Steel GS-42CrMo4
AISI/SAE 4140 · EN 1.7231 · GB ZG42CrMo
GS-42CrMo4 (1.7231, ZG42CrMo) is the cast counterpart of wrought 42CrMo4/4140, a Cr-Mo low-alloy steel hardened by quenching and tempering.
Reference datasheet — GS-42CrMo4 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 +QT condition
GS-42CrMo4 tempers and conditions
GS-42CrMo4 is supplied in 9 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum machinability of rough castings before final Q&T. | 390 | 660 | 16 | 200 HB | — |
Normalized | Refines the as-cast dendritic structure and gives uniform medium strength for lightly loaded castings. | 470 | 780 | 13 | 19 HRC | 8 % IACS |
As fabricated | Raw casting condition, only for non-critical parts or as the starting point before annealing/Q&T. | 480 | 800 | 8 | 24 HRC | 8 % IACS |
Normalized and tempered | Use for large-section castings where full quenching is impractical but stable strength and toughness are needed. | 540 | 820 | 13 | 22 HRC | 7.9 % IACS |
Stress relieved | Sub-critical treatment (typically below the tempering temperature) to relieve casting/weld-repair stresses without changing strength much. | 740 | 960 | 12 | 28 HRC | 7.8 % IACS |
+QTDefault Quenched and tempered | Standard supply condition: best strength/toughness balance for gears, housings and heavily loaded machine castings. | 760 | 980 | 11 | 29 HRC | — |
+QT + flame/induction hardened surface | Q&T core with a hardened running surface — for cast gear teeth, tracks and journals needing wear resistance. | 760 | 980 | 10 | 54 HRC | 7.5 % IACS |
tempered to medium hardness | Common ordered hardness band for shafts, hubs and gear blanks that must still be machined after heat treatment. | 800 | 1,000 | 11 | 30 HRC | — |
tempered to high hardness | Choose when wear resistance and high yield strength dominate and reduced impact toughness is acceptable. | 950 | 1,150 | 8 | 36 HRC | — |
What is GS-42CrMo4?
GS-42CrMo4 (1.7231, ZG42CrMo) is the cast counterpart of wrought 42CrMo4/4140, a Cr-Mo low-alloy steel hardened by quenching and tempering. Engineers use it for heavy machine castings that need 760 MPa yield, 980 MPa tensile, 11% elongation and 285 HB (29 HRC) with service to 450 °C, with tempers on file from 28-32 HRC to 34-38 HRC plus flame-hardened and stress-relieved conditions. Weldability is limited (score 35) and machinability is 45, so preheat, PWHT and rigid setups are required. Where welding dominates the build, G10MnMoV6-3 is easier to join. GS-42CrMo4 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). GS-42CrMo4 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 85% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
What is GS-42CrMo4 used for?
- gear housings
- heavy machinery parts
- crankshaft supports
- couplings
Advantages
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
GS-42CrMo4 properties
Typical room-temperature values for GS-42CrMo4-+QT; bars are the position among steel grades.
Physical3
GS-42CrMo4 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
GS-42CrMo4 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 85% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
GS-42CrMo4 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
GS-42CrMo4 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of GS-42CrMo4 takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 80%.
Manufacturability7
GS-42CrMo4's machinability is fair (45/100, worse than 65% 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. GS-42CrMo4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GS-42CrMo4
Is GS-42CrMo4 easy to machine?
Rough-machine in the annealed state (≈200 HB); at 280–330 HB use rigid setups, coated carbide, ~90–140 m/min and positive rake to control work hardening in casting skin.
Can GS-42CrMo4 be welded?
Weldable with low-hydrogen electrodes matching Cr-Mo composition; preheat 250–350 °C, keep interpass temperature and apply PWHT/temper at 600–680 °C to avoid cold cracking.
Can GS-42CrMo4 be formed, bent or molded?
Sand or investment cast with generous risering and controlled solidification; hot-tear prone at section changes — use fillets, chills and homogenize/normalize before final Q&T.
GS-42CrMo4 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 |
|---|---|---|
| C | 0.38 – 0.45 | 0.42 |
| Si≤0.60 % | ≤ 0.6 | 0.4 |
| Mn | 0.6 – 1 | 0.8 |
| PEN 10293 casting limit | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Niresidual | ≤ 0.4 | 0.15 |
| Fe | balance |
What surface finishes work on GS-42CrMo4?
No natural corrosion resistance: shot-blast then paint, phosphate, zinc-rich primer, or hard-chrome/nitride the wear surfaces; polishes reasonably well after Q&T.
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 GS-42CrMo4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does GS-42CrMo4 cost?
GS-42CrMo4 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.
GS-42CrMo4 — frequently asked
What is GS-42CrMo4 used for?
GS-42CrMo4 is typically used for gear housings, heavy machinery parts, crankshaft supports and couplings. In short: cast 4140 equivalent; high-strength Cr-Mo casting; needs preheat and PWHT.
What is the yield strength of GS-42CrMo4?
GS-42CrMo4 has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is GS-42CrMo4 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Rough-machine in the annealed state (≈200 HB); at 280–330 HB use rigid setups, coated carbide, ~90–140 m/min and positive rake to control work hardening in casting skin.
Can GS-42CrMo4 be welded?
With care — weldability is rated fair (35/100). Weldable with low-hydrogen electrodes matching Cr-Mo composition; preheat 250–350 °C, keep interpass temperature and apply PWHT/temper at 600–680 °C to avoid cold cracking.
What surface finishes work on GS-42CrMo4?
No natural corrosion resistance: shot-blast then paint, phosphate, zinc-rich primer, or hard-chrome/nitride the wear surfaces; polishes reasonably well after Q&T.
Can GS-42CrMo4 be formed, bent or molded?
Sand or investment cast with generous risering and controlled solidification; hot-tear prone at section changes — use fillets, chills and homogenize/normalize before final Q&T.
What is the maximum service temperature of GS-42CrMo4?
GS-42CrMo4 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.
What is the difference between GS-42CrMo4 +QT and GS-42CrMo4-F?
+QT is the default condition — standard supply condition: best strength/toughness balance for gears, housings and heavily loaded machine castings. F: raw casting condition, only for non-critical parts or as the starting point before annealing/Q&T. Yield strength is 760 MPa in +QT versus 480 MPa in F.
How much does GS-42CrMo4 cost?
GS-42CrMo4 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 (G42CrMo4, 1.7231) — CEN (2015)
- DIN 17205 — Quenched and tempered steel castings for general purposes — DIN (1992)
- GB/T 14408 — General purpose low-alloy steel castings (ZG42CrMo) — SAC (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- SEW 685 / Stahlschlüssel data for 42CrMo4 — Verlag Stahlschlüssel (2019)
- ZG42CrMo 1688 / Mysteel — Mysteel / 1688 (2025)
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.