Steel GX15CrMo5-QT (Quenched and tempered)
Heat-treated state
ASTM A217 Gr. C5 · EN 1.7365
Choose when higher yield strength or thick-section uniformity is needed; temper high enough to stay within the 241 HB ceiling for valve bodies.
Values for the QT condition
Other GX15CrMo5 tempers and conditions
GX15CrMo5 is listed in 4 conditions; see the grade overview at GX15CrMo5.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition for heavy rough machining or major weld repair; must be re-normalized and tempered before pressure service. | 340 | 560 | 26 | 165 HB | 4 % IACS |
As-cast + stress relieved | Only for non-code parts or trial castings — brittle as-cast structure with poor and scattered impact properties. | 450 | 700 | 10 | 21 HRC | 3.7 % IACS |
N+TDefault Normalized and tempered | Standard supply condition for pressure castings — balanced strength, creep resistance and 27 J minimum impact energy. | 480 | 680 | 22 | 200 HB | — |
QTThis page Quenched and tempered | Choose when higher yield strength or thick-section uniformity is needed; temper high enough to stay within the 241 HB ceiling for valve bodies. | 580 | 760 | 18 | 22 HRC | — |
What is GX15CrMo5-QT?
GX15CrMo5-QT is GX15CrMo5 heat treated to QT — choose when higher yield strength or thick-section uniformity is needed; temper high enough to stay within the 241 HB ceiling for valve bodies. GX15CrMo5-QT has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 75% of steel grades. Elongation at break is 18% and the elastic modulus is 213 GPa (30.9 Msi). GX15CrMo5-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). N+T 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 — 25/100, better than 92% of steel grades
- High strength — 580 MPa (84.1 ksi), better than 75% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Low electrical conductivity — 3.8 % IACS, worse than 84% of steel grades
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
GX15CrMo5-QT properties
Typical room-temperature values for GX15CrMo5-QT; 12 are specific to this condition. Other listed values are GX15CrMo5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GX15CrMo5-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).
Mechanical17
GX15CrMo5-QT has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 75% of steel grades. Elongation at break is 18% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal6
GX15CrMo5-QT is rated for continuous service to 600°C (1,112 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
GX15CrMo5-QT conducts electricity at 3.8 % IACS, worse than 84% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of GX15CrMo5-QT takes about 32 MJ of energy and emits 2.5 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 75%.
Manufacturability8
GX15CrMo5-QT's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (40/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GX15CrMo5-QT
Is GX15CrMo5 easy to machine?
Machine in the N+T or annealed condition with rigid setups and coated carbide at moderate speed; Cr carbides are abrasive and skin/scale should be removed first.
Can GX15CrMo5 be welded?
P-No.5B material — use matching 5Cr-0.5Mo (E502/ER80S-B6) filler, 200–300 °C preheat with interpass control and mandatory PWHT at 700–750 °C to avoid hard martensite and delayed cracking.
Can GX15CrMo5 be formed, bent or molded?
Supplied as sand/investment castings; design generous fillets and risers, control section transitions and always heat treat, since as-cast structure is brittle.
What surface finishes work on GX15CrMo5?
Shot blast and prime or use high-temperature aluminium/silicone paint; for oxidizing service above 600 °C consider aluminizing — no anodizing possible.
GX15CrMo5 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: 0.12–0.19; ASTM A217 C5: 0.20 max | 0.12 – 0.2 | 0.16 |
| SiEN limit 0.60 max | ≤ 0.75 | 0.45 |
| Mn | 0.4 – 0.7 | 0.55 |
| PEN 10213: 0.025 max | ≤ 0.04 | 0.02 |
| SEN 10213: 0.020 max | ≤ 0.05 | 0.02 |
| CrEN 10213: 4.0–6.0 | 4 – 6.5 | 5 |
| Mo | 0.45 – 0.65 | 0.55 |
| Niresidual | ≤ 0.5 | 0.2 |
| Fe | balance | — |
GX15CrMo5-QT — frequently asked
What is GX15CrMo5-QT used for?
GX15CrMo5-QT is typically used for high-temperature valve bodies, petrochemical pressure castings and furnace and boiler fittings. In short: A217 C5 heat-resistant casting; oxidation resistance to 620 °C; 5Cr step above WC6.
What is the yield strength of GX15CrMo5-QT?
GX15CrMo5-QT has a typical yield strength of 580 MPa (84.1 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 75% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is GX15CrMo5-QT easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the N+T or annealed condition with rigid setups and coated carbide at moderate speed; Cr carbides are abrasive and skin/scale should be removed first.
Can GX15CrMo5-QT be welded?
With care — weldability is rated fair (40/100). P-No.5B material — use matching 5Cr-0.5Mo (E502/ER80S-B6) filler, 200–300 °C preheat with interpass control and mandatory PWHT at 700–750 °C to avoid hard martensite and delayed cracking.
What surface finishes work on GX15CrMo5-QT?
Shot blast and prime or use high-temperature aluminium/silicone paint; for oxidizing service above 600 °C consider aluminizing — no anodizing possible.
Can GX15CrMo5-QT be formed, bent or molded?
Supplied as sand/investment castings; design generous fillets and risers, control section transitions and always heat treat, since as-cast structure is brittle.
What is the maximum service temperature of GX15CrMo5-QT?
GX15CrMo5-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 GX15CrMo5 N+T and GX15CrMo5-ANN?
N+T is the default condition — standard supply condition for pressure castings — balanced strength, creep resistance and 27 J minimum impact energy. ANN: softest condition for heavy rough machining or major weld repair; must be re-normalized and tempered before pressure service. Yield strength is 480 MPa in N+T versus 340 MPa in ANN.
Sources
- ASTM A217/A217M — Martensitic Stainless and Alloy Steel Castings for Pressure-Containing Parts for High-Temperature Service (Gr. C5) — ASTM International (2021)
- EN 10213 — Steel castings for pressure purposes (GX15CrMo5, 1.7365) — CEN (2016)
- GB/T 16253 / JB/T 5263 ZG15Cr5Mo (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASME BPVC Section II Part D — physical property tables for 5Cr-0.5Mo — ASME (2023)
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.