Steel G42CrMo4
EN 1.7231 · GB ZG42CrMo
G42CrMo4 (1.7231, ZG42CrMo) is the cast counterpart of the 4140/42CrMo4 chromium-molybdenum alloy family, supplied in +A, +N, +QT1 and +QT2 conditions.
Reference datasheet — G42CrMo4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +QT1 condition
G42CrMo4 tempers and conditions
G42CrMo4 is supplied in 4 conditions, soft to hard. +QT1 is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
G42CrMo4 (1.7231, ZG42CrMo) is the cast counterpart of the 4140/42CrMo4 chromium-molybdenum alloy family, supplied in +A, +N, +QT1 and +QT2 conditions. It is used for quench-and-tempered structural and machinery castings, with default values of 540 MPa yield, 780 MPa tensile, 14 % elongation and 235 HB (21 HRC) and service to 450 °C. Weldability is the main limit (score 35): preheat 250–350 °C and post-weld temper are mandatory, and repairs are best done before final heat treatment. Corrosion resistance is minimal (score 15), so coating or plating is required; G34CrMo4 is the more weld-friendly alternative. G42CrMo4 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). G42CrMo4 has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 70% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
What is G42CrMo4 used for?
- gear and shaft castings
- high-strength machinery components
- heavy structural castings
Advantages
- High service temperature — 450°C (842 °F), better than 86% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
G42CrMo4 properties
Typical room-temperature values for G42CrMo4-+QT1; bars are the position among steel grades.
Physical3
G42CrMo4 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 has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 70% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G42CrMo4 is rated for continuous service to 450°C (842 °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 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 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's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (35/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. G42CrMo4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with G42CrMo4
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel G42CrMo4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does G42CrMo4 cost?
G42CrMo4 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
G42CrMo4 — frequently asked
What is G42CrMo4 used for?
G42CrMo4 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?
G42CrMo4 has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is G42CrMo4 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% 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 be welded?
With care — weldability is rated fair (35/100). 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?
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 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?
G42CrMo4 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.
How much does G42CrMo4 cost?
G42CrMo4 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.