Steel 20CrMoV5-7 +QT900
Heat-treated state
EN 20CrMoV5-7
Lower tempering temperature for thin sections where higher strength is needed and service temperature stays below ~450 °C.
Values for the +QT900 condition
Other 20CrMoV5-7 tempers and conditions
20CrMoV5-7 is listed in 8 conditions; see the grade overview at 20CrMoV5-7.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Supply condition for heavy machining, cold forming or before carburising/hardening. | 380 | 640 | 22 | 195 HB | — |
Hot rolled | Cheapest mill condition for parts that will be fully heat treated by the customer. | 450 | 750 | 18 | 21 HRC | 7.8 % IACS |
Normalized | Uniform fine-grained structure for forgings and as a pre-treatment before quench and temper. | 470 | 760 | 19 | 20 HRC | 7.9 % IACS |
Cold drawn | Bright, close-tolerance bar for automatic machining where full Q&T properties are not required. | 660 | 800 | 10 | 22 HRC | 7.8 % IACS |
+QT800Default quenched and tempered, Rm 800–950 MPa | Standard stocked condition: best strength/toughness balance for shafts, gears and elevated-temperature bolting; also the base state before nitriding. | 700 | 880 | 16 | 27 HRC | — |
+QT + gas nitrided | Choose when wear and scuffing resistance plus low distortion are needed; core keeps Q&T strength. | 700 | 880 | 14 | 62 HRC | — |
Carburized and hardened | Use for heavily loaded gear teeth needing a deep, very hard case with a tough low-carbon core. | 800 | 1,100 | 10 | 60 HRC | 7.2 % IACS |
+QT900This page quenched and tempered, Rm 900–1100 MPa (small sections) | Lower tempering temperature for thin sections where higher strength is needed and service temperature stays below ~450 °C. | 830 | 1,000 | 13 | 33 HRC | — |
What is 20CrMoV5-7 +QT900?
20CrMoV5-7 +QT900 is 20CrMoV5-7 heat treated to +QT900 — lower tempering temperature for thin sections where higher strength is needed and service temperature stays below ~450 °C. 20CrMoV5-7 +QT900 has a yield strength of 830 MPa (120 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 87% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi). 20CrMoV5-7 +QT900 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). +QT800 is the default condition FabDigit quotes; +QT900 is available on request or by drawing note.
Advantages
- High strength — 830 MPa (120 ksi), better than 87% of steel grades
Limitations
- Difficult to machine — 38/100, worse than 80% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
20CrMoV5-7 +QT900 properties
Typical room-temperature values for 20CrMoV5-7 +QT900; 11 are specific to this condition. Other listed values are 20CrMoV5-7 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20CrMoV5-7 +QT900 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
20CrMoV5-7 +QT900 has a yield strength of 830 MPa (120 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 87% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20CrMoV5-7 +QT900 is rated for continuous service to 430°C (806 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
20CrMoV5-7 +QT900 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of 20CrMoV5-7 +QT900 takes about 31 MJ of energy and emits 2.2 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability5
20CrMoV5-7 +QT900's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (40/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20CrMoV5-7 +QT900
Is 20CrMoV5-7 easy to machine?
Rough machine in the annealed state; in Q&T condition use rigid setups, coated carbide at moderate speed and finish-grind after nitriding/carburising since the case is not economically machinable.
Can 20CrMoV5-7 be welded?
Weldable with matching low-alloy Cr-Mo-V consumables using 250–350 °C preheat, controlled interpass and PWHT at 650–700 °C; avoid welding after nitriding.
Can 20CrMoV5-7 be formed, bent or molded?
Hot forge at about 1100→850 °C with slow cooling and subsequent normalising or annealing; cold forming only in the soft-annealed state and only for modest deformation.
What surface finishes work on 20CrMoV5-7?
No anodising (ferrous); protect with phosphating and oil, zinc/nickel plating (bake to avoid hydrogen embrittlement above 1000 MPa), black oxide or paint — nitrided surfaces should be left unplated.
20CrMoV5-7 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 |
|---|---|---|
| Ccase-hardening/nitriding carbon level | 0.17 – 0.23 | 0.2 |
| Si | 0.15 – 0.4 | 0.25 |
| Mn | 0.4 – 0.8 | 0.6 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Crhardenability + nitride former | 1.2 – 1.5 | 1.35 |
| Motemper embrittlement resistance, creep strength | 0.5 – 0.7 | 0.6 |
| Vgrain refinement, secondary hardening | 0.2 – 0.35 | 0.28 |
| Fe | balance | — |
20CrMoV5-7 +QT900 — frequently asked
What is 20CrMoV5-7 +QT900 used for?
20CrMoV5-7 +QT900 is typically used for nitrided gears, camshafts, high-wear shafts and valve components. In short: nitriding Cr-Mo-V gear steel; hard case, tough core; usable to 500 °C.
What is the yield strength of 20CrMoV5-7 +QT900?
20CrMoV5-7 +QT900 has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 87% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 20CrMoV5-7 +QT900 easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Rough machine in the annealed state; in Q&T condition use rigid setups, coated carbide at moderate speed and finish-grind after nitriding/carburising since the case is not economically machinable.
Can 20CrMoV5-7 +QT900 be welded?
With care — weldability is rated fair (40/100). Weldable with matching low-alloy Cr-Mo-V consumables using 250–350 °C preheat, controlled interpass and PWHT at 650–700 °C; avoid welding after nitriding.
What surface finishes work on 20CrMoV5-7 +QT900?
No anodising (ferrous); protect with phosphating and oil, zinc/nickel plating (bake to avoid hydrogen embrittlement above 1000 MPa), black oxide or paint — nitrided surfaces should be left unplated.
Can 20CrMoV5-7 +QT900 be formed, bent or molded?
Hot forge at about 1100→850 °C with slow cooling and subsequent normalising or annealing; cold forming only in the soft-annealed state and only for modest deformation.
What is the maximum service temperature of 20CrMoV5-7 +QT900?
20CrMoV5-7 +QT900 is rated for continuous use to about 430°C (806 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20CrMoV5-7 +QT800 and 20CrMoV5-7-CH?
+QT800 is the default condition — standard stocked condition: best strength/toughness balance for shafts, gears and elevated-temperature bolting; also the base state before nitriding. CH: use for heavily loaded gear teeth needing a deep, very hard case with a tough low-carbon core. Yield strength is 700 MPa in +QT800 versus 800 MPa in CH.
Sources
- EN 10085 — Nitriding steels: technical delivery conditions — CEN (2001)
- EN 10269 — Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties — CEN (2013)
- EN 10083-3 — Steels for quenching and tempering: alloy steels — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4A/4D — Heat Treating of Irons and Steels — ASM International (2013)
- Cr-Mo-V nitriding/case-hardening steel bar datasheets — Böhler / Ovako / Dörrenberg (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.