Steel 17CrNiMo6-4-CH (Carburized and hardened)
Heat-treated state
EN 17CrNiMo6-4
Specify carburized, quenched and low-temperature tempered parts as the final gear and shaft state: a 58–62 HRC case resists pitting and wear over a tough core, with no machining left.
Values for the CH condition
Other 17CrNiMo6-4 tempers and conditions
17CrNiMo6-4 is listed in 8 conditions; see the grade overview at 17CrNiMo6-4.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Treated for cold shearing | Use for cold shearing of wire and bar cut-offs, where the capped hardness of about 175 HB and 620 MPa tensile prevents shear cracking at the cost of strength. | 380 | 620 | 19 | 175 HB | 7.8 % IACS |
Treated to ferrite-pearlite structure and hardness range | Pick the controlled ferrite-pearlite structure and hardness band (about 170 HB) when automatic machining lines need predictable chip formation and stable tool life before carburizing. | 390 | 620 | 19 | 170 HB | 7.8 % IACS |
Treated to specified hardness range | Order to a contractually agreed hardness range (about 180 HB, 640 MPa tensile) when high-volume machining ahead of case hardening requires batch-to-batch consistency. | 395 | 640 | 18 | 180 HB | 7.8 % IACS |
+ADefault Annealed | Choose the soft-annealed (spheroidized, ≤229 HB) bar or forging blank for rough turning, gear hobbing and cold forming, before the parts are carburized and quenched. | 400 | 650 | 18 | 185 HB | 7.8 % IACS |
Normalized | Pick normalized forgings to refine grain and homogenize the structure as a preparatory treatment before carburizing; the 225 HB level reduces machinability. | 500 | 780 | 15 | 19 HRC | 7.7 % IACS |
Cold drawn | Choose annealed-then-cold-drawn bright bar in small diameters for tight size tolerance and minimal finish-turning allowance; drawing lifts strength but cuts elongation to 10%. | 580 | 760 | 10 | 18 HRC | 7.8 % IACS |
Blank-hardened (quenched & tempered without carburizing), core… | Use blank hardening — quenched and tempered without carburizing — to qualify core strength or for high-strength shafts at 1150 MPa and 350 HB, accepting poor machining and welding. | 830 | 1,150 | 10 | 37 HRC | — |
CHThis page Carburized and hardened | Specify carburized, quenched and low-temperature tempered parts as the final gear and shaft state: a 58–62 HRC case resists pitting and wear over a tough core, with no machining left. | 830 | 1,150 | 9 | 60 HRC | — |
What is 17CrNiMo6-4-CH?
17CrNiMo6-4-CH is 17CrNiMo6-4 heat treated to CH — specify carburized, quenched and low-temperature tempered parts as the final gear and shaft state: a 58–62 HRC case resists pitting and wear over a tough core, with no machining left. 17CrNiMo6-4-CH has a yield strength of 830 MPa (120 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 87% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi). 17CrNiMo6-4-CH has a density of 7.84 g/cm³ (0.283 lb/in³), lighter than 78% of steel grades. It melts at 1,420°C (2,588 °F). +A 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 — 830 MPa (120 ksi), better than 87% of steel grades
Limitations
- Difficult to machine — 10/100, 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
- Limited ductility — 9%, worse than 93% of steel grades
17CrNiMo6-4-CH properties
Typical room-temperature values for 17CrNiMo6-4-CH; 13 are specific to this condition. Other listed values are 17CrNiMo6-4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
17CrNiMo6-4-CH has a density of 7.84 g/cm³ (0.283 lb/in³), lighter than 78% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
17CrNiMo6-4-CH has a yield strength of 830 MPa (120 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 87% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
17CrNiMo6-4-CH is rated for continuous service to 180°C (356 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
17CrNiMo6-4-CH conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 17CrNiMo6-4-CH 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
17CrNiMo6-4-CH's machinability is not recommended (10/100, worse than 99% of steel grades); weldability not recommended (10/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 17CrNiMo6-4-CH
Is 17CrNiMo6-4 easy to machine?
Turning, milling and hobbing run well in the annealed (+A) or ferrite-pearlite (+FP) condition. After carburizing and quenching, only grinding or CBN hard turning is practical.
Can 17CrNiMo6-4 be welded?
The low carbon content allows welding, but the Ni-Cr-Mo composition hardens readily: preheat 150–250 °C, use low-hydrogen consumables and stress relieve after welding. Do not weld in carburized areas.
Can 17CrNiMo6-4 be formed, bent or molded?
Hot forge 1050–1150 °C; in the soft-annealed condition the steel also takes cold heading and cold extrusion. Normalize or anneal after forming and before carburizing.
What surface finishes work on 17CrNiMo6-4?
After carburizing and grinding, parts can be black oxided, phosphated, zinc plated or shot peened — shot peening significantly increases tooth-root bending fatigue life. There is no inherent corrosion resistance, so rust protection is required.
17CrNiMo6-4 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 |
|---|---|---|
| CEN 10084 (17NiCrMo6-4 / 1.6566) | 0.14 – 0.2 | 0.17 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| Pimpurity maximum | ≤ 0.03 | — |
| Sin +S condition may be 0.020–0.040 | ≤ 0.04 | — |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| Ni | 1.2 – 1.5 | 1.35 |
| Fe | balance | — |
17CrNiMo6-4-CH — frequently asked
What is 17CrNiMo6-4-CH used for?
17CrNiMo6-4-CH is typically used for automotive transmission gears, industrial gearbox gears and pinions, wind turbine gearbox components, splined shafts, ring and bevel gears and heavy-duty gear blanks. In short: mid-range Ni-Cr-Mo case steel; good core toughness; between 16MnCr5 and 18CrNiMo7-6.
What is the yield strength of 17CrNiMo6-4-CH?
17CrNiMo6-4-CH has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 87% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 17CrNiMo6-4-CH easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Turning, milling and hobbing run well in the annealed (+A) or ferrite-pearlite (+FP) condition. After carburizing and quenching, only grinding or CBN hard turning is practical.
Can 17CrNiMo6-4-CH be welded?
Not readily — weldability is rated not recommended (10/100). The low carbon content allows welding, but the Ni-Cr-Mo composition hardens readily: preheat 150–250 °C, use low-hydrogen consumables and stress relieve after welding. Do not weld in carburized areas.
What surface finishes work on 17CrNiMo6-4-CH?
After carburizing and grinding, parts can be black oxided, phosphated, zinc plated or shot peened — shot peening significantly increases tooth-root bending fatigue life. There is no inherent corrosion resistance, so rust protection is required.
Can 17CrNiMo6-4-CH be formed, bent or molded?
Hot forge 1050–1150 °C; in the soft-annealed condition the steel also takes cold heading and cold extrusion. Normalize or anneal after forming and before carburizing.
What is the maximum service temperature of 17CrNiMo6-4-CH?
17CrNiMo6-4-CH 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 17CrNiMo6-4 +A and 17CrNiMo6-4-BH?
+A is the default condition — choose the soft-annealed (spheroidized, ≤229 HB) bar or forging blank for rough turning, gear hobbing and cold forming, before the parts are carburized and quenched. BH: use blank hardening — quenched and tempered without carburizing — to qualify core strength or for high-strength shafts at 1150 MPa and 350 HB, accepting poor machining and welding. Yield strength is 400 MPa in +A versus 830 MPa in BH.
Sources
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
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.