Steel G20CrMo
G20CrMo is a low-carbon chromium-molybdenum case-hardening bearing steel used for large, heavily loaded bearing rings and rollers where a hard wear-resistant surface must sit on a tough core.
Reference datasheet — G20CrMo is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the A condition
G20CrMo tempers and conditions
G20CrMo is supplied in 7 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Order the GB/T 3203 delivery condition, ≤197 HB with uniform structure, for turning bearing rings and as the starting point for carburizing. | 380 | 600 | 24 | 180 HB | — |
Normalized | Normalize after forging to refine grain and remove banded structure at 200 HB; use it as the preliminary heat treatment before carburizing. | 440 | 680 | 22 | 200 HB | 7.8 % IACS |
Hot rolled | Take as-rolled bar as the lowest-cost stock for forging bearing ring blanks; the 210 HB as-rolled structure is not suited to direct machining. | 450 | 700 | 20 | 210 HB | 7.8 % IACS |
Cold drawn | Choose the annealed-and-drawn bright bar for small rings and pins turned on automatic lathes, where tight size tolerance and good surface finish matter more than formability. | 600 | 720 | 12 | 215 HB | 7.8 % IACS |
Quenched and tempered | Pick oil quenched and tempered stock for non-carburized high strength-and-toughness parts such as cages and journals: 730 MPa yield, 285 HB, service to 450 °C. | 730 | 950 | 14 | 30 HRC | — |
Carburized part | Use these 30–45 HRC core values to verify load capacity and toughness beneath the carburized case; it is design data, not an independently orderable delivery condition. | 850 | 1,150 | 12 | 37 HRC | 7.5 % IACS |
Carburized, quenched & low-temperature tempered | Specify carburized, quenched and low-temperature tempered parts as the final service state for rings and rollers: a 60 HRC wear-resistant case over a tough core, but machinability drops to 12. | 950 | 1,200 | 10 | 60 HRC | — |
What is G20CrMo?
G20CrMo is a low-carbon chromium-molybdenum case-hardening bearing steel used for large, heavily loaded bearing rings and rollers where a hard wear-resistant surface must sit on a tough core. In the annealed condition it gives about 380 MPa yield, 600 MPa tensile and 24% elongation at 180 HB, machines well (score 60) and forms readily (score 60), and is supplied as hot-rolled bar, forged ring blanks and tube. It has no corrosion resistance and requires oil or a protective coating, and service is limited to about 400 °C. G20CrNiMo is the nearest alternative when deeper case hardness and higher core toughness are required. G20CrMo 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). G20CrMo has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 68% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
What is G20CrMo used for?
- Large roller bearings
- Wind turbine main bearings
- Mining equipment bearings
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
G20CrMo properties
Typical room-temperature values for G20CrMo-A; bars are the position among steel grades.
Physical3
G20CrMo 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
G20CrMo has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 68% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G20CrMo 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 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
G20CrMo 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 G20CrMo takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability8
G20CrMo's machinability is good (60/100, better than 83% of steel grades); weldability good (65/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. G20CrMo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with G20CrMo
Is G20CrMo easy to machine?
Turn rings in the annealed condition (≤197 HB) with coated carbide at normal speeds and feeds. After carburizing and quenching only grinding or CBN hard turning is practical, so leave 0.3–0.5 mm grinding stock.
Can G20CrMo be welded?
Carbon equivalent is low, but the Cr-Mo content calls for 100–200 °C preheat, low-hydrogen consumables and prompt stress relief. Do not weld in carburized areas.
Can G20CrMo be formed, bent or molded?
Hot forge ring blanks at roughly 1150–850 °C, then normalize and spheroidize anneal. Cold heading and cold extrusion are limited to small-diameter annealed bar.
G20CrMo 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 | 0.17 – 0.23 | 0.2 |
| Si | 0.2 – 0.35 | 0.27 |
| Mn | 0.65 – 0.95 | 0.8 |
| Cr | 0.35 – 0.65 | 0.5 |
| Mo | 0.08 – 0.15 | 0.11 |
| Niresidual element | ≤ 0.3 | |
| Curesidual element | ≤ 0.25 | |
| Pimpurity maximum | ≤ 0.03 | |
| Simpurity maximum | ≤ 0.03 | |
| Obearing steel oxygen control, 15 ppm max | ≤ 0 | |
| Fe | balance |
What surface finishes work on G20CrMo?
Cannot be anodized; protect non-working surfaces with black oxide, phosphate, zinc plating or zinc-flake coating. Raceways are ground and superfinished after hardening to Ra 0.05–0.2 µm and sealed with oil.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
How much does G20CrMo cost?
G20CrMo is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
G20CrMo — frequently asked
What is G20CrMo used for?
G20CrMo is typically used for large roller bearings, wind turbine main bearings and mining equipment bearings. In short: economical carburizing bearing steel; hard case, tough core; good annealed machinability.
What is the yield strength of G20CrMo?
G20CrMo has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is G20CrMo easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Turn rings in the annealed condition (≤197 HB) with coated carbide at normal speeds and feeds. After carburizing and quenching only grinding or CBN hard turning is practical, so leave 0.3–0.5 mm grinding stock.
Can G20CrMo be welded?
Yes — weldability is rated good (65/100). Carbon equivalent is low, but the Cr-Mo content calls for 100–200 °C preheat, low-hydrogen consumables and prompt stress relief. Do not weld in carburized areas.
What surface finishes work on G20CrMo?
Cannot be anodized; protect non-working surfaces with black oxide, phosphate, zinc plating or zinc-flake coating. Raceways are ground and superfinished after hardening to Ra 0.05–0.2 µm and sealed with oil.
Can G20CrMo be formed, bent or molded?
Hot forge ring blanks at roughly 1150–850 °C, then normalize and spheroidize anneal. Cold heading and cold extrusion are limited to small-diameter annealed bar.
What is the maximum service temperature of G20CrMo?
G20CrMo 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 G20CrMo-A and G20CrMo-CH58?
A is the default condition — order the GB/T 3203 delivery condition, ≤197 HB with uniform structure, for turning bearing rings and as the starting point for carburizing. CH58: specify carburized, quenched and low-temperature tempered parts as the final service state for rings and rollers: a 60 HRC wear-resistant case over a tough core, but machinability drops to 12. Yield strength is 380 MPa in A versus 950 MPa in CH58.
How much does G20CrMo cost?
G20CrMo is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.