Steel 18CrNi8 · supply condition · default condition
Steel 18CrNi8-HR
Properties of the HR condition, compared with the other 18CrNi8 tempers.
Standard mill delivery for forging, rough machining and subsequent carburizing; hardness is uncontrolled and can be high because of the Cr-Ni content.
What is 18CrNi8-HR?
18CrNi8-HR is 18CrNi8 supplied in the HR condition — standard mill delivery for forging, rough machining and subsequent carburizing; hardness is uncontrolled and can be high because of the Cr-Ni content. 18CrNi8-HR has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 74% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi). 18CrNi8-HR 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).
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
- Difficult to machine — 40/100, worse than 76% of steel grades
18CrNi8-HR properties
Typical room-temperature values for 18CrNi8-HR — 9 properties are specific to this condition; the rest are grade-level values shared by every 18CrNi8 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
18CrNi8-HR 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).
Mechanical14
18CrNi8-HR has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 74% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
18CrNi8-HR is rated for continuous service to 200°C (392 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical2
18CrNi8-HR has an electrical resistivity of 2.5×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 18CrNi8-HR takes about 33 MJ of energy and emits 2.3 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 30%.
Manufacturability6
18CrNi8-HR's machinability is fair (40/100, worse than 76% of steel grades); weldability fair (35/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 18CrNi8 tempers and conditions
18CrNi8 is also supplied in 9 other conditions. The full side-by-side table is on the 18CrNi8 overview.
- HRDefaultStandard mill delivery for forging, rough machining and subsequent carburizing; hardness is uncontrolled and can be high because of the Cr-Ni content.570 MPa yield · 255 HB
- BGReference condition of EN 10084 used to verify core properties; also used for small parts needing through-hardened high strength.900 MPa yield · 41 HRC
- CHThe functional condition for gears and shafts: hard wear-resistant case with compressive residual stress over a tough 1100–1300 MPa core.880 MPa yield · 60 HRC
- Q&TNon-carburized through-hardened option for shafts and fasteners where toughness matters more than surface wear.830 MPa yield · 31 HRC
- NormalizedUsed to homogenize forgings before final annealing; with 2 % Cr + 2 % Ni air cooling already produces a hard bainitic/martensitic structure.670 MPa yield · 29 HRC
- AnnealedPick for maximum machinability and cold-working ability before carburizing; softest standard delivery condition.440 MPa yield · 205 HB
Working with 18CrNi8-HR
Is 18CrNi8 easy to machine?
Machine in the soft-annealed or +FP condition (≤229 HB) with carbide tooling, moderate speeds and generous coolant; leave 0.2–0.5 mm stock for post-carburizing grinding since 58–62 HRC surfaces need CBN/grinding only.
Can 18CrNi8 be welded?
Weld only in the annealed state with 200–300 °C preheat, low-hydrogen or matching-Ni consumables, then re-normalize/anneal; carburized surfaces must not be welded (cracking, case decarburization).
Can 18CrNi8 be formed, bent or molded?
Hot forge 1100–850 °C with slow cooling and mandatory post-forge normalize + soft anneal; cold heading/upsetting only in the annealed or spheroidized condition.
What surface finishes work on 18CrNi8?
No anodizing (steel); protect with oil, phosphate, black oxide, zinc-nickel or hard chrome; ground and superfinished gear flanks improve fatigue and pitting life, shot peening adds compressive stress.
18CrNi8 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 | 0.15 – 0.2 | 0.18 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.6 | 0.5 |
| Pmax (EN 10084) | ≤ 0.03 | — |
| Smax; low-S or controlled-S variants available | ≤ 0.04 | — |
| Cr | 1.8 – 2.1 | 1.95 |
| Ni | 1.8 – 2.1 | 1.95 |
| Moresidual, not intentionally added | ≤ 0.1 | — |
| Fe | balance | — |
18CrNi8-HR — frequently asked
What is 18CrNi8-HR used for?
18CrNi8-HR is typically used for gears, industrial drive shafts and pins. In short: high-strength Ni-Cr bar.
What is the yield strength of 18CrNi8-HR?
18CrNi8-HR has a typical yield strength of 570 MPa (82.7 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 74% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 18CrNi8-HR easy to machine?
Not especially — machinability is rated fair (40/100, worse than 76% of steel grades). Machine in the soft-annealed or +FP condition (≤229 HB) with carbide tooling, moderate speeds and generous coolant; leave 0.2–0.5 mm stock for post-carburizing grinding since 58–62 HRC surfaces need CBN/grinding only.
Can 18CrNi8-HR be welded?
With care — weldability is rated fair (35/100). Weld only in the annealed state with 200–300 °C preheat, low-hydrogen or matching-Ni consumables, then re-normalize/anneal; carburized surfaces must not be welded (cracking, case decarburization).
What surface finishes work on 18CrNi8-HR?
No anodizing (steel); protect with oil, phosphate, black oxide, zinc-nickel or hard chrome; ground and superfinished gear flanks improve fatigue and pitting life, shot peening adds compressive stress.
Can 18CrNi8-HR be formed, bent or molded?
Hot forge 1100–850 °C with slow cooling and mandatory post-forge normalize + soft anneal; cold heading/upsetting only in the annealed or spheroidized condition.
What is the maximum service temperature of 18CrNi8-HR?
18CrNi8-HR 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.
What is the difference between 18CrNi8-HR and 18CrNi8-BG?
HR is the default condition — standard mill delivery for forging, rough machining and subsequent carburizing; hardness is uncontrolled and can be high because of the Cr-Ni content. BG: reference condition of EN 10084 used to verify core properties; also used for small parts needing through-hardened high strength. Yield strength is 570 MPa in HR versus 900 MPa in BG.
Can FabDigit make parts in 18CrNi8-HR?
Yes — 18CrNi8-HR 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)
- DIN 17210 (withdrawn) / SEW 550 case hardening steel data — DIN / VDEh (1987)
- 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 18CrNi8 / 1.5920 bar datasheet — Ovako / Böhler / Lucchini-type mill data (2022)
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.