Steel GCr15 Hot Rolled
Finish state
GB GCr15 · AISI/SAE 52100 · EN 100Cr6 · JIS SUJ2
Cheapest mill form for parts that will be re-heat-treated; hardness and structure are non-uniform, machining is poor.
Values for the Hot Rolled condition
Other GCr15 tempers and conditions
GCr15 is listed in 7 conditions; see the grade overview at GCr15.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize annealed bar/tube | Standard as-supplied condition for bar, tube and wire: soft, uniform globular carbide structure for machining, cold forming and subsequent hardening. | 420 | 700 | 22 | 195 HB | — |
Hot RolledThis page as-rolled bar/plate | Cheapest mill form for parts that will be re-heat-treated; hardness and structure are non-uniform, machining is poor. | 550 | 900 | 12 | 25 HRC | 7.1 % IACS |
900–920 °C air cool (pre-treatment before spheroidizing) | Intermediate mill condition used to break up carbide networks/banding in forgings before spheroidize annealing; too hard for finish machining. | 650 | 1,100 | 10 | 34 HRC | 7 % IACS |
cold drawn annealed bar/wire, bright finish | Pick for precise diameter, bright surface and higher strength on small bar/wire (ball and roller blanks) prior to hardening. | 650 | 850 | 10 | 22 HRC | 7.2 % IACS |
Q&T high temper | Used for gauge bodies, mandrels and shafts where machinability and toughness matter more than maximum wear resistance. | 1,250 | 1,450 | 7 | 44 HRC | — |
Q&T 200–250 °C temper | Choose when slightly lower hardness with better toughness and dimensional stability up to ~200 °C is needed (rollers, cams, heavy shock). | 1,650 | 1,950 | 2 | 58 HRC | — |
Quenched and tempered | Final bearing condition: maximum hardness, wear and rolling-contact fatigue resistance; brittle, service limited to ~150 °C. | 1,800 | 2,200 | 1 | 62 HRC | — |
What is GCr15 Hot Rolled?
GCr15 Hot Rolled is GCr15 supplied in the Hot Rolled condition — cheapest mill form for parts that will be re-heat-treated; hardness and structure are non-uniform, machining is poor. GCr15 Hot Rolled has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi). GCr15 Hot Rolled has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Hot Rolled is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Low fracture toughness — 35 MPa·√m (31.9 ksi·√in), worse than 94% of steel grades
- Difficult to machine — 30/100, worse than 89% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
GCr15 Hot Rolled properties
Typical room-temperature values for GCr15 Hot Rolled; 22 are specific to this condition. Other listed values are GCr15 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GCr15 Hot Rolled has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
GCr15 Hot Rolled has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
GCr15 Hot Rolled is rated for continuous service to 150°C (302 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
GCr15 Hot Rolled conducts electricity at 7.1 % IACS, worse than 72% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of GCr15 Hot Rolled 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
GCr15 Hot Rolled's machinability is poor (30/100, worse than 89% of steel grades); weldability not recommended (12/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GCr15 Hot Rolled
Is GCr15 easy to machine?
Machine in the spheroidized annealed condition (~195 HB) with carbide tools and rigid setups; hardened 60+ HRC parts require CBN hard turning or grinding.
Can GCr15 be welded?
Essentially unweldable in structural terms — 1 % C promotes quench cracking; if unavoidable, preheat 300–400 °C, low-hydrogen filler and immediate stress relief/temper.
Can GCr15 be formed, bent or molded?
Cold heading and ball blanking are done on spheroidized stock; hot forge 1050–1150 °C and cool slowly to avoid carbide network and flake cracking.
What surface finishes work on GCr15?
Grind and superfinish raceways; protect with oil, phosphate or black oxide (chrome/nickel plating needs bake-out to avoid hydrogen embrittlement).
GCr15 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 |
|---|---|---|
| CGB/T 18254 | 0.95 – 1.05 | 1 |
| Cr | 1.4 – 1.65 | 1.5 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.25 – 0.45 | 0.35 |
| Niresidual | ≤ 0.25 | — |
| Curesidual | ≤ 0.25 | — |
| Moresidual | ≤ 0.1 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| O12 ppm max, high-quality bearing steel | ≤ 0 | — |
| Fe | balance | — |
GCr15 Hot Rolled — frequently asked
What is GCr15 Hot Rolled used for?
GCr15 Hot Rolled is typically used for ball bearing rings and balls, roller and needle bearing races, precision machine-tool spindle bearings, cam followers and track rollers, hydraulic pump plungers and pistons and die and punch bushings. In short: bearing Cr-bearing steel.
What is the yield strength of GCr15 Hot Rolled?
GCr15 Hot Rolled has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is GCr15 Hot Rolled easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Machine in the spheroidized annealed condition (~195 HB) with carbide tools and rigid setups; hardened 60+ HRC parts require CBN hard turning or grinding.
Can GCr15 Hot Rolled be welded?
Not readily — weldability is rated not recommended (12/100). Essentially unweldable in structural terms — 1 % C promotes quench cracking; if unavoidable, preheat 300–400 °C, low-hydrogen filler and immediate stress relief/temper.
What surface finishes work on GCr15 Hot Rolled?
Grind and superfinish raceways; protect with oil, phosphate or black oxide (chrome/nickel plating needs bake-out to avoid hydrogen embrittlement).
Can GCr15 Hot Rolled be formed, bent or molded?
Cold heading and ball blanking are done on spheroidized stock; hot forge 1050–1150 °C and cool slowly to avoid carbide network and flake cracking.
What is the maximum service temperature of GCr15 Hot Rolled?
GCr15 Hot Rolled 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.
Can FabDigit make parts in GCr15 Hot Rolled?
Yes — GCr15 Hot Rolled is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A295 / A295M High-Carbon Anti-Friction Bearing Steel — ASTM (2014)
- ISO 683-17 / DIN EN ISO 683-17 (100Cr6) — ISO (2014)
- JIS G 4805 (SUJ2) — JISC (2019)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 Fatigue and Fracture — ASM International (1996)
- 100Cr6 / 52100 bearing steel bar datasheet — Ovako / Sandvik (2021)
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.