Steel 50CrMo4 +QT (Quenched and tempered)
Heat-treated state · default condition
EN 50CrMo4
Standard stocked condition: oil/polymer quench from ~840 °C, temper 540–680 °C for balanced strength and toughness.
Values for the +QT condition
Other 50CrMo4 tempers and conditions
50CrMo4 is listed in 13 conditions; see the grade overview at 50CrMo4.
Compare all 13 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for machining, deep drilling or cold sawing before final hardening. | 440 | 760 | 18 | 230 HB | — |
Hot rolled | Cheapest stock form, bought for forging or full re-heat-treatment by the user. | 500 | 850 | 14 | 25 HRC | 8.2 % IACS |
Normalized | Uniform pearlitic structure for forging stock or before final quench-and-temper. | 550 | 900 | 15 | 27 HRC | — |
+QT | Large-diameter forged shafts and rolls where only partial hardening depth is possible. | 570 | 870 | 14 | 26 HRC | 7.8 % IACS |
+QT | Medium shafts and forgings; strength reduced by mass effect. | 700 | 1,000 | 12 | 31 HRC | 7.8 % IACS |
Cold drawn | Close-tolerance bright bar for parts finished without further heat treatment. | 700 | 880 | 10 | 26 HRC | 8.2 % IACS |
Q&T to 28–32 HRC | Pick when impact toughness and machinability matter more than wear. | 830 | 980 | 15 | 30 HRC | — |
+QTDefaultThis page Quenched and tempered | Standard stocked condition: oil/polymer quench from ~840 °C, temper 540–680 °C for balanced strength and toughness. | 850 | 1,100 | 11 | 34 HRC | — |
Induction hardened | Best choice for journals, spline flanks and hydraulic rods needing surface wear plus tough core. | 850 | 1,100 | 10 | 58 HRC | 7.5 % IACS |
+QT | Thin bars/pins where full martensitic hardening through-section is achieved. | 950 | 1,200 | 10 | 38 HRC | 7.8 % IACS |
Q&T to 34–38 HRC | Common pre-hardened supply for shafts, spindles and holder bodies machined to finish size. | 1,000 | 1,150 | 12 | 36 HRC | — |
Q&T to 40–45 HRC | For collets, chucks, wear plates and tool bodies needing hardness with some toughness. | 1,220 | 1,380 | 10 | 43 HRC | — |
Hardened + low temper (180–250 °C), 50–55 HRC | Maximum hardness/wear condition for dies, guides and cams; low toughness, grind-finish only. | 1,500 | 1,800 | 5 | 53 HRC | — |
What is 50CrMo4 +QT?
50CrMo4 +QT is 50CrMo4 heat treated to +QT — standard stocked condition: oil/polymer quench from ~840 °C, temper 540–680 °C for balanced strength and toughness. 50CrMo4 +QT has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 88% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). 50CrMo4 +QT 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
- High strength — 850 MPa (123 ksi), better than 88% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to weld — 22/100, worse than 81% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
50CrMo4 +QT properties
Typical room-temperature values for 50CrMo4 +QT; 14 are specific to this condition. Other listed values are 50CrMo4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
50CrMo4 +QT 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).
Mechanical16
50CrMo4 +QT has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 88% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
50CrMo4 +QT is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.2 µm/m·K (6.22 µin/in·°F).
Electrical3
50CrMo4 +QT conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 50CrMo4 +QT takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability8
50CrMo4 +QT's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (22/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 50CrMo4 +QT
Is 50CrMo4 easy to machine?
Machine in +A or ≤32 HRC condition with coated carbide (Vc ≈ 120–180 m/min annealed, 60–100 m/min at 34 HRC); above 45 HRC switch to CBN hard turning or grinding.
Can 50CrMo4 be welded?
Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, interpass control and immediate 600–660 °C PWHT; avoid welding in the hardened condition.
Can 50CrMo4 be formed, bent or molded?
Hot form/forge 1100→850 °C with slow cooling in furnace or ash; cold bending or heading is not practical — use annealed stock and small strains only.
What surface finishes work on 50CrMo4?
Not anodizable; protect with black oxide, manganese phosphate, zinc or hard chrome plating, or gas nitride (Q&T ≥ tempering above 550 °C) — bake at 190–220 °C after plating to avoid hydrogen embrittlement.
50CrMo4 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 |
|---|---|---|
| CEN 10083-3 | 0.46 – 0.54 | 0.5 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.03 | 0.02 |
| S≤0.035 standard; ≤0.005 for quality class +S grades | ≤ 0.04 | 0.02 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Fe | balance | — |
50CrMo4 +QT — frequently asked
What is 50CrMo4 +QT used for?
50CrMo4 +QT is typically used for high-strength bolts, springs, gears, molds and structural shafts. In short: higher-carbon 42CrMo4 upgrade; through-hardens above 40 HRC; poor weldability by design.
What is the yield strength of 50CrMo4 +QT?
50CrMo4 +QT has a typical yield strength of 850 MPa (123 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 88% of steel grades. Strength varies by condition: see the 13 listed tempers.
Is 50CrMo4 +QT easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in +A or ≤32 HRC condition with coated carbide (Vc ≈ 120–180 m/min annealed, 60–100 m/min at 34 HRC); above 45 HRC switch to CBN hard turning or grinding.
Can 50CrMo4 +QT be welded?
Not readily — weldability is rated poor (22/100). Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, interpass control and immediate 600–660 °C PWHT; avoid welding in the hardened condition.
What surface finishes work on 50CrMo4 +QT?
Not anodizable; protect with black oxide, manganese phosphate, zinc or hard chrome plating, or gas nitride (Q&T ≥ tempering above 550 °C) — bake at 190–220 °C after plating to avoid hydrogen embrittlement.
Can 50CrMo4 +QT be formed, bent or molded?
Hot form/forge 1100→850 °C with slow cooling in furnace or ash; cold bending or heading is not practical — use annealed stock and small strains only.
What is the maximum service temperature of 50CrMo4 +QT?
50CrMo4 +QT 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 50CrMo4 +QT and 50CrMo4-IH?
+QT is the default condition — standard stocked condition: oil/polymer quench from ~840 °C, temper 540–680 °C for balanced strength and toughness. IH: best choice for journals, spline flanks and hydraulic rods needing surface wear plus tough core. Yield strength is 850 MPa in +QT versus 850 MPa in IH.
Sources
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- EN 10250-3 Open die steel forgings — Alloy special steels — CEN (1999)
- GB/T 3077 (50CrMo equivalent) — SAC (2015)
- 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)
- Cr-Mo quenched and tempered steel 1.7228 datasheet — European special steel producers (Böhler / Deutsche Edelstahlwerke class 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.