Steel GX23CrMoV12-1-AC (Spheroidize annealed)
Heat-treated state
EN 1.4931
Only an intermediate foundry state — hard, brittle untempered martensite; never used in service.
Values for the AC condition
Other GX23CrMoV12-1 tempers and conditions
GX23CrMoV12-1 is listed in 5 conditions; see the grade overview at GX23CrMoV12-1.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Intermediate condition supplied for heavy rough machining or weld repair before final quench-and-temper. | 450 | 680 | 20 | 15 HRC | 3 % IACS |
Normalized and tempered | Used for thick-section castings where air cooling is preferred to avoid quench cracking; properties close to +QT1 in this air-hardening grade. | 560 | 780 | 17 | 23 HRC | 2.9 % IACS |
+QT1Default Quenched (air/oil from ~1020–1060 °C) and tempered ~680–730 °C | Standard EN 10213 supply condition for turbine casings and valve bodies — best balance of creep strength and toughness. | 580 | 800 | 17 | 24 HRC | — |
Quenched and tempered at lower temperature for higher strength | Choose when higher room-temperature yield strength is specified for valve bodies; toughness and creep ductility are somewhat lower. | 640 | 860 | 15 | 28 HRC | — |
ACThis page Spheroidize annealed | Only an intermediate foundry state — hard, brittle untempered martensite; never used in service. | 900 | 1,200 | 5 | 42 HRC | 2.7 % IACS |
What is GX23CrMoV12-1-AC?
GX23CrMoV12-1-AC is GX23CrMoV12-1 heat treated to AC — only an intermediate foundry state — hard, brittle untempered martensite; never used in service. GX23CrMoV12-1-AC has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 90% of steel grades. Elongation at break is 5% and the elastic modulus is 214 GPa (31 Msi). GX23CrMoV12-1-AC has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,450°C (2,642 °F). +QT1 is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- Good corrosion resistance — 45/100, better than 98% of steel grades
- High strength — 900 MPa (131 ksi), better than 90% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Limited ductility — 5%, worse than 98% of steel grades
- Low fracture toughness — 25 MPa·√m (22.8 ksi·√in), worse than 97% of steel grades
GX23CrMoV12-1-AC properties
Typical room-temperature values for GX23CrMoV12-1-AC; 22 are specific to this condition. Other listed values are GX23CrMoV12-1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GX23CrMoV12-1-AC has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
GX23CrMoV12-1-AC has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 90% of steel grades. Elongation at break is 5% and the elastic modulus is 214 GPa (31 Msi).
Thermal6
GX23CrMoV12-1-AC is rated for continuous service to 250°C (482 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical2
GX23CrMoV12-1-AC has an electrical resistivity of 6.4×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (45/100), better than 98% of steel grades.
Sustainability4
Producing a kilogram of GX23CrMoV12-1-AC takes about 33 MJ of energy and emits 2.5 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 70%.
Manufacturability8
GX23CrMoV12-1-AC's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (10/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GX23CrMoV12-1-AC
Is GX23CrMoV12-1 easy to machine?
Machine in the annealed or tempered condition with rigid setups, sharp carbide inserts, moderate speed and generous coolant; the grade work-hardens and is abrasive due to V carbides.
Can GX23CrMoV12-1 be welded?
Weldable with matching 12Cr-Mo-V or Ni-base filler using 250–350 °C preheat/interpass, slow cooling and mandatory post-weld temper at 700–740 °C.
Can GX23CrMoV12-1 be formed, bent or molded?
Supplied as sand or shell castings only — no cold forming; design generous fillets and controlled feeding to avoid hot tears in the air-hardening matrix.
What surface finishes work on GX23CrMoV12-1?
Cannot be anodized; use machined/ground sealing faces, passivation or hard-facing (Stellite) on valve seats and aluminide/thermal-spray coatings for steam-side protection.
GX23CrMoV12-1 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 – 0.26 | 0.23 |
| Si | ≤ 0.4 | 0.3 |
| Mn | 0.4 – 0.8 | 0.6 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Cr | 11.3 – 12.2 | 11.8 |
| Mo | 1 – 1.2 | 1.1 |
| Ni | 0.3 – 0.8 | 0.55 |
| V | 0.25 – 0.35 | 0.3 |
| Fe | balance | — |
GX23CrMoV12-1-AC — frequently asked
What is GX23CrMoV12-1-AC used for?
GX23CrMoV12-1-AC is typically used for steam turbine casings, high-temperature valve bodies and power plant components. In short: 12Cr cast steel to 550 °C; turbine-casing creep grade; air-hardening, PWHT mandatory.
What is the yield strength of GX23CrMoV12-1-AC?
GX23CrMoV12-1-AC has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is GX23CrMoV12-1-AC easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed or tempered condition with rigid setups, sharp carbide inserts, moderate speed and generous coolant; the grade work-hardens and is abrasive due to V carbides.
Can GX23CrMoV12-1-AC be welded?
Not readily — weldability is rated not recommended (10/100). Weldable with matching 12Cr-Mo-V or Ni-base filler using 250–350 °C preheat/interpass, slow cooling and mandatory post-weld temper at 700–740 °C.
What surface finishes work on GX23CrMoV12-1-AC?
Cannot be anodized; use machined/ground sealing faces, passivation or hard-facing (Stellite) on valve seats and aluminide/thermal-spray coatings for steam-side protection.
Can GX23CrMoV12-1-AC be formed, bent or molded?
Supplied as sand or shell castings only — no cold forming; design generous fillets and controlled feeding to avoid hot tears in the air-hardening matrix.
What is the maximum service temperature of GX23CrMoV12-1-AC?
GX23CrMoV12-1-AC is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between GX23CrMoV12-1 +QT1 and GX23CrMoV12-1-AC?
+QT1 is the default condition — standard EN 10213 supply condition for turbine casings and valve bodies — best balance of creep strength and toughness. AC: only an intermediate foundry state — hard, brittle untempered martensite; never used in service. Yield strength is 580 MPa in +QT1 versus 900 MPa in AC.
Sources
- EN 10213 — Steel castings for pressure purposes (creep-resisting grades) — CEN (2016)
- EN 10213-2 / material number 1.4931 data sheet — CEN (2007)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- Creep-resistant 12% Cr steel castings for steam turbine casings and valve bodies — foundry/producer literature (2020)
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.