Steel 40CrV QT40-45HRC
Hardness band
GB 40CrV
QT40-45HRC = q&T to 40–45 HRC
High fatigue-strength condition for torsion bars, heavy springs and highly loaded pins.
Values for the QT40-45HRC condition
Other 40CrV tempers and conditions
40CrV is listed in 11 conditions; see the grade overview at 40CrV.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest supply condition for deep machining, cold cutting and forging stock before final heat treatment. | 400 | 670 | 22 | 197 HB | — |
Hot rolled | Mill supply condition for bar and billet that will be heat treated by the part maker. | 460 | 760 | 16 | 19 HRC | 8.1 % IACS |
Normalized | Uniform fine-grained structure for forgings and as a pre-treatment before quenching; medium strength without full Q&T cost. | 520 | 800 | 17 | 21 HRC | 8.1 % IACS |
Cold drawn | Bright bar with close tolerance and higher yield for shafts and fasteners machined without further heat treatment. | 700 | 850 | 10 | 25 HRC | 7.9 % IACS |
QTDefault Quenched and tempered | Standard commercial quenched and tempered stock — 880 °C oil quench plus 650 °C temper — for shafts and gears needing 810 MPa yield with 13 % elongation and good impact toughness. | 810 | 980 | 13 | 30 HRC | — |
Induction hardened | Wear-resistant surface with tough core for journals, gear teeth and spline shafts. | 810 | 980 | 12 | 56 HRC | 7.5 % IACS |
Q&T to 28–32 HRC | Tough general machine-part hardness; still readily machinable after heat treatment. | 850 | 1,000 | 14 | 30 HRC | 7.8 % IACS |
Q&T to 33–38 HRC | Higher-strength shafts, torsion bars and moderately loaded gears where toughness is still needed. | 1,010 | 1,150 | 12 | 35 HRC | — |
QT40-45HRCThis page Q&T to 40–45 HRC | High fatigue-strength condition for torsion bars, heavy springs and highly loaded pins. | 1,250 | 1,380 | 9 | 43 HRC | — |
Q&T to 48–52 HRC | Spring/leaf and high-elastic-limit parts; low ductility and notch sensitivity must be designed around. | 1,500 | 1,700 | 7 | 50 HRC | — |
As-quenched (oil, 860–880 °C), untempered | Intermediate state only — must be tempered promptly; quoted for hardenability reference. | 1,550 | 1,980 | 2 | 56 HRC | 5.6 % IACS |
What is 40CrV QT40-45HRC?
40CrV QT40-45HRC is 40CrV heat treated to QT40-45HRC — high fatigue-strength condition for torsion bars, heavy springs and highly loaded pins. 40CrV QT40-45HRC has a yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,380 MPa (200 ksi) — stronger than 95% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi). 40CrV QT40-45HRC 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). QT is the default condition FabDigit quotes; QT40-45HRC is available on request or by drawing note.
Advantages
- High strength — 1,250 MPa (181 ksi), better than 95% of steel grades
Limitations
- Limited ductility — 9%, worse than 93% of steel grades
- Difficult to machine — 28/100, worse than 91% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
40CrV QT40-45HRC properties
Typical room-temperature values for 40CrV QT40-45HRC; 10 are specific to this condition. Other listed values are 40CrV reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
40CrV QT40-45HRC 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
40CrV QT40-45HRC has a yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,380 MPa (200 ksi) — stronger than 95% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
40CrV QT40-45HRC is rated for continuous service to 300°C (572 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
40CrV QT40-45HRC conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 40CrV QT40-45HRC takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability6
40CrV QT40-45HRC's machinability is poor (28/100, worse than 91% of steel grades); weldability fair (35/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 40CrV QT40-45HRC
Is 40CrV easy to machine?
Machine in the annealed or ≤32 HRC Q&T state with carbide tooling and rigid setups; above 40 HRC switch to CBN/ceramic or grinding.
Can 40CrV be welded?
Weldable only with care — preheat 250–350 °C, low-hydrogen consumables, and temper/stress relieve at 550–650 °C after welding; avoid welding fully hardened parts.
Can 40CrV be formed, bent or molded?
Hot forge at 1150–850 °C then normalize; cold bending is limited and should be done annealed with generous radii.
What surface finishes work on 40CrV?
No natural corrosion protection — use black oxide, phosphate + oil, zinc or hard-chrome plating; grind and shot peen for fatigue-critical surfaces.
40CrV 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 |
|---|---|---|
| CGB/T 3077 | 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 |
| Vgrain refinement, temper resistance | 0.1 – 0.2 | 0.15 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Niresidual max | ≤ 0.3 | — |
| Curesidual max | ≤ 0.25 | — |
| Fe | balance | — |
40CrV QT40-45HRC — frequently asked
What is 40CrV QT40-45HRC used for?
40CrV QT40-45HRC is typically used for shafts, springs, gears and tool holders. In short: cr-V fatigue-resistant steel; good temper resistance; wide Q&T hardness range.
What is the yield strength of 40CrV QT40-45HRC?
40CrV QT40-45HRC has a typical yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,380 MPa (200 ksi) — stronger than 95% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 40CrV QT40-45HRC easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Machine in the annealed or ≤32 HRC Q&T state with carbide tooling and rigid setups; above 40 HRC switch to CBN/ceramic or grinding.
Can 40CrV QT40-45HRC be welded?
With care — weldability is rated fair (35/100). Weldable only with care — preheat 250–350 °C, low-hydrogen consumables, and temper/stress relieve at 550–650 °C after welding; avoid welding fully hardened parts.
What surface finishes work on 40CrV QT40-45HRC?
No natural corrosion protection — use black oxide, phosphate + oil, zinc or hard-chrome plating; grind and shot peen for fatigue-critical surfaces.
Can 40CrV QT40-45HRC be formed, bent or molded?
Hot forge at 1150–850 °C then normalize; cold bending is limited and should be done annealed with generous radii.
What is the maximum service temperature of 40CrV QT40-45HRC?
40CrV QT40-45HRC is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 40CrV-QT and 40CrV-Q?
QT is the default condition — standard commercial quenched and tempered stock — 880 °C oil quench plus 650 °C temper — for shafts and gears needing 810 MPa yield with 13 % elongation and good impact toughness. Q: intermediate state only — must be tempered promptly; quoted for hardenability reference. Yield strength is 810 MPa in QT versus 1,550 MPa in Q.
Sources
- GB/T 699 / GB/T 1172 hardness–strength conversion — SAC (1999)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Machinery's Handbook, 31st ed. — Industrial Press (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.