Grade dossier
422 Stainless Steel
422 stainless steel is a hardenable 12% chromium martensitic grade identified as UNS S42200. Nickel, molybdenum, tungsten and vanadium are added to retain strength and temper resistance at elevated temperature, making the grade especially relevant to steam and gas turbine components, compressor parts and other highly loaded power-generation or aerospace hardware.
Identity before substitution
Define 422 by specification, melt route and heat-treated condition
Carpenter identifies 422 as UNS S42200 and a hardenable 12% chromium martensitic stainless steel for service requiring higher elevated-temperature strength than 403 or 410. Universal Stainless publishes 422 as an AOD + ESR long-product grade for aerospace and power-generation markets. EN 1.4935 / X20CrMoWV12-1 is a widely used European cross-reference, but its chemistry limits are not identical to the current Carpenter S42200 analysis, so substitution must be approved against the governing specification and MTC.
422 stainless composition
Carpenter UNS S42200 type analysis
Do not merge UNS and EN limits into one acceptance table
The values at right follow Carpenter Technology’s current 422 / UNS S42200 alloy page. EN 1.4935 / X20CrMoWV12-1 uses a related but different chemistry window, especially for chromium, tungsten, vanadium, silicon and phosphorus/sulfur limits. State the exact material specification and edition on the PO, then accept the heat against its MTC.
| C | 0.20–0.25 |
|---|---|
| Mn | 1.00 max |
| Si | 1.00 max |
| P | 0.040 max |
| S | 0.030 max |
| Cr | 12.00–14.00 |
| Ni | 0.50–1.00 |
| Mo | 0.75–1.25 |
| W | 0.75–1.25 |
| V | 0.20–0.50 |
422 stainless properties
Separate source-specific heat-treated values from the ordered acceptance condition
Nickel Institute nominal hardened-and-tempered bar values
| Tensile strength | about 1000 MPa |
|---|---|
| 0.2% yield strength | about 862 MPa |
| Elongation | about 18% |
| Hardness | about 320 HB |
Condition and temperature indicators
| Carpenter design statement | elevated-temperature strength to about 649°C / 1200°F |
|---|---|
| Carpenter oxidation guide | continuous scaling resistance reported to about 760°C / 1400°F |
| Heat-treatment response | Hardenable; final properties depend on quench and temper condition |
| EN 1.4935 +QT800 reference | 850–1000 MPa tensile; 650 MPa proof min for ≤160 mm bar reference |
The 1000/862 MPa values are nominal hardened-and-tempered bar data published by the Nickel Institute, while the +QT800 line is an EN 1.4935 reference condition and is not an automatic S42200 acceptance requirement. Section size, melt route, heat treatment, test orientation and specification change the required properties. Use the ordered AMS/ASTM/EN/customer specification and the heat-specific MTC for final acceptance.
Selection boundary
Use 422 when hot strength and temper resistance justify a specialized martensitic grade
422 is strongest as a procurement choice when the part must carry load at elevated temperature and the design can use a hardened-and-tempered martensitic stainless steel. It is not a general-purpose corrosion upgrade and should not be selected from a room-temperature hardness table alone.
Good reasons to evaluate 422
Steam or gas turbine buckets, blades, rotors and related power-generation components
Compressor components needing strength and temper resistance above the normal 403/410 range
Aerospace and industrial hardware operating from room temperature toward roughly 649°C / 1200°F
Long-product parts where AOD + ESR melt quality, heat treatment and customer specification are controlled together
Stop and review before release
Applications where maximum corrosion resistance is the primary requirement rather than elevated-temperature strength
Using 1200°F or oxidation-scaling figures as a universal allowable design temperature without creep, stress and atmosphere review
Automatic substitution between S42200 and EN 1.4935 without reconciling chemistry, heat treatment and mechanical requirements
Welded fabrication without a qualified martensitic procedure, preheat/interpass control and post-weld heat-treatment review
Fabrication route
Treat hot working, machining, welding and heat treatment as one qualified route
Penn Stainless gives an initial forging/rolling range of about 1149–1177°C (2100–2150°F) and advises not to continue hot working below about 927°C (1700°F).
Machining requires rigid setup, sharp tools and consistent speed/feed. Penn specifically warns against galling and recommends keeping cutting conditions stable rather than allowing rubbing or work hardening.
