Steel 20NiCrMoS6-4
EN 20NiCrMoS6-4
20NiCrMoS6-4 (1.6571) is a resulfurized Ni-Cr-Mo case-hardening steel from the EN 10084 family, the free-machining version of the 17NiCrMo6-4 type, with about 0.03 % sulfur added to break chips.
Reference datasheet — 20NiCrMoS6-4 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 +FP condition
20NiCrMoS6-4 tempers and conditions
20NiCrMoS6-4 is supplied in 7 conditions, soft to hard. +FP is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Pick for deep drilling, broaching, thread rolling or cold upsetting where the lowest hardness and spheroidal carbides are wanted. | 360 | 600 | 22 | 175 HB | — |
+FPDefault Treated to ferrite-pearlite structure and hardness range | Standard gear-blank delivery: uniform ferrite-pearlite microstructure ≤217 HB giving repeatable turning/hobbing and low distortion in carburizing. | 420 | 680 | 18 | 200 HB | — |
Treated to hardness range | Ordered when only a guaranteed hardness band (not a specified microstructure) is needed for machining consistency. | 440 | 700 | 16 | 15 HRC | 7.5 % IACS |
Hot rolled | Cheapest bar delivery when the user will do their own normalize/anneal before machining. | 480 | 780 | 14 | 22 HRC | 7.5 % IACS |
Spheroidized annealed and cold drawn | Precision-ground/drawn bar for automatic lathes: tight tolerance, bright surface and higher yield strength before carburizing. | 620 | 760 | 10 | 225 HB | — |
Hardened | Use when the part is quenched (with Jominy-controlled hardenability) and low-temperature tempered to develop a strong, tough core. | 900 | 1,180 | 11 | 37 HRC | — |
Case hardened | Final in-service condition for gears and pinions: hard wear-resistant case with compressive residual stress over a tough Ni-Cr-Mo core. | 950 | 1,250 | 10 | 60 HRC | — |
What is 20NiCrMoS6-4?
20NiCrMoS6-4 (1.6571) is a resulfurized Ni-Cr-Mo case-hardening steel from the EN 10084 family, the free-machining version of the 17NiCrMo6-4 type, with about 0.03 % sulfur added to break chips. Engineers select it for carburized gears: the core reaches roughly 420 MPa yield, 680 MPa tensile, 18 % elongation and 200 HB, while the carburized case is specified at 58-62 HRC, and it is supplied as bar and forging stock. Limits are a maximum service temperature near 200 °C, only conditional weldability (score 40) and reduced transverse toughness and cold formability from the sulfide stringers; use S-free 17NiCrMo6-4 where welding or maximum toughness is required. 20NiCrMoS6-4 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). 20NiCrMoS6-4 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 53% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
What is 20NiCrMoS6-4 used for?
- Carburized transmission gears
- Automotive gearbox shafts
- Differential pinions and ring gear blanks
- Splined drive shafts
- Planetary carriers and pinion pins
- Hobbed sprockets and gear couplings
- High-volume turned case-hardened bushings
Advantages
- Easy to machine — 62/100, better than 89% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
20NiCrMoS6-4 properties
Typical room-temperature values for 20NiCrMoS6-4-+FP; bars are the position among steel grades.
Physical3
20NiCrMoS6-4 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
20NiCrMoS6-4 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 53% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20NiCrMoS6-4 is rated for continuous service to 200°C (392 °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).
Electrical3
20NiCrMoS6-4 conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20NiCrMoS6-4 takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability8
20NiCrMoS6-4's machinability is good (62/100, better than 89% of steel grades); weldability fair (40/100); formability fair (45/100).
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. 20NiCrMoS6-4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20NiCrMoS6-4
Is 20NiCrMoS6-4 easy to machine?
Best turned/hobbed in +FP or +AC at 170–217 HB; the 0.03 % S gives short chips and 10–20 % longer tool life than S-free 17NiCrMo6-4 — use coated carbide, 120–200 m/min dry or with MQL.
Can 20NiCrMoS6-4 be welded?
Only conditionally weldable: preheat 200–250 °C, low-hydrogen or matching Ni-Cr-Mo filler, slow cool and temper immediately; the sulfur raises hot-cracking risk, so avoid welding carburized zones entirely.
Can 20NiCrMoS6-4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize/soft anneal; cold heading and thread rolling only from the +AC spheroidized condition — cold formability is reduced by MnS stringers, especially transverse.
20NiCrMoS6-4 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 | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | 0.02 |
| Sdeliberate S addition for machinability (S-grade) | 0.02 – 0.04 | 0.03 |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| Ni | 1.4 – 1.7 | 1.55 |
| Fe | balance |
What surface finishes work on 20NiCrMoS6-4?
Not anodizable; after carburizing use shot peening for bending fatigue, then oil, phosphate, black oxide or Zn-Ni plate (bake to avoid hydrogen embrittlement) for corrosion protection.
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 20NiCrMoS6-4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.6571
How much does 20NiCrMoS6-4 cost?
20NiCrMoS6-4 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.
20NiCrMoS6-4 — frequently asked
What is 20NiCrMoS6-4 used for?
20NiCrMoS6-4 is typically used for carburized transmission gears, automotive gearbox shafts, differential pinions and ring gear blanks, splined drive shafts, planetary carriers and pinion pins and hobbed sprockets and gear couplings. In short: free-machining case-hardening steel; 58-62 HRC carburized case; tough Ni-Cr-Mo gear core.
What is the yield strength of 20NiCrMoS6-4?
20NiCrMoS6-4 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20NiCrMoS6-4 easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Best turned/hobbed in +FP or +AC at 170–217 HB; the 0.03 % S gives short chips and 10–20 % longer tool life than S-free 17NiCrMo6-4 — use coated carbide, 120–200 m/min dry or with MQL.
Can 20NiCrMoS6-4 be welded?
With care — weldability is rated fair (40/100). Only conditionally weldable: preheat 200–250 °C, low-hydrogen or matching Ni-Cr-Mo filler, slow cool and temper immediately; the sulfur raises hot-cracking risk, so avoid welding carburized zones entirely.
What surface finishes work on 20NiCrMoS6-4?
Not anodizable; after carburizing use shot peening for bending fatigue, then oil, phosphate, black oxide or Zn-Ni plate (bake to avoid hydrogen embrittlement) for corrosion protection.
Can 20NiCrMoS6-4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize/soft anneal; cold heading and thread rolling only from the +AC spheroidized condition — cold formability is reduced by MnS stringers, especially transverse.
What is the maximum service temperature of 20NiCrMoS6-4?
20NiCrMoS6-4 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 20NiCrMoS6-4 cost?
20NiCrMoS6-4 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
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10277 — Bright steel products: technical delivery conditions — CEN (2018)
- 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 steel bar datasheets (Ni-Cr-Mo gear steels) — Ovako / Böhler / Swiss Steel (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.