Stainless Steel CA28MWV N+T
Heat-treated state · default condition
ASTM CA28MWV · UNS J91422
N+T = normalized and tempered
Standard ASTM A217 delivery condition for steam-turbine casings and valve bodies; meets 1000 MPa UTS / 690 MPa YS with tempered-martensite creep stability.
Values for the N+T condition
Other CA28MWV tempers and conditions
CA28MWV is listed in 5 conditions; see the grade overview at CA28MWV.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Foundry soft-anneal (~845–900 °C, slow cool) used only to rough-machine heavy castings before final normalize-and-temper. | 500 | 760 | 18 | 21 HRC | — |
N+T plus post-weld stress relief | Condition of finished weld-repaired or fabricated castings; slight strength drop but restored HAZ toughness and low residual stress. | 730 | 1,000 | 14 | 31 HRC | 2.9 % IACS |
Double tempered (two tempers ≥ 690 °C) for long-term high-temperature… | Specified for turbine casings held near 550–600 °C for tens of thousands of hours; second temper decomposes retained austenite and stabilises toughness. | 740 | 1,010 | 15 | 31 HRC | 2.9 % IACS |
N+TDefaultThis page Normalized and tempered | Standard ASTM A217 delivery condition for steam-turbine casings and valve bodies; meets 1000 MPa UTS / 690 MPa YS with tempered-martensite creep stability. | 760 | 1,035 | 13 | 32 HRC | — |
Quenched and tempered | Quenched version for heavy sections where air cooling is too slow to fully harden the core; slightly higher strength than N+T. | 800 | 1,080 | 12 | 34 HRC | — |
What is CA28MWV N+T?
CA28MWV N+T is CA28MWV heat treated to N+T — standard ASTM A217 delivery condition for steam-turbine casings and valve bodies; meets 1000 MPa UTS / 690 MPa YS with tempered-martensite creep stability. CA28MWV N+T has a yield strength of 760 MPa (110 ksi) and a tensile strength of 1,035 MPa (150 ksi) — stronger than 94% of stainless steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). CA28MWV N+T has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- Low embodied carbon — 3 kg CO₂/kg, better than 97% of stainless steel grades
- High strength — 760 MPa (110 ksi), better than 94% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% 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
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Limited ductility — 13%, worse than 93% of stainless steel grades
- Needs corrosion protection — 42/100, worse than 90% of stainless steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 88% of stainless steel grades
- Difficult to weld — 30/100, worse than 88% of stainless steel grades
CA28MWV N+T properties
Typical room-temperature values for CA28MWV N+T; 11 are specific to this condition. Other listed values are CA28MWV reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CA28MWV N+T has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
CA28MWV N+T has a yield strength of 760 MPa (110 ksi) and a tensile strength of 1,035 MPa (150 ksi) — stronger than 94% of stainless steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
CA28MWV N+T is rated for continuous service to 593°C (1,099 °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 10.8 µm/m·K (6 µin/in·°F).
Electrical3
CA28MWV N+T conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of CA28MWV N+T takes about 39 MJ of energy and emits 3 kg of CO₂ — less than 98% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
CA28MWV N+T's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability poor (30/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CA28MWV N+T
Is CA28MWV easy to machine?
Machine in the soft-annealed condition where possible; in N+T at ~300 HB use rigid setups, coated carbide, low speed (60–90 m/min) and heavy positive feeds to cut under the work-hardened skin.
Can CA28MWV be welded?
Weldable with matching 12Cr-Mo-W-V or E410NiMo consumables only with 250–300 °C preheat/interpass, no cooling below ~120 °C before PWHT, and a 690–730 °C temper; hydrogen control is critical.
Can CA28MWV be formed, bent or molded?
Casting alloy — no cold forming; feed heavy sections generously, avoid abrupt section changes and normalize-and-temper the whole casting to homogenize the as-cast dendritic structure.
What surface finishes work on CA28MWV?
Shot blast and pickle/passivate for a stable Cr-oxide film; can be hard-chrome plated or nitrided on seating faces, and takes a good mechanical polish but is not anodizable.
CA28MWV 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 – 0.28 | 0.24 |
| Mn | 0.5 – 1 | 0.75 |
| Si | ≤ 1 | 0.6 |
| Pimpurity | ≤ 0.03 | — |
| Simpurity | ≤ 0.03 | — |
| Cr | 11 – 12.5 | 11.8 |
| Ni | 0.5 – 1 | 0.75 |
| Mo | 0.9 – 1.25 | 1.05 |
| W | 0.9 – 1.25 | 1.05 |
| Vforms fine VC/VN for creep strength | 0.2 – 0.3 | 0.25 |
| Fe | balance | — |
CA28MWV N+T — frequently asked
What is CA28MWV N+T used for?
CA28MWV N+T is typically used for steam turbine casings, high-pressure steam valves and power generation components. In short: highest-strength CA casting; creep-resistant steam grade; lower ductility than CA15.
What is the yield strength of CA28MWV N+T?
CA28MWV N+T has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 1,035 MPa (150 ksi) — stronger than 94% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is CA28MWV N+T easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Machine in the soft-annealed condition where possible; in N+T at ~300 HB use rigid setups, coated carbide, low speed (60–90 m/min) and heavy positive feeds to cut under the work-hardened skin.
Can CA28MWV N+T be welded?
Not readily — weldability is rated poor (30/100). Weldable with matching 12Cr-Mo-W-V or E410NiMo consumables only with 250–300 °C preheat/interpass, no cooling below ~120 °C before PWHT, and a 690–730 °C temper; hydrogen control is critical.
What surface finishes work on CA28MWV N+T?
Shot blast and pickle/passivate for a stable Cr-oxide film; can be hard-chrome plated or nitrided on seating faces, and takes a good mechanical polish but is not anodizable.
Can CA28MWV N+T be formed, bent or molded?
Casting alloy — no cold forming; feed heavy sections generously, avoid abrupt section changes and normalize-and-temper the whole casting to homogenize the as-cast dendritic structure.
What is the maximum service temperature of CA28MWV N+T?
CA28MWV N+T is rated for continuous use to about 593°C (1,099 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CA28MWV N+T and CA28MWV-ANN?
N+T is the default condition — standard ASTM A217 delivery condition for steam-turbine casings and valve bodies; meets 1000 MPa UTS / 690 MPa YS with tempered-martensite creep stability. ANN: foundry soft-anneal (~845–900 °C, slow cool) used only to rough-machine heavy castings before final normalize-and-temper. Yield strength is 760 MPa in N+T versus 500 MPa in ANN.
Sources
- ASTM A217/A217M — Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts, Suitable for High-Temperature Service — ASTM International (2021)
- ASME B16.34 — Valves: Flanged, Threaded, and Welding End (material rating tables) — ASME (2020)
- ASM Specialty Handbook: Heat-Resistant Materials / Cast Stainless Steels — ASM International (1997)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM International (1995)
- UNS J91422 alloy record (Metals & Alloys in the Unified Numbering System) — 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.