Stainless Steel 422 · heat-treated state
Stainless Steel 422 N&T
Properties of the N&T condition, compared with the other 422 tempers.
Air-cooled from austenitizing then tempered; used for heavy forgings and sections where oil quenching risks cracking.
What is 422 N&T?
422 N&T is 422 heat treated to N&T — air-cooled from austenitizing then tempered; used for heavy forgings and sections where oil quenching risks cracking. 422 N&T has a yield strength of 790 MPa (115 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 96% of stainless steel grades. Elongation at break is 17% and the elastic modulus is 213 GPa (30.9 Msi). 422 N&T has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,425°C (2,597 °F). Hardened & Tempered is the default condition FabDigit quotes; N&T is available on request or by drawing note.
Advantages
- High strength — 790 MPa (115 ksi), better than 96% of stainless steel grades
- Low embodied carbon — 3.5 kg CO₂/kg, better than 88% of stainless steel grades
- Conducts heat well — 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades
Limitations
- Difficult to weld — 30/100, worse than 89% of stainless steel grades
- Limited ductility — 17%, worse than 86% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
- Low fracture toughness — 75 MPa·√m (68.3 ksi·√in), worse than 85% of stainless steel grades
- Needs corrosion protection — 45/100, worse than 85% of stainless steel grades
422 N&T properties
Typical room-temperature values for 422 N&T — 9 properties are specific to this condition; the rest are grade-level values shared by every 422 temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
422 N&T has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
422 N&T has a yield strength of 790 MPa (115 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 96% of stainless steel grades. Elongation at break is 17% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal5
422 N&T is rated for continuous service to 620°C (1,148 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades. Thermal expansion is 11.2 µm/m·K (6.22 µin/in·°F).
Electrical2
422 N&T has an electrical resistivity of 6×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 85% of stainless steel grades.
Sustainability4
Producing a kilogram of 422 N&T takes about 53 MJ of energy and emits 3.5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 40%.
Manufacturability7
422 N&T's machinability is fair (35/100, better than 51% of stainless steel grades); weldability poor (30/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 422 tempers and conditions
422 is also supplied in 4 other conditions. The full side-by-side table is on the 422 overview.
- Hardened & TemperedDefaultStandard turbine-blade / high-temperature bolting condition: best balance of strength, creep resistance and toughness to 650 °C.860 MPa yield · 32 HRC
- H&T 38-42 HRCChoose when maximum room-temperature strength and wear resistance matter more than toughness or long-term 600 °C stability.1,030 MPa yield · 40 HRC
- N&TAir-cooled from austenitizing then tempered; used for heavy forgings and sections where oil quenching risks cracking.790 MPa yield · 32 HRC
- AnnealedSoftest supply condition for machining, straightening or before hardening; not a service condition for high-temperature parts.590 MPa yield · 22 HRC
Working with 422 N&T
Is 422 easy to machine?
Machine in the annealed or high-temper condition with rigid setups, sharp carbide tooling, low speed (~25–45 m/min) and heavy feeds; the W/V carbides are abrasive and work-hardening is significant.
Can 422 be welded?
Weldable only with 400 °C-class preheat, matching or 410NiMo filler, interpass control and mandatory post-weld temper at ~700 °C — otherwise cold cracking of the martensitic HAZ.
Can 422 be formed, bent or molded?
Hot work at 1100–1150 °C with slow cooling and immediate annealing; cold forming is essentially limited to gentle straightening.
What surface finishes work on 422?
Passivate after machining, or apply steam/black-oxide, chromizing or aluminizing for high-temperature oxidation; takes a good mechanical polish but never anodizes.
422 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.2 – 0.25 | 0.22 |
| Mn | 0.5 – 1 | 0.75 |
| Si | ≤ 0.5 | 0.35 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 11 – 12.5 | 11.75 |
| Ni | 0.5 – 1 | 0.75 |
| Mo | 0.9 – 1.25 | 1 |
| W | 0.9 – 1.25 | 1 |
| V | 0.2 – 0.3 | 0.25 |
| Fe | balance | — |
422 N&T — frequently asked
What is 422 N&T used for?
422 N&T is typically used for steam turbine blades, high-temperature bolting and studs, valve bodies and stems for steam service, turbine rotor and disc forgings, pump shafts for hot service and compressor components. In short: high-temp martensitic forging.
What is the yield strength of 422 N&T?
422 N&T has a typical yield strength of 790 MPa (115 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 96% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 422 N&T easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machine in the annealed or high-temper condition with rigid setups, sharp carbide tooling, low speed (~25–45 m/min) and heavy feeds; the W/V carbides are abrasive and work-hardening is significant.
Can 422 N&T be welded?
Not readily — weldability is rated poor (30/100). Weldable only with 400 °C-class preheat, matching or 410NiMo filler, interpass control and mandatory post-weld temper at ~700 °C — otherwise cold cracking of the martensitic HAZ.
What surface finishes work on 422 N&T?
Passivate after machining, or apply steam/black-oxide, chromizing or aluminizing for high-temperature oxidation; takes a good mechanical polish but never anodizes.
Can 422 N&T be formed, bent or molded?
Hot work at 1100–1150 °C with slow cooling and immediate annealing; cold forming is essentially limited to gentle straightening.
What is the maximum service temperature of 422 N&T?
422 N&T is rated for continuous use to about 620°C (1,148 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 422 N&T?
Yes — 422 N&T is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A565/A565M — Martensitic Stainless Steel Bars for High-Temperature Service (Grade 616 / S42200) — ASTM International (2019)
- ASTM A276/A479 — Stainless Steel Bars and Shapes — ASTM International (2022)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Unified Numbering System for Metals and Alloys (UNS S42200) — SAE/ASTM (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.