Steel 40Cr Annealed
Temper
GB 40Cr
Softest condition (≤207 HB per GB/T 3077) for deep machining, cold forming or before final hardening.
Values for the Annealed condition
Other 40Cr tempers and conditions
40Cr is listed in 10 conditions; see the grade overview at 40Cr.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page Temper | Softest condition (≤207 HB per GB/T 3077) for deep machining, cold forming or before final hardening. | 400 | 680 | 22 | 187 HB | — |
HRDefault Hot rolled | Standard stocked as-rolled bar; buy this and heat treat after rough machining. | 430 | 720 | 16 | 210 HB | — |
Heat Treat State | Air-cooled from ~860 °C for uniform fine pearlitic structure and predictable machining before Q&T. | 500 | 800 | 18 | 20 HRC | 8 % IACS |
Cold rolled | Cold-rolled strip/sheet for stamped and formed parts that will be hardened later. | 620 | 800 | 10 | 22 HRC | 8 % IACS |
Cold drawn | Cold-drawn bright bar: tighter tolerance, better surface and free-er chip than hot rolled. | 650 | 790 | 12 | 229 HB | — |
Q&T to 28–32 HRC | Toughness-first condition for large shafts and parts still to be machined after heat treatment. | 790 | 950 | 14 | 30 HRC | — |
Quenched and tempered | Standard GB/T 3077 delivery-condition property set; the usual choice for shafts, gears and high-strength bolts. | 830 | 1,020 | 12 | 31 HRC | — |
Induction hardened | Choose when only the running surface (journal, spline, gear tooth) needs 50+ HRC wear resistance over a tough core. | 830 | 1,020 | 12 | 55 HRC | 7 % IACS |
Gas/ion nitrided (after Q&T) | Use for low-distortion wear and scuffing resistance on already-finished Q&T parts; case is thin (0.2–0.4 mm). | 830 | 1,020 | 11 | 57 HRC | 8 % IACS |
Q&T to 35–40 HRC | Higher-strength temper for gears, couplings and wear-loaded parts; toughness and machinability drop. | 1,050 | 1,200 | 10 | 38 HRC | — |
What is 40Cr Annealed?
40Cr Annealed is 40Cr in the Annealed temper — softest condition (≤207 HB per GB/T 3077) for deep machining, cold forming or before final hardening. 40Cr Annealed has a yield strength of 400 MPa (58 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of steel grades. Elongation at break is 22% and the elastic modulus is 211 GPa (30.6 Msi). 40Cr Annealed 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; Annealed is available on request or by drawing note.
Advantages
- Easy to machine — 65/100, better than 93% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
40Cr Annealed properties
Typical room-temperature values for 40Cr Annealed; 11 are specific to this condition. Other listed values are 40Cr reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
40Cr Annealed 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 Annealed has a yield strength of 400 MPa (58 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of steel grades. Elongation at break is 22% and the elastic modulus is 211 GPa (30.6 Msi).
Thermal6
40Cr Annealed 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 Annealed 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 Annealed 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 Annealed's machinability is good (65/100, better than 93% of steel grades); weldability fair (50/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 40Cr Annealed
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 Annealed — frequently asked
What is 40Cr Annealed used for?
40Cr Annealed is typically used for drive shafts, industrial bolts and crankshafts. In short: chrome alloy machining bar.
What is the yield strength of 40Cr Annealed?
40Cr Annealed has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 40Cr Annealed easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% 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 Annealed be welded?
With care — weldability is rated fair (50/100). 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 Annealed?
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 Annealed 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 Annealed?
40Cr Annealed 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 Annealed?
Yes — 40Cr Annealed 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.