Steel 20CrNiMo CHQT
Heat-treated state
GB 20CrNiMo · JIS SNCM220
CHQT = carburized, quenched and low tempered
The end-use gear condition: hard wear-resistant case with high bending fatigue over a tough core.
Values for the CHQT condition
Other 20CrNiMo tempers and conditions
20CrNiMo is listed in 8 conditions; see the grade overview at 20CrNiMo.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked bar condition: softest state for turning, hobbing and cold working before carburizing. | 390 | 610 | 28 | 175 HB | — |
Normalized and high-temperature tempered | Preferred pre-heat-treatment for gear blanks: stable hardness 179–217 HB with low residual stress. | 430 | 670 | 25 | 14 HRC | 8 % IACS |
Hot rolled | Cheapest stock condition for forging or blanks that will be normalized/carburized later. | 450 | 700 | 20 | 14 HRC | 8 % IACS |
Normalized | Use to refine forging grain and get uniform machining response before carburizing. | 450 | 700 | 24 | 11 HRC | 8 % IACS |
Cold drawn | Choose for tight-tolerance bright bar and automatic-lathe parts made near-net before case hardening. | 640 | 780 | 12 | 18 HRC | 8 % IACS |
quenched and tempered to medium hardness | For shafts and non-carburized machine parts where toughness and machinability after heat treatment matter. | 780 | 950 | 16 | 30 HRC | — |
Q&T 200 °C | The specification acceptance condition; also used for small direct-hardened parts needing high strength without carburizing. | 880 | 1,080 | 12 | 36 HRC | 40 W/m·K |
CHQTThis page Carburized, quenched and low tempered | The end-use gear condition: hard wear-resistant case with high bending fatigue over a tough core. | 950 | 1,200 | 10 | 60 HRC | 38 W/m·K |
What is 20CrNiMo CHQT?
20CrNiMo CHQT is 20CrNiMo heat treated to CHQT — the end-use gear condition: hard wear-resistant case with high bending fatigue over a tough core. 20CrNiMo CHQT has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 91% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi). 20CrNiMo CHQT 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). A is the default condition FabDigit quotes; CHQT is available on request or by drawing note.
Advantages
- High strength — 950 MPa (138 ksi), better than 91% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Low fracture toughness — 30 MPa·√m (27.3 ksi·√in), worse than 96% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
20CrNiMo CHQT properties
Typical room-temperature values for 20CrNiMo CHQT; 15 are specific to this condition. Other listed values are 20CrNiMo reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20CrNiMo CHQT 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).
Mechanical16
20CrNiMo CHQT has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 91% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20CrNiMo CHQT is rated for continuous service to 180°C (356 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
20CrNiMo CHQT conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20CrNiMo CHQT takes about 33 MJ of energy and emits 2.2 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 25%.
Manufacturability7
20CrNiMo CHQT's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (10/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20CrNiMo CHQT
Is 20CrNiMo easy to machine?
Machine in the annealed or normalized+tempered state (≈180–210 HB) with carbide tooling; leave grinding stock because carburizing distorts and the finished case is only grindable.
Can 20CrNiMo be welded?
Weldable before carburizing with low-hydrogen consumables, 150–250 °C preheat and post-weld stress relief; welding a carburized surface is not recommended.
Can 20CrNiMo be formed, bent or molded?
Hot forge at 1150–1200 °C, finish above 850 °C and normalize afterwards; cold heading and cold extrusion possible after spheroidize annealing.
What surface finishes work on 20CrNiMo?
No anodizing — protect with phosphate + oil, black oxide, zinc or Zn-Ni plating; shot peening after carburizing markedly raises gear-tooth bending fatigue.
20CrNiMo 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 – 0.23 | 0.2 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.6 – 0.95 | 0.78 |
| Cr | 0.4 – 0.7 | 0.55 |
| Ni | 0.35 – 0.75 | 0.55 |
| Mo | 0.15 – 0.25 | 0.2 |
| Pmax; ≤0.025 for high-grade quality | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Curesidual, max | ≤ 0.3 | — |
| Fe | balance | — |
20CrNiMo CHQT — frequently asked
What is 20CrNiMo CHQT used for?
20CrNiMo CHQT is typically used for automotive gears, shafts and pinions. In short: 8620-equivalent gear steel; best all-round carburizing grade; weldable before carburizing.
What is the yield strength of 20CrNiMo CHQT?
20CrNiMo CHQT has a typical yield strength of 950 MPa (138 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 20CrNiMo CHQT easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed or normalized+tempered state (≈180–210 HB) with carbide tooling; leave grinding stock because carburizing distorts and the finished case is only grindable.
Can 20CrNiMo CHQT be welded?
Not readily — weldability is rated not recommended (10/100). Weldable before carburizing with low-hydrogen consumables, 150–250 °C preheat and post-weld stress relief; welding a carburized surface is not recommended.
What surface finishes work on 20CrNiMo CHQT?
No anodizing — protect with phosphate + oil, black oxide, zinc or Zn-Ni plating; shot peening after carburizing markedly raises gear-tooth bending fatigue.
Can 20CrNiMo CHQT be formed, bent or molded?
Hot forge at 1150–1200 °C, finish above 850 °C and normalize afterwards; cold heading and cold extrusion possible after spheroidize annealing.
What is the maximum service temperature of 20CrNiMo CHQT?
20CrNiMo CHQT is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20CrNiMo-A and 20CrNiMo CHQT?
A is the default condition — standard stocked bar condition: softest state for turning, hobbing and cold working before carburizing. CHQT: the end-use gear condition: hard wear-resistant case with high bending fatigue over a tough core. Yield strength is 390 MPa in A versus 950 MPa in CHQT.
Sources
- SAE J404 Chemical Compositions of SAE Alloy Steels (8620) — SAE International (2021)
- EN 10084 Case hardening steels (21NiCrMo2, 1.6523) — CEN (2008)
- JIS G 4053 (SNCM220) — JSA (2016)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating (Carburizing) — ASM International (1991)
- Machinery's Handbook, 31st ed. — 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.