Steel G20CrMo CH-CORE
Hardness band
CH-CORE = 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.
Values for the CH-CORE condition
Other G20CrMo tempers and conditions
G20CrMo is listed in 7 conditions; see the grade overview at G20CrMo.
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 | — |
CH-COREThis page 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 CH-CORE?
G20CrMo CH-CORE is G20CrMo heat treated to CH-CORE — 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. G20CrMo CH-CORE has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 88% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi). G20CrMo CH-CORE 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). A is the default condition FabDigit quotes; CH-CORE is available on request or by drawing note.
Advantages
- High strength — 850 MPa (123 ksi), better than 88% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Limited formability — 12/100, worse than 92% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to machine — 35/100, worse than 84% of steel grades
G20CrMo CH-CORE properties
Typical room-temperature values for G20CrMo CH-CORE; 22 are specific to this condition. Other listed values are G20CrMo reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G20CrMo CH-CORE 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 CH-CORE has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 88% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G20CrMo CH-CORE is rated for continuous service to 150°C (302 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
G20CrMo CH-CORE conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of G20CrMo CH-CORE 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 CH-CORE's machinability is fair (35/100, worse than 84% of steel grades); weldability poor (30/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G20CrMo CH-CORE
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.
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.
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 | — |
G20CrMo CH-CORE — frequently asked
What is G20CrMo CH-CORE used for?
G20CrMo CH-CORE 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 CH-CORE?
G20CrMo CH-CORE has a typical yield strength of 850 MPa (123 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 88% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is G20CrMo CH-CORE easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% 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 CH-CORE be welded?
Not readily — weldability is rated poor (30/100). 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 CH-CORE?
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 CH-CORE 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 CH-CORE?
G20CrMo CH-CORE is rated for continuous use to about 150°C (302 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.