Steel GCr15
GB GCr15 · AISI/SAE 52100 · EN 100Cr6 · JIS SUJ2
GCr15 is a through-hardening high-carbon chromium bearing steel per GB/T 18254, directly equivalent to AISI 52100, 100Cr6 and SUJ2.
Values for the Annealed condition
GCr15 tempers and conditions
GCr15 is supplied in 7 conditions, soft to hard. Annealed 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 |
|---|---|---|---|---|---|---|
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 | — |
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?
GCr15 is a through-hardening high-carbon chromium bearing steel per GB/T 18254, directly equivalent to AISI 52100, 100Cr6 and SUJ2. Supplied spheroidize-annealed at about 195 HB (92 HRB) with 420 MPa yield, 700 MPa tensile and 22 % elongation, it is bought as bar, tube and ring blanks for parts that must be hardened to 60+ HRC with a fine, uniform carbide structure. It has no corrosion resistance, is limited to roughly 400 °C service, and is essentially unweldable. Where weldability or corrosion resistance matters, use 440C or a case-hardening grade such as 20CrMnTi. GCr15 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). GCr15 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
What is GCr15 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
- Die and punch bushings
- Gauge blocks and measuring tool bodies
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Difficult to weld — 15/100, worse than 91% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
GCr15 properties
Typical room-temperature values for GCr15-Annealed; bars are the position among steel grades.
Physical3
GCr15 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 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
GCr15 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
GCr15 conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of GCr15 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's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (15/100); formability fair (40/100).
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. GCr15 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GCr15
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.
Manufacturability
The process limits FabDigit applies to GCr15. Every GCr15 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair45 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Not Recommend40 / 100 |
|---|---|
| Weldability | Poor15 / 100 |
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 |
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).
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel GCr15 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does GCr15 cost?
GCr15 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GCr15 — frequently asked
What is GCr15 used for?
GCr15 is typically used for ball bearing rings and balls, roller and needle bearing races, precision machine-tool spindle bearings, cam followers and track rollers, hydraulic pump plungers and pistons and die and punch bushings. In short: bearing Cr-bearing steel.
What is the yield strength of GCr15?
GCr15 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is GCr15 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the spheroidized annealed condition (~195 HB) with carbide tools and rigid setups; hardened 60+ HRC parts require CBN hard turning or grinding.
Can GCr15 be welded?
Not readily — weldability is rated poor (15/100). Essentially unweldable in structural terms — 1 % C promotes quench cracking; if unavoidable, preheat 300–400 °C, low-hydrogen filler and immediate stress relief/temper.
What surface finishes work on GCr15?
Grind and superfinish raceways; protect with oil, phosphate or black oxide (chrome/nickel plating needs bake-out to avoid hydrogen embrittlement).
Can GCr15 be formed, bent or molded?
Cold heading and ball blanking are done on spheroidized stock; hot forge 1050–1150 °C and cool slowly to avoid carbide network and flake cracking.
What is the maximum service temperature of GCr15?
GCr15 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does GCr15 cost?
GCr15 is a standard-cost steel ($$), cheaper than about 71% 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.
Can FabDigit make parts in GCr15?
Yes — GCr15 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; 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.