Steel 20MnCr5 · heat-treated state
Steel 20MnCr5-CH
Properties of the CH condition, compared with the other 20MnCr5 tempers.
The service condition for gears: 58–62 HRC case over a tough 30–40 HRC core, high contact and bending fatigue strength.
What is 20MnCr5-CH?
20MnCr5-CH is 20MnCr5 heat treated to CH — the service condition for gears: 58–62 HRC case over a tough 30–40 HRC core, high contact and bending fatigue strength. 20MnCr5-CH has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). 20MnCr5-CH 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; CH is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 75/100, better than 94% of steel grades
- High strength — 780 MPa (113 ksi), better than 86% of steel grades
Limitations
- Difficult to machine — 10/100, worse than 100% of steel grades
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
20MnCr5-CH properties
Typical room-temperature values for 20MnCr5-CH — 12 properties are specific to this condition; the rest are grade-level values shared by every 20MnCr5 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
20MnCr5-CH 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).
Mechanical15
20MnCr5-CH has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20MnCr5-CH is rated for continuous service to 150°C (302 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.1 µm/m·K (6.17 µin/in·°F).
Electrical3
20MnCr5-CH conducts electricity at 8.2 % IACS, better than 60% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of 20MnCr5-CH takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability8
20MnCr5-CH's machinability is not recommended (10/100, worse than 100% of steel grades); weldability not recommended (5/100); formability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 20MnCr5 tempers and conditions
20MnCr5 is also supplied in 7 other conditions. The full side-by-side table is on the 20MnCr5 overview.
- HRDefaultStandard stock condition for gear blanks that will be machined then carburized.460 MPa yield · 210 HB
- CHThe service condition for gears: 58–62 HRC case over a tough 30–40 HRC core, high contact and bending fatigue strength.780 MPa yield · 60 HRC
- Q&TThrough-hardened core condition (no carburizing) for medium-strength shafts; core values per EN 10084 for 11–30 mm sections.750 MPa yield · 32 HRC
- CDBright, size-accurate bar for automatic-lathe parts and shafts; higher strength, lower ductility.620 MPa yield · 230 HB
- NormalizedUniform fine ferrite–pearlite structure before machining and carburizing; reduces distortion scatter.420 MPa yield · 190 HB
- AnnealedSoftest condition, max hardness 217 HB — choose for heavy machining or cold forging of blanks.350 MPa yield · 170 HB
Working with 20MnCr5-CH
Is 20MnCr5 easy to machine?
Machine in the annealed or normalized state with carbide tooling (≈60% of 1212); finish-grind after carburizing since 60 HRC case is essentially unmachinable.
Can 20MnCr5 be welded?
Weldable only before carburizing — preheat 200–250 °C, low-hydrogen consumables, post-weld stress relief; never weld a case-hardened surface.
Can 20MnCr5 be formed, bent or molded?
Good hot forgeability at 1100–1200 °C and good cold-heading behaviour after spheroidize annealing; normalize after forging before machining.
What surface finishes work on 20MnCr5?
No anodizing; protect with oil, black oxide, Mn-phosphate or zinc plating (bake for hydrogen relief), and shot-peen gear roots to boost bending fatigue.
20MnCr5 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 |
|---|---|---|
| CEN 10084 | 0.17 – 0.22 | 0.2 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 1.1 – 1.4 | 1.25 |
| Cr | 1 – 1.3 | 1.15 |
| P | ≤ 0.03 | 0.02 |
| S0.020–0.040 for the +S free-machining variant | ≤ 0.04 | 0.02 |
| Fe | balance | — |
20MnCr5-CH — frequently asked
What is 20MnCr5-CH used for?
20MnCr5-CH is typically used for gears, industrial drive shafts and pins. In short: carburizing Cr-Mn bar.
What is the yield strength of 20MnCr5-CH?
20MnCr5-CH has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 20MnCr5-CH easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 100% of steel grades). Machine in the annealed or normalized state with carbide tooling (≈60% of 1212); finish-grind after carburizing since 60 HRC case is essentially unmachinable.
Can 20MnCr5-CH be welded?
Not readily — weldability is rated not recommended (5/100). Weldable only before carburizing — preheat 200–250 °C, low-hydrogen consumables, post-weld stress relief; never weld a case-hardened surface.
What surface finishes work on 20MnCr5-CH?
No anodizing; protect with oil, black oxide, Mn-phosphate or zinc plating (bake for hydrogen relief), and shot-peen gear roots to boost bending fatigue.
Can 20MnCr5-CH be formed, bent or molded?
Good hot forgeability at 1100–1200 °C and good cold-heading behaviour after spheroidize annealing; normalize after forging before machining.
What is the maximum service temperature of 20MnCr5-CH?
20MnCr5-CH is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20MnCr5-HR and 20MnCr5-CH?
HR is the default condition — standard stock condition for gear blanks that will be machined then carburized. CH: the service condition for gears: 58–62 HRC case over a tough 30–40 HRC core, high contact and bending fatigue strength. Yield strength is 460 MPa in HR versus 780 MPa in CH.
Can FabDigit make parts in 20MnCr5-CH?
Yes — 20MnCr5-CH 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
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10277 — Bright steel products — CEN (2018)
- GB/T 3077 (20CrMn/20CrMnH ) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing of Mn-Cr steels) — ASM International (1991)
- Case hardening steel 20MnCr5 (1.7147) bar datasheet — Ovako / Böhler-Uddeholm (2021)
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.