Steel 20CrMo · heat-treated state
Steel 20CrMo Carburized
Properties of the Carburized condition, compared with the other 20CrMo tempers.
Use for gears, splines and pins needing a 0.6–1.2 mm hard case (58–62 HRC) on a tough Q&T core.
What is 20CrMo Carburized?
20CrMo Carburized is 20CrMo heat treated to Carburized — use for gears, splines and pins needing a 0.6–1.2 mm hard case (58–62 HRC) on a tough Q&T core. 20CrMo Carburized has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). 20CrMo Carburized has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). HR is the default condition FabDigit quotes; Carburized is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
Limitations
- Limited formability — 5/100, worse than 99% of steel grades
- Difficult to machine — 15/100, worse than 98% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
20CrMo Carburized properties
Typical room-temperature values for 20CrMo Carburized — 11 properties are specific to this condition; the rest are grade-level values shared by every 20CrMo temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
20CrMo Carburized has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical13
20CrMo Carburized has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20CrMo Carburized is rated for continuous service to 500°C (932 °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).
Electrical2
20CrMo Carburized has an electrical resistivity of 2.3×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of 20CrMo Carburized takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability7
20CrMo Carburized's machinability is poor (15/100, worse than 98% of steel grades); weldability poor (20/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 20CrMo tempers and conditions
20CrMo is also supplied in 6 other conditions. The full side-by-side table is on the 20CrMo overview.
- HRDefaultMost-stocked mill condition for bar, seamless tube and plate; machine then heat treat as required.450 MPa yield · 200 HB
- CarburizedUse for gears, splines and pins needing a 0.6–1.2 mm hard case (58–62 HRC) on a tough Q&T core.800 MPa yield · 60 HRC
- Q&TStandard high-strength condition for shafts, gears, bolts and high-pressure fittings; properties quoted on 15 mm test blank.760 MPa yield · 30 HRC
- CDPick for precision-diameter shafting and screw-machine work where higher yield and better surface are wanted without heat treatment.620 MPa yield · 230 HB
- NormalizedUniform fine grain and stable properties for weldments, pressure parts and forging stock.440 MPa yield · 195 HB
- AnnealedSoftest condition — use for deep machining, cold forming or before carburizing.350 MPa yield · 170 HB
Working with 20CrMo Carburized
Is 20CrMo easy to machine?
Machines like 4118/4130 — best in annealed or normalized state (~60 % of AISI 1212); carbide tooling, rigid setup and flood coolant above 280 HB.
Can 20CrMo be welded?
Weldable with low-hydrogen or matching Cr-Mo filler; preheat 150–250 °C for thick or Q&T parts and post-weld temper at 620–680 °C to avoid HAZ hardening/cracking.
Can 20CrMo be formed, bent or molded?
Cold form only in annealed condition with generous radii; hot forge 1150–850 °C followed by normalizing or annealing to restore grain size.
What surface finishes work on 20CrMo?
No natural corrosion resistance — specify phosphate+oil, black oxide, zinc, zinc-nickel or QPQ nitrocarburizing; takes a good polish after Q&T.
20CrMo 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 | 0.17 – 0.24 | 0.2 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.4 – 0.7 | 0.55 |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
20CrMo Carburized — frequently asked
What is 20CrMo Carburized used for?
20CrMo Carburized is typically used for carburized gears and pinions, industrial drive shafts, bolts and studs, splined couplings and yokes, camshafts and rocker pins and pump and gearbox spindles. In short: workhorse chrome-moly bar.
What is the yield strength of 20CrMo Carburized?
20CrMo Carburized has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20CrMo Carburized easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% of steel grades). Machines like 4118/4130 — best in annealed or normalized state (~60 % of AISI 1212); carbide tooling, rigid setup and flood coolant above 280 HB.
Can 20CrMo Carburized be welded?
Not readily — weldability is rated poor (20/100). Weldable with low-hydrogen or matching Cr-Mo filler; preheat 150–250 °C for thick or Q&T parts and post-weld temper at 620–680 °C to avoid HAZ hardening/cracking.
What surface finishes work on 20CrMo Carburized?
No natural corrosion resistance — specify phosphate+oil, black oxide, zinc, zinc-nickel or QPQ nitrocarburizing; takes a good polish after Q&T.
Can 20CrMo Carburized be formed, bent or molded?
Cold form only in annealed condition with generous radii; hot forge 1150–850 °C followed by normalizing or annealing to restore grain size.
What is the maximum service temperature of 20CrMo Carburized?
20CrMo Carburized is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20CrMo-HR and 20CrMo-CD?
HR is the default condition — most-stocked mill condition for bar, seamless tube and plate; machine then heat treat as required. CD: pick for precision-diameter shafting and screw-machine work where higher yield and better surface are wanted without heat treatment. Yield strength is 450 MPa in HR versus 620 MPa in CD.
Can FabDigit make parts in 20CrMo Carburized?
Yes — 20CrMo Carburized is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 3077 Alloy structural steels — SAC (China) (2015)
- GB/T 8162 Seamless steel tubes for structural purposes — SAC (China) (2018)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating — ASM International (1991)
- Chinese alloy structural steel property tables (20CrMo / 4118 equivalence) (2016)
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.