Steel 100Cr6 · hardness band
Steel 100Cr6 Q&T 250
Properties of the Q&T 250 condition, compared with the other 100Cr6 tempers.
Choose when parts must run warm (to ~200 °C) or need extra toughness and dimensional stability at some loss of hardness.
What is 100Cr6 Q&T 250?
100Cr6 Q&T 250 is 100Cr6 heat treated to Q&T 250 — choose when parts must run warm (to ~200 °C) or need extra toughness and dimensional stability at some loss of hardness. 100Cr6 Q&T 250 has a yield strength of 1,700 MPa (247 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 99% of steel grades. Elongation at break is 3% and the elastic modulus is 210 GPa (30.5 Msi). 100Cr6 Q&T 250 has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,424°C (2,595 °F). Annealed is the default condition FabDigit quotes; Q&T 250 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 100% of steel grades
- High strength — 1,700 MPa (247 ksi), better than 99% of steel grades
Limitations
- Limited ductility — 3%, worse than 99% of steel grades
- Difficult to machine — 12/100, worse than 99% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
100Cr6 Q&T 250 properties
Typical room-temperature values for 100Cr6 Q&T 250 — 10 properties are specific to this condition; the rest are grade-level values shared by every 100Cr6 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
100Cr6 Q&T 250 has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,424°C (2,595 °F).
Mechanical14
100Cr6 Q&T 250 has a yield strength of 1,700 MPa (247 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 99% of steel grades. Elongation at break is 3% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
100Cr6 Q&T 250 is rated for continuous service to 200°C (392 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
100Cr6 Q&T 250 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 100Cr6 Q&T 250 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
100Cr6 Q&T 250's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (12/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 100Cr6 tempers and conditions
100Cr6 is also supplied in 8 other conditions. The full side-by-side table is on the 100Cr6 overview.
- AnnealedDefaultStandard stock condition: uniform spheroidized carbides for best machinability, cold forming and subsequent hardening response.420 MPa yield · 200 HB
- Q&TStandard bearing/tool condition: maximum hardness, wear and rolling-contact fatigue life; use below ~120–150 °C to keep dimensional stability.1,900 MPa yield · 62 HRC
- BHPick for higher toughness, compressive surface stresses and better resistance to contamination/impact loading in bearings and rings.1,800 MPa yield · 60 HRC
- Q&T 250Choose when parts must run warm (to ~200 °C) or need extra toughness and dimensional stability at some loss of hardness.1,700 MPa yield · 57 HRC
- AC-CSpheroidized bar given a light cold-drawing pass for close tolerance and bright finish; strength and hardness rise, ductility and formability drop versus +AC.600 MPa yield · 225 HB
- HRCheapest bar form for parts that will be fully re-annealed and hardened; hard, poorly machinable lamellar/pearlitic structure as delivered.550 MPa yield · 280 HB
- ACStandard EN ISO 683-17 delivery condition: globular carbides in ferrite, max ~207 HB, optimised for machining and cold forming before hardening.410 MPa yield · 190 HB
Working with 100Cr6 Q&T 250
Is 100Cr6 easy to machine?
Machine only in the spheroidize annealed state (~200 HB) with rigid setups and carbide tooling; hardened 60+ HRC parts require grinding, honing or CBN hard turning.
Can 100Cr6 be welded?
Essentially unweldable in production — 1%C gives severe cracking; if unavoidable, preheat 300–400 °C, use low-hydrogen/austenitic filler and post-weld anneal immediately.
Can 100Cr6 be formed, bent or molded?
Cold heading, drawing and ring rolling are done soft annealed; hot work 850–1050 °C then slow cool and re-spheroidize, and always harden from 830–860 °C with oil/salt quench plus prompt tempering.
What surface finishes work on 100Cr6?
No inherent corrosion protection: finish with oil, phosphate, black oxide, zinc or hard chrome; the fine carbide structure takes a mirror polish and is ideal for superfinished raceways.
100Cr6 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 GCr15: 0.95–1.05 | 0.93 – 1.05 | 1 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.25 – 0.45 | 0.35 |
| Cr | 1.35 – 1.6 | 1.45 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Niresidual, max | ≤ 0.3 | — |
| Curesidual, max | ≤ 0.3 | — |
| Moresidual, max | ≤ 0.1 | — |
| O≤15 ppm for high-cleanliness bearing quality | ≤ 0 | — |
| Fe | balance | — |
100Cr6 Q&T 250 — frequently asked
What is 100Cr6 Q&T 250 used for?
100Cr6 Q&T 250 is typically used for ball bearing rings and balls, cylindrical and taper roller bearing races, ball screw shafts and nuts, linear guide rails and blocks, cam followers and track rollers and precision gauges and gauge blocks. In short: workhorse bearing steel.
What is the yield strength of 100Cr6 Q&T 250?
100Cr6 Q&T 250 has a typical yield strength of 1,700 MPa (247 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 100Cr6 Q&T 250 easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine only in the spheroidize annealed state (~200 HB) with rigid setups and carbide tooling; hardened 60+ HRC parts require grinding, honing or CBN hard turning.
Can 100Cr6 Q&T 250 be welded?
Not readily — weldability is rated not recommended (12/100). Essentially unweldable in production — 1%C gives severe cracking; if unavoidable, preheat 300–400 °C, use low-hydrogen/austenitic filler and post-weld anneal immediately.
What surface finishes work on 100Cr6 Q&T 250?
No inherent corrosion protection: finish with oil, phosphate, black oxide, zinc or hard chrome; the fine carbide structure takes a mirror polish and is ideal for superfinished raceways.
Can 100Cr6 Q&T 250 be formed, bent or molded?
Cold heading, drawing and ring rolling are done soft annealed; hot work 850–1050 °C then slow cool and re-spheroidize, and always harden from 830–860 °C with oil/salt quench plus prompt tempering.
What is the maximum service temperature of 100Cr6 Q&T 250?
100Cr6 Q&T 250 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 100Cr6 Annealed and 100Cr6-BH?
Annealed is the default condition — standard stock condition: uniform spheroidized carbides for best machinability, cold forming and subsequent hardening response. BH: pick for higher toughness, compressive surface stresses and better resistance to contamination/impact loading in bearings and rings. Yield strength is 420 MPa in Annealed versus 1,800 MPa in BH.
Can FabDigit make parts in 100Cr6 Q&T 250?
Yes — 100Cr6 Q&T 250 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN ISO 683-17 Heat-treatable steels — Ball and roller bearing steels — ISO/CEN (2014)
- GB/T 18254 (GCr15) — SAC (2016)
- ASTM A295 High-Carbon Anti-Friction Bearing Steel (52100) — ASTM (2014)
- JIS G 4805 High carbon chromium bearing steels (SUJ2) — JSA (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Bearing steel 100Cr6 / 52100 bar datasheets — Ovako / Sandvik / Böhler (2022)
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.