Steel 20CrMo · heat-treated state
Steel 20CrMo Q&T
Properties of the Q&T condition, compared with the other 20CrMo tempers.
Standard high-strength condition for shafts, gears, bolts and high-pressure fittings; properties quoted on 15 mm test blank.
What is 20CrMo Q&T?
20CrMo Q&T is 20CrMo heat treated to Q&T — standard high-strength condition for shafts, gears, bolts and high-pressure fittings; properties quoted on 15 mm test blank. 20CrMo Q&T has a yield strength of 760 MPa (110 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 85% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). 20CrMo Q&T 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; Q&T is available on request or by drawing note.
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 ductility — 14%, worse than 75% of steel grades
20CrMo Q&T properties
Typical room-temperature values for 20CrMo Q&T — 16 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 Q&T 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 Q&T has a yield strength of 760 MPa (110 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 85% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20CrMo Q&T 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).
Electrical2
20CrMo Q&T 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 Q&T 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 Q&T's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (45/100); formability poor (25/100).
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 Q&T
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 Q&T — frequently asked
What is 20CrMo Q&T used for?
20CrMo Q&T 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 Q&T?
20CrMo Q&T has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20CrMo Q&T easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% 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 Q&T be welded?
With care — weldability is rated fair (45/100). 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 Q&T?
No natural corrosion resistance — specify phosphate+oil, black oxide, zinc, zinc-nickel or QPQ nitrocarburizing; takes a good polish after Q&T.
Can 20CrMo Q&T 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 Q&T?
20CrMo Q&T 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 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 Q&T?
Yes — 20CrMo Q&T 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.