Steel 20NiCrMo7
EN 20NiCrMo7
20NiCrMo7 (1.3576; AISI 8620) is a nickel-chromium-molybdenum case-hardening steel of the EN 10084 family, where nickel provides deep hardenability and high core toughness.
Reference datasheet — 20NiCrMo7 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
20NiCrMo7 tempers and conditions
20NiCrMo7 is supplied in 10 conditions, soft to hard. +A is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold extrusion, cold heading or deep-drawing blanks where maximum ductility and minimum flow stress are required. | 360 | 560 | 24 | 165 HB | — |
Treated for high shearability | Use for coil and bar that will be cold sheared into cold-forging slugs without cracked or dished cut faces. | 390 | 600 | 21 | 178 HB | 8 % IACS |
+ADefault Annealed | Standard stock condition for bar and forging stock: softest state for general machining before carburizing. | 400 | 620 | 20 | 190 HB | — |
Annealed to a ferrite–pearlite structure with specified hardness range | Pick when a uniform ferrite-pearlite microstructure and a narrow hardness band are needed for consistent automatic-lathe machining and predictable distortion. | 420 | 640 | 18 | 185 HB | — |
Supplied with guaranteed hardenability band | Specify for gears and bearing rings where the carburizing shop needs a guaranteed Jominy band so case/core hardness after quench is reproducible. | 420 | 640 | 18 | 43 HRC | 8 % IACS |
Heat treated to a specified hardness range | Order when the mill must guarantee a narrow as-delivered hardness band for machining productivity and tool-life consistency. | 440 | 660 | 17 | 13 HRC | 8 % IACS |
Normalized | Used on forgings to refine and homogenize grain before machining and carburizing; slightly stronger and harder than +A. | 500 | 750 | 16 | 20 HRC | 8 % IACS |
Cold drawn | Cold-drawn bright bar for close tolerance and good surface on turned parts; higher strength but residual stress can cause distortion in carburizing. | 580 | 720 | 12 | 220 HB | 8 % IACS |
quenched and tempered (through-hardened core condition, ~300 HB) | For uncarburized shafts and fasteners made from this grade where a tough, high-strength core alone is sufficient. | 800 | 1,000 | 13 | 31 HRC | — |
Carburized and hardened | The service condition for gears and bearing rings: hard wear-resistant case with compressive residual stress over a tough 350–450 HV core. | 950 | 1,250 | 10 | 60 HRC | 40 W/m·K |
What is 20NiCrMo7?
20NiCrMo7 (1.3576; AISI 8620) is a nickel-chromium-molybdenum case-hardening steel of the EN 10084 family, where nickel provides deep hardenability and high core toughness. It is widely available as bar, tube and forging stock in annealed, ferrite-pearlite, spheroidized, normalized and treated-for-machining conditions; soft default values are 400 MPa yield, 620 MPa tensile, 20% elongation and 190 HB (91 HRB), with service to 350 °C. It costs more than 20CrMo4, machines gummy because of the tough Ni-bearing matrix, and welding demands preheat plus stress relief. 20NiCrMo7 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). 20NiCrMo7 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
What is 20NiCrMo7 used for?
- gears
- bearings
- aerospace shafts
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
20NiCrMo7 properties
Typical room-temperature values for 20NiCrMo7-+A; bars are the position among steel grades.
Physical3
20NiCrMo7 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
20NiCrMo7 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20NiCrMo7 is rated for continuous service to 350°C (662 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
20NiCrMo7 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 20NiCrMo7 takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
20NiCrMo7's machinability is good (55/100, better than 62% of steel grades); weldability fair (45/100); 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. 20NiCrMo7 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20NiCrMo7
Is 20NiCrMo7 easy to machine?
Machine in the +A/+FP/+TH soft condition with carbide at moderate speed and generous feed; the tough Ni-bearing matrix is gummy, so use sharp positive geometry and high-pressure coolant, and finish-grind after carburizing.
Can 20NiCrMo7 be welded?
Weldable with low-hydrogen consumables at 200–300 °C preheat plus immediate stress relief; never weld through a carburized case, and avoid welding parts already hardened.
Can 20NiCrMo7 be formed, bent or molded?
Hot forge 1100–1150 °C with slow cooling and normalize afterwards; cold heading and extrusion only in the +AC (spheroidized) or +S condition.
20NiCrMo7 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 |
| SiSi ≤ 0.40 (bearing-steel practice often ≤0.35) | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.03 | |
| S≤0.015 for bearing quality per EN ISO 683-17 | ≤ 0.04 | |
| Cr | 0.35 – 0.65 | 0.5 |
| Ni | 1.6 – 2 | 1.8 |
| Mo | 0.2 – 0.3 | 0.25 |
| Curesidual | ≤ 0.3 | |
| Fe | balance |
What surface finishes work on 20NiCrMo7?
Case-hardened surfaces are hard ground and honed; unhardened areas are protected by black oxide, phosphate, zinc or oil — bake plated parts at 190 °C to relieve hydrogen.
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 20NiCrMo7 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 20NiCrMo7 cost?
20NiCrMo7 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.
20NiCrMo7 — frequently asked
What is 20NiCrMo7 used for?
20NiCrMo7 is typically used for gears, bearings and aerospace shafts. In short: 8620 equivalent case-hardening steel; deep hardenability, tough core; higher alloy cost.
What is the yield strength of 20NiCrMo7?
20NiCrMo7 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 20NiCrMo7 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the +A/+FP/+TH soft condition with carbide at moderate speed and generous feed; the tough Ni-bearing matrix is gummy, so use sharp positive geometry and high-pressure coolant, and finish-grind after carburizing.
Can 20NiCrMo7 be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen consumables at 200–300 °C preheat plus immediate stress relief; never weld through a carburized case, and avoid welding parts already hardened.
What surface finishes work on 20NiCrMo7?
Case-hardened surfaces are hard ground and honed; unhardened areas are protected by black oxide, phosphate, zinc or oil — bake plated parts at 190 °C to relieve hydrogen.
Can 20NiCrMo7 be formed, bent or molded?
Hot forge 1100–1150 °C with slow cooling and normalize afterwards; cold heading and extrusion only in the +AC (spheroidized) or +S condition.
What is the maximum service temperature of 20NiCrMo7?
20NiCrMo7 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20NiCrMo7 +A and 20NiCrMo7-CH?
+A is the default condition — standard stock condition for bar and forging stock: softest state for general machining before carburizing. CH: the service condition for gears and bearing rings: hard wear-resistant case with compressive residual stress over a tough 350–450 HV core. Yield strength is 400 MPa in +A versus 950 MPa in CH.
How much does 20NiCrMo7 cost?
20NiCrMo7 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 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN ISO 683-17 — Heat-treatable steels, alloy steels: ball and roller bearing steels — ISO (2014)
- GB/T 3077 — Alloy structural steels (20CrNiMo) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals and Processes (carburizing) — ASM International (2013)
- Case-hardening / bearing steel bar datasheets (Ovako, Ascometal, Böhler) — various producers (2023)
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.