Steel G30CrMoV6-4 +QT1
Heat-treated state · default condition
EN 1.7725
+QT1 = quenched and tempered, 850–1000 MPa strength class
Standard supply condition: best balance of 700 MPa+ yield and usable toughness for thick-section pressure and structural castings.
Values for the +QT1 condition
Other G30CrMoV6-4 tempers and conditions
G30CrMoV6-4 is listed in 4 conditions; see the grade overview at G30CrMoV6-4.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Soft intermediate condition used by foundries for rough machining, straightening and repair welding before final quench and temper. | 420 | 700 | 18 | 17 HRC | 7.6 % IACS |
Normalized | Grain-refining treatment for large or complex castings that cannot be liquid quenched; lower strength than +QT conditions. | 560 | 800 | 15 | 23 HRC | 7.4 % IACS |
+QT1DefaultThis page Quenched and tempered, 850–1000 MPa strength class | Standard supply condition: best balance of 700 MPa+ yield and usable toughness for thick-section pressure and structural castings. | 750 | 920 | 14 | 29 HRC | — |
Quenched and tempered, 1000–1150 MPa strength class | Lower-temperature temper for maximum strength and wear resistance where reduced ductility and impact energy are acceptable. | 900 | 1,070 | 11 | 35 HRC | — |
What is G30CrMoV6-4 +QT1?
G30CrMoV6-4 +QT1 is G30CrMoV6-4 heat treated to +QT1 — standard supply condition: best balance of 700 MPa+ yield and usable toughness for thick-section pressure and structural castings. G30CrMoV6-4 +QT1 has a yield strength of 750 MPa (109 ksi) and a tensile strength of 920 MPa (133 ksi) — stronger than 84% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). G30CrMoV6-4 +QT1 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- High strength — 750 MPa (109 ksi), better than 84% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
G30CrMoV6-4 +QT1 properties
Typical room-temperature values for G30CrMoV6-4 +QT1; 18 are specific to this condition. Other listed values are G30CrMoV6-4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G30CrMoV6-4 +QT1 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
G30CrMoV6-4 +QT1 has a yield strength of 750 MPa (109 ksi) and a tensile strength of 920 MPa (133 ksi) — stronger than 84% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G30CrMoV6-4 +QT1 is rated for continuous service to 450°C (842 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
G30CrMoV6-4 +QT1 conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of G30CrMoV6-4 +QT1 takes about 24 MJ of energy and emits 2 kg of CO₂ — less than 97% of steel grades. Typical recycled content is 75%.
Manufacturability7
G30CrMoV6-4 +QT1's machinability is fair (40/100, worse than 77% of 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 G30CrMoV6-4 +QT1
Is G30CrMoV6-4 easy to machine?
Machine mostly in the annealed/normalized state; in +QT (280–350 HB) use rigid setups, coated carbide, ~80–140 m/min and positive feed to break through the cast skin.
Can G30CrMoV6-4 be welded?
Weldable only with matching low-hydrogen Cr-Mo consumables, 250–350 °C preheat/interpass and 620–680 °C PWHT below the tempering temperature; upgrade/repair welds should precede final Q&T.
Can G30CrMoV6-4 be formed, bent or molded?
Sand or investment cast with generous feeders — steel shrinkage ~2%; avoid abrupt section changes, and always normalize/homogenize before hardening to break down dendritic structure.
What surface finishes work on G30CrMoV6-4?
No inherent corrosion resistance: shot blast, then paint, phosphate, zinc-rich primer, nitride or hard chrome; surface can be induction hardened locally for wear zones.
G30CrMoV6-4 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 |
|---|---|---|
| Cmedium carbon for high tempered strength | 0.27 – 0.34 | 0.3 |
| Si | 0.2 – 0.6 | 0.4 |
| Mn | 0.6 – 1 | 0.8 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Cr | 1.2 – 1.7 | 1.5 |
| Mo | 0.3 – 0.55 | 0.4 |
| Vgrain refinement + secondary hardening | 0.08 – 0.15 | 0.1 |
| Niresidual | ≤ 0.4 | — |
| Fe | balance | — |
G30CrMoV6-4 +QT1 — frequently asked
What is G30CrMoV6-4 +QT1 used for?
G30CrMoV6-4 +QT1 is typically used for turbine casings, large valve bodies, gearbox and housing castings for heavy machinery and high-strength pressure vessel components. In short: strongest Cr-Mo-V cast grade; 920 MPa tensile in +QT; difficult to weld.
What is the yield strength of G30CrMoV6-4 +QT1?
G30CrMoV6-4 +QT1 has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 920 MPa (133 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is G30CrMoV6-4 +QT1 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine mostly in the annealed/normalized state; in +QT (280–350 HB) use rigid setups, coated carbide, ~80–140 m/min and positive feed to break through the cast skin.
Can G30CrMoV6-4 +QT1 be welded?
Not readily — weldability is rated poor (30/100). Weldable only with matching low-hydrogen Cr-Mo consumables, 250–350 °C preheat/interpass and 620–680 °C PWHT below the tempering temperature; upgrade/repair welds should precede final Q&T.
What surface finishes work on G30CrMoV6-4 +QT1?
No inherent corrosion resistance: shot blast, then paint, phosphate, zinc-rich primer, nitride or hard chrome; surface can be induction hardened locally for wear zones.
Can G30CrMoV6-4 +QT1 be formed, bent or molded?
Sand or investment cast with generous feeders — steel shrinkage ~2%; avoid abrupt section changes, and always normalize/homogenize before hardening to break down dendritic structure.
What is the maximum service temperature of G30CrMoV6-4 +QT1?
G30CrMoV6-4 +QT1 is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10293 — Steel castings for general engineering uses — CEN (2015)
- EN 10213 — Steel castings for pressure purposes — CEN (2016)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook — Steel Founders' Society of America / ASM (1995)
- EN ISO 18265 — Conversion of hardness values — CEN/ISO (2013)
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.