Steel 40Cr · supply condition · default condition
Steel 40Cr-HR
Properties of the HR condition, compared with the other 40Cr tempers.
Standard stocked as-rolled bar; buy this and heat treat after rough machining.
What is 40Cr-HR?
40Cr-HR is 40Cr supplied in the HR condition — standard stocked as-rolled bar; buy this and heat treat after rough machining. 40Cr-HR has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 51% of steel grades. Elongation at break is 16% and the elastic modulus is 211 GPa (30.6 Msi). 40Cr-HR 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).
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 83% of steel grades
40Cr-HR properties
Typical room-temperature values for 40Cr-HR — 10 properties are specific to this condition; the rest are grade-level values shared by every 40Cr temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
40Cr-HR 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
40Cr-HR has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 51% of steel grades. Elongation at break is 16% and the elastic modulus is 211 GPa (30.6 Msi).
Thermal6
40Cr-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
40Cr-HR conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 40Cr-HR takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 35%.
Manufacturability7
40Cr-HR's machinability is good (55/100, better than 62% of steel grades); weldability fair (45/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 40Cr tempers and conditions
40Cr is also supplied in 9 other conditions. The full side-by-side table is on the 40Cr overview.
- HRDefaultStandard stocked as-rolled bar; buy this and heat treat after rough machining.430 MPa yield · 210 HB
- Q&T 35-40 HRCHigher-strength temper for gears, couplings and wear-loaded parts; toughness and machinability drop.1,050 MPa yield · 38 HRC
- Q&TStandard GB/T 3077 delivery-condition property set; the usual choice for shafts, gears and high-strength bolts.830 MPa yield · 31 HRC
- Q&T 28-32 HRCToughness-first condition for large shafts and parts still to be machined after heat treatment.790 MPa yield · 30 HRC
- CDCold-drawn bright bar: tighter tolerance, better surface and free-er chip than hot rolled.650 MPa yield · 229 HB
- NormalizedAir-cooled from ~860 °C for uniform fine pearlitic structure and predictable machining before Q&T.500 MPa yield · 229 HB
- AnnealedSoftest condition (≤207 HB per GB/T 3077) for deep machining, cold forming or before final hardening.400 MPa yield · 187 HB
Working with 40Cr-HR
Is 40Cr easy to machine?
Best machined annealed or normalized at 180–230 HB with carbide tooling (~120–180 m/min); above 35 HRC switch to coated carbide/CBN and reduce feed.
Can 40Cr be welded?
Weldable with care only — preheat 200–300 °C, low-hydrogen consumables, and temper immediately after welding; avoid welding fully hardened parts.
Can 40Cr be formed, bent or molded?
Hot forge 1150–850 °C then normalize; cold bending only in the annealed condition with generous radii (≥3t).
What surface finishes work on 40Cr?
No native corrosion protection: use black oxide, manganese phosphate, zinc or hard chrome plating (bake to de-embrittle above ~1000 MPa); polishes well after Q&T.
40Cr 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 | 0.37 – 0.44 | 0.4 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.8 – 1.1 | 0.95 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| Moresidual, not intentionally added | ≤ 0.1 | — |
| P0.025 max for high-grade quality | ≤ 0.04 | — |
| S0.025 max for high-grade quality | ≤ 0.04 | — |
| Fe | balance | — |
40Cr-HR — frequently asked
What is 40Cr-HR used for?
40Cr-HR is typically used for drive shafts, industrial bolts and crankshafts. In short: chrome alloy machining bar.
What is the yield strength of 40Cr-HR?
40Cr-HR has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 51% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 40Cr-HR easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Best machined annealed or normalized at 180–230 HB with carbide tooling (~120–180 m/min); above 35 HRC switch to coated carbide/CBN and reduce feed.
Can 40Cr-HR be welded?
With care — weldability is rated fair (45/100). Weldable with care only — preheat 200–300 °C, low-hydrogen consumables, and temper immediately after welding; avoid welding fully hardened parts.
What surface finishes work on 40Cr-HR?
No native corrosion protection: use black oxide, manganese phosphate, zinc or hard chrome plating (bake to de-embrittle above ~1000 MPa); polishes well after Q&T.
Can 40Cr-HR be formed, bent or molded?
Hot forge 1150–850 °C then normalize; cold bending only in the annealed condition with generous radii (≥3t).
What is the maximum service temperature of 40Cr-HR?
40Cr-HR is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 40Cr-HR and 40Cr-IH?
HR is the default condition — standard stocked as-rolled bar; buy this and heat treat after rough machining. IH: choose when only the running surface (journal, spline, gear tooth) needs 50+ HRC wear resistance over a tough core. Yield strength is 430 MPa in HR versus 830 MPa in IH.
Can FabDigit make parts in 40Cr-HR?
Yes — 40Cr-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
- GB/T 3077 Alloy structural steels (2015)
- SAE J404 Chemical Compositions of SAE Alloy Steels (5140) — SAE International (2018)
- EN 10083-3 (41Cr4 / 1.7035) — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
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.