Steel GX15CrMo9-1 +QT (Quenched and tempered)
Heat-treated state
ASTM A217 Gr. C12 · EN 1.7376
Choose for heavy-section castings where accelerated cooling is needed to obtain uniform tempered martensite and higher yield strength.
Values for the +QT condition
Other GX15CrMo9-1 tempers and conditions
GX15CrMo9-1 is listed in 4 conditions; see the grade overview at GX15CrMo9-1.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Soft ferrite+carbide condition for rough machining or repair welding of castings; must be re-normalized and tempered before pressure service. | 255 | 470 | 24 | 160 HB | 3.2 % IACS |
+NTDefault Normalized and tempered | Standard pressure-part condition: normalize ~1040–1080 °C, temper ≥730 °C for creep strength plus code-compliant ductility. | 320 | 520 | 20 | 185 HB | — |
+QTThis page Quenched and tempered | Choose for heavy-section castings where accelerated cooling is needed to obtain uniform tempered martensite and higher yield strength. | 385 | 570 | 18 | 205 HB | — |
As fabricated | Non-code condition seen only between pouring and heat treatment: hard, brittle as-quenched martensite; never supplied for pressure duty. | 500 | 700 | 7 | 31 HRC | 3 % IACS |
What is GX15CrMo9-1 +QT?
GX15CrMo9-1 +QT is GX15CrMo9-1 heat treated to +QT — choose for heavy-section castings where accelerated cooling is needed to obtain uniform tempered martensite and higher yield strength. GX15CrMo9-1 +QT has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 65% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi). GX15CrMo9-1 +QT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,450°C (2,642 °F). +NT is the default condition FabDigit quotes; +QT is available on request or by drawing note.
Advantages
- High service temperature — 600°C (1,112 °F), better than 98% of steel grades
- Good corrosion resistance — 30/100, better than 95% of steel grades
Limitations
- Low electrical conductivity — 3.1 % IACS, worse than 89% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Poor heat conductor — 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
GX15CrMo9-1 +QT properties
Typical room-temperature values for GX15CrMo9-1 +QT; 10 are specific to this condition. Other listed values are GX15CrMo9-1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GX15CrMo9-1 +QT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
GX15CrMo9-1 +QT has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 65% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
GX15CrMo9-1 +QT is rated for continuous service to 600°C (1,112 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
GX15CrMo9-1 +QT conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of GX15CrMo9-1 +QT takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 70%.
Manufacturability8
GX15CrMo9-1 +QT's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (40/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GX15CrMo9-1 +QT
Is GX15CrMo9-1 easy to machine?
Machine in the tempered condition with rigid setups, coated carbide and moderate speeds; remove the abrasive cast skin first and expect work hardening near 200 HB.
Can GX15CrMo9-1 be welded?
Weldable with matching 9Cr-1Mo (E505/ER80S-B8) consumables using 200–300 °C preheat, controlled interpass and mandatory 730–760 °C PWHT to avoid hard, crack-prone martensite.
Can GX15CrMo9-1 be formed, bent or molded?
Supplied as sand or investment castings only — no cold forming; design generous fillets and directional feeding, and control cooling to prevent quench cracks in heavy sections.
What surface finishes work on GX15CrMo9-1?
Not anodizable; shot blast and use high-temperature aluminum/silicone paint or aluminizing for atmospheric protection, and machined seats for valve sealing surfaces.
GX15CrMo9-1 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 |
|---|---|---|
| CEN 10213 GX15CrMo9-1; ASTM A217 C12 allows 0.20 max | 0.08 – 0.2 | 0.15 |
| SiEN often limits ≤0.60 | ≤ 1 | 0.5 |
| Mn | 0.35 – 0.7 | 0.5 |
| PA217: 0.040 max | ≤ 0.03 | — |
| SA217: 0.045 max | ≤ 0.02 | — |
| Cr | 8 – 10 | 9 |
| Mo | 0.9 – 1.2 | 1 |
| Niresidual | ≤ 0.4 | — |
| Fe | balance | — |
GX15CrMo9-1 +QT — frequently asked
What is GX15CrMo9-1 +QT used for?
GX15CrMo9-1 +QT is typically used for high-temperature valve bodies, power plant fittings and petrochemical pressure castings. In short: cast equivalent of P9; 600 °C pressure service; highest-temperature CrMo casting.
What is the yield strength of GX15CrMo9-1 +QT?
GX15CrMo9-1 +QT has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is GX15CrMo9-1 +QT easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the tempered condition with rigid setups, coated carbide and moderate speeds; remove the abrasive cast skin first and expect work hardening near 200 HB.
Can GX15CrMo9-1 +QT be welded?
With care — weldability is rated fair (40/100). Weldable with matching 9Cr-1Mo (E505/ER80S-B8) consumables using 200–300 °C preheat, controlled interpass and mandatory 730–760 °C PWHT to avoid hard, crack-prone martensite.
What surface finishes work on GX15CrMo9-1 +QT?
Not anodizable; shot blast and use high-temperature aluminum/silicone paint or aluminizing for atmospheric protection, and machined seats for valve sealing surfaces.
Can GX15CrMo9-1 +QT be formed, bent or molded?
Supplied as sand or investment castings only — no cold forming; design generous fillets and directional feeding, and control cooling to prevent quench cracks in heavy sections.
What is the maximum service temperature of GX15CrMo9-1 +QT?
GX15CrMo9-1 +QT is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between GX15CrMo9-1 +NT and GX15CrMo9-1-F?
+NT is the default condition — standard pressure-part condition: normalize ~1040–1080 °C, temper ≥730 °C for creep strength plus code-compliant ductility. F: non-code condition seen only between pouring and heat treatment: hard, brittle as-quenched martensite; never supplied for pressure duty. Yield strength is 320 MPa in +NT versus 500 MPa in F.
Sources
- ASTM A217/A217M — Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts (Gr. C12) — ASTM International (2021)
- EN 10213 — Steel castings for pressure purposes (GX15CrMo9-1, 1.7376) — CEN (2016)
- ASME BPVC Section II Part D — Material properties (9Cr-1Mo) — ASME (2023)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- GB/T 16253 — (ZG1Cr9Mo class) — SAC (2019)
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.