Steel G20CrNiMo Q&T (Quenched and tempered)
Heat-treated state
Direct-hardened condition for shafts, flanges and non-raceway parts machined from the same bearing-steel stock.
Values for the Q&T condition
Other G20CrNiMo tempers and conditions
G20CrNiMo is listed in 7 conditions; see the grade overview at G20CrNiMo.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard GB/T 3203 delivery condition for bearing ring blanks: softest, most uniform structure for turning, boring and cold forming before carburizing. | 400 | 620 | 29 | 190 HB | — |
Normalized | Grain refinement and banding removal on forged rings before carburizing; also used when a tougher machining structure than annealed is wanted. | 430 | 680 | 25 | 14 HRC | 8 % IACS |
Hot rolled | Mill as-rolled bar for forging stock or subsequent heat treatment; hardness too high and non-uniform for finish machining. | 450 | 720 | 22 | 20 HRC | 8 % IACS |
Cold drawn | Small-diameter precision bar for rollers, pins and cages where close tolerance and better surface finish reduce machining allowance. | 620 | 760 | 12 | 22 HRC | 8 % IACS |
Q&TThis page Quenched and tempered | Direct-hardened condition for shafts, flanges and non-raceway parts machined from the same bearing-steel stock. | 850 | 1,080 | 14 | 34 HRC | — |
Carburized and hardened | The functional service condition for bearing rings and rollers: hard, compressively stressed deep case on a tough 30–42 HRC core for shock and heavy contact loads. | 950 | 1,250 | 11 | 61 HRC | — |
Carburized, quenched, sub-zero treated and double tempered | Choose when retained austenite must be minimized for precision bearings and long-term dimensional stability at elevated running temperature. | 1,050 | 1,300 | 11 | 62 HRC | 7 % IACS |
What is G20CrNiMo Q&T?
G20CrNiMo Q&T is G20CrNiMo heat treated to Q&T — direct-hardened condition for shafts, flanges and non-raceway parts machined from the same bearing-steel stock. G20CrNiMo Q&T has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 88% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). G20CrNiMo Q&T 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). A is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 80/100, better than 97% of steel grades
- High strength — 850 MPa (123 ksi), better than 88% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
G20CrNiMo Q&T properties
Typical room-temperature values for G20CrNiMo Q&T; 13 are specific to this condition. Other listed values are G20CrNiMo reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G20CrNiMo Q&T 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).
Mechanical14
G20CrNiMo Q&T has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 88% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G20CrNiMo Q&T is rated for continuous service to 200°C (392 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
G20CrNiMo Q&T 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 G20CrNiMo Q&T takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
G20CrNiMo Q&T's machinability is fair (40/100, worse than 77% of steel grades); weldability fair (50/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G20CrNiMo Q&T
Is G20CrNiMo easy to machine?
Turn/bore in the annealed ≤229 HB condition with carbide inserts and ample coolant; after carburizing only grinding, honing or CBN hard-turning is practical.
Can G20CrNiMo be welded?
Weldable before carburizing with low-hydrogen consumables, 200–300 °C preheat and post-weld temper; never weld a carburized case.
Can G20CrNiMo be formed, bent or molded?
Hot forge 1100–1180 °C with finish above 900 °C then normalize/anneal; cold forming limited to modest upsetting of annealed stock.
What surface finishes work on G20CrNiMo?
Carburize 920–940 °C to the required case depth, quench in oil/press-quench for rings, temper 160–200 °C, then grind and superfinish raceways; protect with phosphating, black oxide or oil film since the steel has no corrosion resistance.
G20CrNiMo 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 |
|---|---|---|
| Clow carbon core for carburizing | 0.17 – 0.23 | 0.2 |
| Si | 0.15 – 0.4 | 0.27 |
| Mn | 0.6 – 0.9 | 0.75 |
| Cr | 0.35 – 0.65 | 0.5 |
| Nicore toughness | 0.4 – 0.7 | 0.55 |
| Mohardenability, temper resistance | 0.15 – 0.3 | 0.22 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Cu | ≤ 0.25 | — |
| O≤15 ppm total oxygen typical for bearing steel | ≤ 0 | — |
| Fe | balance | — |
G20CrNiMo Q&T — frequently asked
What is G20CrNiMo Q&T used for?
G20CrNiMo Q&T is typically used for large industrial bearings, rail and wind turbine bearings and heavy machinery rollers. In short: deep-case carburizing bearing steel; tougher core than G20CrMo; sized for large sections.
What is the yield strength of G20CrNiMo Q&T?
G20CrNiMo Q&T has a typical yield strength of 850 MPa (123 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 88% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is G20CrNiMo Q&T easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Turn/bore in the annealed ≤229 HB condition with carbide inserts and ample coolant; after carburizing only grinding, honing or CBN hard-turning is practical.
Can G20CrNiMo Q&T be welded?
With care — weldability is rated fair (50/100). Weldable before carburizing with low-hydrogen consumables, 200–300 °C preheat and post-weld temper; never weld a carburized case.
What surface finishes work on G20CrNiMo Q&T?
Carburize 920–940 °C to the required case depth, quench in oil/press-quench for rings, temper 160–200 °C, then grind and superfinish raceways; protect with phosphating, black oxide or oil film since the steel has no corrosion resistance.
Can G20CrNiMo Q&T be formed, bent or molded?
Hot forge 1100–1180 °C with finish above 900 °C then normalize/anneal; cold forming limited to modest upsetting of annealed stock.
What is the maximum service temperature of G20CrNiMo Q&T?
G20CrNiMo Q&T is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between G20CrNiMo-A and G20CrNiMo CH-SR?
A is the default condition — standard GB/T 3203 delivery condition for bearing ring blanks: softest, most uniform structure for turning, boring and cold forming before carburizing. CH-SR: choose when retained austenite must be minimized for precision bearings and long-term dimensional stability at elevated running temperature. Yield strength is 400 MPa in A versus 1,050 MPa in CH-SR.
Sources
- GB/T 3203 / (carburizing bearing steel bar) (2016)
- GB/T 3077 (20CrNiMo) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (8620 data) — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing of Ni-Cr-Mo steels) — ASM International (1991)
- 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.