional strength and corrosion resistance in demanding environments. It is supplied as hot-rolled plate and coil under GB/T 4237. The alloy achieves yield strength approximately twice that of conventional 304/316 grades while maintaining excellent toughness and ductility. Key features include:
- Superior resistance to pitting, crevice corrosion, and stress-corrosion cracking in chloride-containing media.
- High mechanical properties in the solution-annealed condition without requiring martensitic transformation.
- Good weldability and formability for heavy-section components.
- Widely recognized as the Chinese equivalent of UNS S20910 (Nitronic 50 / XM-19).
022Cr24Ni17Mo5Mn6NbN Chemical Composition
Chemical requirements of 022Cr24Ni17Mo5Mn6NbN as specified in GB/T 4237 (heat analysis). The balanced nitrogen‑niobium additions provide high strength and improved intergranular corrosion resistance. Sulfur and phosphorus are tightly controlled to ensure weld integrity.
| Element | Standard Value (wt%) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.030 | Low carbon for corrosion resistance |
| Silicon (Si) | ≤ 1.00 | |
| Manganese (Mn) | 4.00 – 6.00 | Austenite stabilizer and nitrogen solubility enhancer |
| Phosphorus (P) | ≤ 0.040 | |
| Sulfur (S) | ≤ 0.030 | |
| Chromium (Cr) | 20.50 – 23.50 | Primary element for oxidation and corrosion resistance |
| Nickel (Ni) | 11.50 – 13.50 | Austenite former |
| Molybdenum (Mo) | 1.50 – 3.00 | Improves pitting and crevice corrosion resistance |
| Nitrogen (N) | 0.20 – 0.40 | Significant solid-solution strengthener |
| Niobium (Nb) | 0.10 – 0.30 | Stabilizer against sensitization and grain refiner |
| Iron (Fe) | Balance |
022Cr24Ni17Mo5Mn6NbN Thermal, Electrical and Physical Properties
Typical physical data for 022Cr24Ni17Mo5Mn6NbN (equivalent to UNS S20910) in the solution-annealed condition. These values are derived from published engineering databases and are provided for design guidance; they are not specification requirements. The properties exhibit stability over a wide temperature range, making the alloy suitable for cryogenic as well as elevated-temperature service.
| Property | Typical Value | Unit | Condition / Reference |
|---|---|---|---|
| Density (ρ) | 7.88 | g/cm³ | At 20 °C |
| Modulus of Elasticity (E) | 193 | GPa | Tension, room temperature |
| Shear Modulus (G) | 73 | GPa | Torsion, room temperature |
| Poisson´s Ratio (ν) | 0.30 | — | Room temperature |
| Coefficient of Thermal Expansion (α) | 16.2 | 10⁻⁶/K | 20–100 °C |
| Coefficient of Thermal Expansion (α) | 17.0 | 10⁻⁶/K | 20–300 °C |
| Coefficient of Thermal Expansion (α) | 17.8 | 10⁻⁶/K | 20–500 °C |
| Thermal Conductivity (λ) | 14.0 | W/(m·K) | At 100 °C |
| Thermal Conductivity (λ) | 18.5 | W/(m·K) | At 500 °C |
| Specific Heat Capacity | 500 | J/(kg·K) | Room temperature |
| Electrical Resistivity (ρ_e) | 0.82 | µΩ·m | At 20 °C |
022Cr24Ni17Mo5Mn6NbN Mechanical Properties
Tensile and hardness requirements for 022Cr24Ni17Mo5Mn6NbN plates and coils in the solution-annealed condition according to GB/T 4237. These minimum values apply to thicknesses ≤ 75 mm. The high yield strength is a result of interstitial nitrogen strengthening.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (Rp0.2) | ≥ 380 | MPa | Room temperature, transverse specimen |
| Tensile Strength (Rm) | ≥ 690 | MPa | Room temperature, transverse specimen |
| Elongation after Fracture (A) | ≥ 35 | % | Gauge length 50 mm, 12.5 mm wide specimen |
| Hardness | ≤ 250 HBW or ≤ 100 HRB | — | Solution annealed condition |
022Cr24Ni17Mo5Mn6NbN Completely Equivalent Material Standards and Substitutable Grades
| Country / Region | Standard | Grade Designation | Remarks |
|---|---|---|---|
| USA | ASTM A240/A240M | UNS S20910 (XM-19) | Identical chemical composition; commonly referred to as Nitronic 50 |
| European Union | EN 10088-2 | 1.3964 – X2CrNiMnMoNbN21-16-5-3 | Direct equivalent; includes Nb stabilization |
| International | ISO 15510 | X2CrNiMnMoN21-15-5 (similar, check Nb content) | Composition closely aligned; verify niobium requirement |
022Cr24Ni17Mo5Mn6NbN Application Introduction
022Cr24Ni17Mo5Mn6NbN is designed for applications where high strength and superior corrosion resistance in aggressive environments are required simultaneously. Its excellent combination of mechanical and physical properties allows it to replace type 316 stainless steel in components subjected to high loads or where weight reduction is needed.
Product Applications: Pump shafts, impellers, and wear rings, Valve stems, seats, and bodies, High-strength fasteners (bolts, nuts, studs), Heat exchanger tubes and tube sheets, Pressure vessels for corrosive media, Structural components for offshore platforms, Seawater piping and fittings
Processed into products: Centrifugal pump shafts for sour water service, Needle valves for high-pressure chemical injection, Anchor bolts for submerged marine structures, Compressor disks in acidic gas environments, Bearing sleeves for corrosive slurry pumps, Surgical implants (as an alternative to 316LVM when higher strength is needed), Scrubber internals and mist eliminators
Application industries: Marine and offshore engineering, Chemical and petrochemical processing, Pulp and paper industry, Power generation (nuclear and fossil), Oil and gas extraction equipment, Pollution control systems, Food processing (high chloride environments)
022Cr24Ni17Mo5Mn6NbN Similar / Near-Equivalent Alternative Materials
| Country / Region | Standard | Grade Designation | Remarks |
|---|---|---|---|
| USA | ASTM A276 / A479 | UNS S21800 (Nitronic 60) | Higher strength and galling resistance, but different Cr-Ni-Mn balance; no Mo |
| USA | ASTM A240 | UNS S20400 (201L variant) | Lower alloy content; moderate strength and corrosion resistance |
| European Union | EN 10088-2 | 1.3952 – X2CrNiMnMoN19-13-5 | Similar nitrogen-strengthened grade with slightly lower Cr and Mo |
| China | GB/T 4237 | 06Cr17Ni12Mo2 (316) | Classic austenitic stainless steel; much lower strength but excellent availability |
Notes:
For optimum corrosion resistance, the material must be solution-annealed and rapidly cooled. Welding consumables should match the base metal composition (e.g., ER209 filler). Heat treatment in the range 540–900°C can cause precipitation of sigma and chi phases, leading to embrittlement and reduced corrosion resistance; thus, service temperatures in this interval should be carefully evaluated. The high work-hardening rate demands rigid tooling and sharp tools during machining.
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