Steel 17CrNi6-6-CH (Carburized and hardened)
Heat-treated state
EN 17CrNi6-6
Final in-service condition for gears and shafts: hard, wear- and pitting-resistant case over a tough Cr-Ni core.
Values for the CH condition
Other 17CrNi6-6 tempers and conditions
17CrNi6-6 is listed in 7 conditions; see the grade overview at 17CrNi6-6.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold forming, cold heading or deep drilling where the lowest hardness and best ductility are needed. | 330 | 560 | 22 | 165 HB | — |
Treated for shearability | Pick for coil/bar that must be cold-sheared or cropped into blanks before machining and carburizing. | 360 | 600 | 19 | 175 HB | 7 % IACS |
+FPDefault Annealed to a ferrite–pearlite structure and hardness range | Standard gear-blank delivery condition: uniform ferrite–pearlite gives predictable machining and low distortion in carburizing. | 375 | 620 | 18 | 180 HB | — |
Normalized | Use to refine grain and homogenize forgings before soft annealing or machining. | 420 | 680 | 17 | 14 HRC | 7 % IACS |
Spheroidize annealed and cold drawn | Precision bright bar for automatic-lathe parts and pins: tight tolerance, higher yield, straighter chips. | 560 | 700 | 10 | 210 HB | — |
Hardenability-guaranteed (Jominy) quality, supplied hardened/tempered… | Specify when Jominy end-quench hardenability must be guaranteed and the part is hardened and tempered to a defined core strength. | 850 | 1,100 | 11 | 34 HRC | — |
CHThis page Carburized and hardened | Final in-service condition for gears and shafts: hard, wear- and pitting-resistant case over a tough Cr-Ni core. | 900 | 1,200 | 9 | 60 HRC | — |
What is 17CrNi6-6-CH?
17CrNi6-6-CH is 17CrNi6-6 heat treated to CH — final in-service condition for gears and shafts: hard, wear- and pitting-resistant case over a tough Cr-Ni core. 17CrNi6-6-CH has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 90% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi). 17CrNi6-6-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). +FP 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 — 900 MPa (131 ksi), better than 90% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 5/100, 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
17CrNi6-6-CH properties
Typical room-temperature values for 17CrNi6-6-CH; 14 are specific to this condition. Other listed values are 17CrNi6-6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
17CrNi6-6-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).
Mechanical16
17CrNi6-6-CH has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 90% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
17CrNi6-6-CH is rated for continuous service to 180°C (356 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
17CrNi6-6-CH conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of 17CrNi6-6-CH takes about 31 MJ of energy and emits 2.2 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability8
17CrNi6-6-CH's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (10/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 17CrNi6-6-CH
Is 17CrNi6-6 easy to machine?
Machine in +FP or +AC before carburizing; coated carbide, moderate speeds and rigid setups — nickel content makes it gummy in the fully soft state, so finish-grind after hardening.
Can 17CrNi6-6 be welded?
Weldable only with care: preheat 200–300 °C, low-hydrogen consumables and immediate stress relief; never weld carburized surfaces.
Can 17CrNi6-6 be formed, bent or molded?
Hot forge 1100–850 °C followed by normalizing; cold heading and drawing are practical only in the spheroidized (+AC) condition.
What surface finishes work on 17CrNi6-6?
Case-hardened parts are hard-turned or ground and honed; protect with oil, manganese phosphate, black oxide or zinc plating (bake to avoid hydrogen embrittlement).
17CrNi6-6 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 | 0.14 – 0.2 | 0.17 |
| Simax per EN 10084 | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | 0.01 |
| Smax; +S variant 0.020–0.040 for machinability | ≤ 0.04 | 0.02 |
| Cr | 1.4 – 1.7 | 1.55 |
| Ni | 1.4 – 1.7 | 1.55 |
| Moresidual, not specified | ≤ 0.1 | 0.03 |
| Fe | balance | — |
17CrNi6-6-CH — frequently asked
What is 17CrNi6-6-CH used for?
17CrNi6-6-CH is typically used for transmission gears, gearbox shafts and aerospace gears. In short: aerospace gear steel; tough carburized core; AISI 9310 equivalent.
What is the yield strength of 17CrNi6-6-CH?
17CrNi6-6-CH has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 17CrNi6-6-CH easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in +FP or +AC before carburizing; coated carbide, moderate speeds and rigid setups — nickel content makes it gummy in the fully soft state, so finish-grind after hardening.
Can 17CrNi6-6-CH be welded?
Not readily — weldability is rated not recommended (10/100). Weldable only with care: preheat 200–300 °C, low-hydrogen consumables and immediate stress relief; never weld carburized surfaces.
What surface finishes work on 17CrNi6-6-CH?
Case-hardened parts are hard-turned or ground and honed; protect with oil, manganese phosphate, black oxide or zinc plating (bake to avoid hydrogen embrittlement).
Can 17CrNi6-6-CH be formed, bent or molded?
Hot forge 1100–850 °C followed by normalizing; cold heading and drawing are practical only in the spheroidized (+AC) condition.
What is the maximum service temperature of 17CrNi6-6-CH?
17CrNi6-6-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 17CrNi6-6 +FP and 17CrNi6-6-CH?
+FP is the default condition — standard gear-blank delivery condition: uniform ferrite–pearlite gives predictable machining and low distortion in carburizing. CH: final in-service condition for gears and shafts: hard, wear- and pitting-resistant case over a tough Cr-Ni core. Yield strength is 375 MPa in +FP versus 900 MPa in CH.
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 — ASM International (2013)
- Case hardening steel 1.5918 / 17CrNi6-6 data sheet — Ovako / Deutsche Edelstahlwerke (2020)
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.