Steel G42CrMo4 +QT2
Heat-treated state
EN 1.7231 · GB ZG42CrMo
+QT2 = quenched and tempered, higher strength class
Choose when 700 MPa-class yield strength is required and section sizes are moderate; toughness and weld repairability drop.
Values for the +QT2 condition
Other G42CrMo4 tempers and conditions
G42CrMo4 is listed in 4 conditions; see the grade overview at G42CrMo4.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for rough-machining or when the casting will be heat treated after machining. | 380 | 640 | 20 | 195 HB | — |
Normalized | Intermediate strength with uniform structure in very heavy sections where through-quenching is impractical. | 450 | 700 | 16 | 18 HRC | 7.8 % IACS |
+QT1Default Quenched and tempered, lower strength class | Standard stocked condition: best balance of 500 MPa-class yield strength and impact toughness for general machinery castings. | 540 | 780 | 14 | 21 HRC | — |
+QT2This page Quenched and tempered, higher strength class | Choose when 700 MPa-class yield strength is required and section sizes are moderate; toughness and weld repairability drop. | 740 | 920 | 11 | 29 HRC | — |
What is G42CrMo4 +QT2?
G42CrMo4 +QT2 is G42CrMo4 heat treated to +QT2 — choose when 700 MPa-class yield strength is required and section sizes are moderate; toughness and weld repairability drop. G42CrMo4 +QT2 has a yield strength of 740 MPa (107 ksi) and a tensile strength of 920 MPa (133 ksi) — stronger than 83% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). G42CrMo4 +QT2 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). +QT1 is the default condition FabDigit quotes; +QT2 is available on request or by drawing note.
Advantages
- High strength — 740 MPa (107 ksi), better than 83% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
G42CrMo4 +QT2 properties
Typical room-temperature values for G42CrMo4 +QT2; 18 are specific to this condition. Other listed values are G42CrMo4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G42CrMo4 +QT2 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
G42CrMo4 +QT2 has a yield strength of 740 MPa (107 ksi) and a tensile strength of 920 MPa (133 ksi) — stronger than 83% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G42CrMo4 +QT2 is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
G42CrMo4 +QT2 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of G42CrMo4 +QT2 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 80%.
Manufacturability8
G42CrMo4 +QT2's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (28/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G42CrMo4 +QT2
Is G42CrMo4 easy to machine?
Machine in the annealed state where possible; at 250–300 HB use rigid setups, coated carbide, moderate speed and heavy positive feed to break through the cast skin and any residual scale.
Can G42CrMo4 be welded?
Weldable only with care: preheat 250–350 °C, low-hydrogen or matching Cr-Mo consumables, controlled interpass temperature and a post-weld temper below the original tempering temperature; foundry weld repair is normally done before final heat treatment.
Can G42CrMo4 be formed, bent or molded?
Sand or investment cast with generous risering and directional solidification; avoid abrupt section changes, and stress-relieve before final heat treatment to limit distortion and quench cracking.
What surface finishes work on G42CrMo4?
No anodizing — protect with paint, phosphate, black oxide, zinc or hard chrome; induction or nitride hardening of journals is common on Q&T castings.
G42CrMo4 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 10293 cast analysis | 0.38 – 0.45 | 0.42 |
| Si | ≤ 0.6 | 0.4 |
| Mn | 0.6 – 1 | 0.8 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Cr | 0.8 – 1.2 | 1 |
| Mo | 0.15 – 0.3 | 0.22 |
| Niresidual | ≤ 0.4 | — |
| Fe | balance | — |
G42CrMo4 +QT2 — frequently asked
What is G42CrMo4 +QT2 used for?
G42CrMo4 +QT2 is typically used for gear and shaft castings, high-strength machinery components and heavy structural castings. In short: cast 4140 equivalent; highest strength cast CrMo; hardenable to 250–300 HB.
What is the yield strength of G42CrMo4 +QT2?
G42CrMo4 +QT2 has a typical yield strength of 740 MPa (107 ksi) and a tensile strength of 920 MPa (133 ksi) — stronger than 83% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is G42CrMo4 +QT2 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in the annealed state where possible; at 250–300 HB use rigid setups, coated carbide, moderate speed and heavy positive feed to break through the cast skin and any residual scale.
Can G42CrMo4 +QT2 be welded?
Not readily — weldability is rated poor (28/100). Weldable only with care: preheat 250–350 °C, low-hydrogen or matching Cr-Mo consumables, controlled interpass temperature and a post-weld temper below the original tempering temperature; foundry weld repair is normally done before final heat treatment.
What surface finishes work on G42CrMo4 +QT2?
No anodizing — protect with paint, phosphate, black oxide, zinc or hard chrome; induction or nitride hardening of journals is common on Q&T castings.
Can G42CrMo4 +QT2 be formed, bent or molded?
Sand or investment cast with generous risering and directional solidification; avoid abrupt section changes, and stress-relieve before final heat treatment to limit distortion and quench cracking.
What is the maximum service temperature of G42CrMo4 +QT2?
G42CrMo4 +QT2 is rated for continuous use to about 400°C (752 °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 10340 — Steel castings for structural uses — CEN (2007)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- Machinery's Handbook (machinability ratings) — Industrial Press (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.