Steel 20CrNiMo
GB 20CrNiMo · JIS SNCM220
20CrNiMo is a Cr-Ni-Mo case-hardening steel equivalent to SAE 8620, JIS SNCM220 and 21NiCrMo2 (1.6523), combining moderate hardenability with a tough core after carburizing.
Reference datasheet — 20CrNiMo 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 A condition
20CrNiMo tempers and conditions
20CrNiMo is supplied in 8 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
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 |
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?
20CrNiMo is a Cr-Ni-Mo case-hardening steel equivalent to SAE 8620, JIS SNCM220 and 21NiCrMo2 (1.6523), combining moderate hardenability with a tough core after carburizing. It is the default gear steel for automotive and general machinery and is widely stocked as hot-rolled, annealed, normalized-and-tempered and cold-drawn bar and forgings. Annealed core values are about 390 MPa yield, 610 MPa tensile, 28% elongation and 175 HB, with service to roughly 400 °C. It has no corrosion resistance and must be welded before carburizing; use 20CrMnMo where more core strength is needed. 20CrNiMo 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). 20CrNiMo has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 610 MPa (88.5 ksi) — weaker than 64% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
What is 20CrNiMo used for?
- automotive gears
- shafts
- pinions
Advantages
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
20CrNiMo properties
Typical room-temperature values for 20CrNiMo-A; bars are the position among steel grades.
Physical3
20CrNiMo 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 has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 610 MPa (88.5 ksi) — weaker than 64% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20CrNiMo is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
20CrNiMo 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 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's machinability is good (58/100, better than 75% of steel grades); weldability good (55/100); formability good (55/100).
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. 20CrNiMo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20CrNiMo
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.
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 |
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.
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 20CrNiMo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 20CrNiMo cost?
20CrNiMo is a budget-cost steel ($), cheaper than about 90% 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.
20CrNiMo — frequently asked
What is 20CrNiMo used for?
20CrNiMo 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?
20CrNiMo has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 610 MPa (88.5 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 20CrNiMo easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% 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 be welded?
Yes — weldability is rated good (55/100). 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?
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 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?
20CrNiMo is rated for continuous use to about 400°C (752 °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.
How much does 20CrNiMo cost?
20CrNiMo is a budget-cost steel ($), cheaper than about 90% 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
- 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; 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.