Because 422 is a hardenable, relatively high-carbon martensitic grade, welding should be treated as a qualified procedure item. Define preheat, interpass control, filler choice and post-weld heat treatment from the code or customer specification.
Final strength is condition-dependent. Do not machine critical dimensions, approve hardness or release the part until the required quench/temper condition and any stress-relief sequence are tied to the drawing and PO.
422 stainless supplier evidence
Long-product form, melt route and specification are part of the material definition
Carpenter publishes 422 in bar and billet and lists AMS 5655 and ASTM A565 among the applicable specifications. Universal Stainless publishes 422 as AOD + ESR material in round bar, RCS billet, flat bar and ingot, with aerospace and power-generation approvals. Penn Stainless separately states that its inventory includes 422 round bar. These are attributable supplier/mill-source signals—not a claim that every 422 stainless supplier stocks every diameter or condition.
Carpenter forms: bar and billet
Universal forms: round bar, RCS billet, flat bar and ingot
Published melt route: AOD + ESR at Universal Stainless
Public stock evidence: Penn Stainless lists 422 round bar; diameter range is not published on the grade page
MTC and purchase-order checkpoint
Require heat identity, UNS S42200 or approved EN 1.4935 designation, governing specification and edition, melt route when required, final heat-treated condition, C/Cr/Ni/Mo/W/V analysis, mechanical results for the ordered condition, dimensions, surface/straightness requirements and any ultrasonic or supplementary inspection. A generic “422” certificate is not enough for turbine or aerospace release.
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Interactive selection check
Test 422 against the controlling procurement question
Procurement FAQ
Questions to close before ordering 422 stainless steel
What is 422 stainless steel?
422 is a hardenable martensitic stainless steel identified as UNS S42200. Carpenter positions it above 403/410 for strength at elevated temperature, while Universal Stainless describes an AOD + ESR route for power-generation and aerospace long products.
What is the EN equivalent of 422 stainless steel?
1.4935 / X20CrMoWV12-1 is a widely used European cross-reference. It is close in intended high-temperature martensitic service but its published chemistry window is not identical to the Carpenter S42200 analysis, so do not approve substitution without the exact standard, condition and MTC.
What are typical 422 stainless properties?
The Nickel Institute publishes nominal hardened-and-tempered bar values of about 1000 MPa tensile strength, 862 MPa 0.2% yield strength, 18% elongation and 320 HB. These are reference values rather than universal purchase minima; the ordered heat-treatment condition controls acceptance.
What are two important 422 application constraints?
First, 422 is not selected where maximum corrosion resistance is the controlling requirement. Second, elevated-temperature strength or oxidation figures are not standalone design allowables; stress, time, creep/rupture requirement, atmosphere and thermal cycling must be evaluated for the actual component.
What should a 422 RFQ include?
State UNS S42200 or approved EN 1.4935 designation, AMS/ASTM/EN/customer specification and edition, product form, dimensions, melt route if controlled, heat-treatment condition, required mechanical properties, service temperature and stress, machining/welding route, MTC and any UT or supplementary inspection requirement.
Sources, scope and RFQ
Trace the 422 chemistry, condition, melt route and hot-service limits before release
UNS S42200 identity, hardenable 12% Cr martensitic classification, C/Cr/Ni/Mo/W/V chemistry, elevated-temperature strength positioning to about 1200°F, AMS 5655 / ASTM A565 specifications, and bar/billet product forms.
AOD + ESR melt route, round bar/RCS billet/flat bar/ingot forms, aerospace and power-generation market focus, AMS 5655 / ASTM A565 plus customer specifications, and the 1.4935 trade-name cross-reference.
Nickel Institute nominal hardened-and-tempered bar data around 1000 MPa tensile, 862 MPa yield, 18% elongation and 320 HB; EN 1.4935 / X20CrMoWV12-1 chemistry and +QT800 data are used only as cross-reference evidence, not as automatic S42200 acceptance limits.
Public inventory statement for Alloy 422 round bar, turbine/aerospace applications, corrosion and oxidation cautions, machining guidance, and hot-working start/minimum temperatures. The public grade page does not state a 422 diameter range, so current size availability must be confirmed at RFQ.