Steel GCr15SiMn-MQ
Heat-treated state
EN 100CrMn6
MQ = martempered () + temper, 60-63 HRC
Choose salt-bath martempering plus tempering for thin-wall, large-diameter rings where distortion and quench cracking must be limited, with 61 HRC close to direct quenching.
Values for the MQ condition
Other GCr15SiMn tempers and conditions
GCr15SiMn is listed in 9 conditions; see the grade overview at GCr15SiMn.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Order the standard supply condition — fine spheroidal carbides at 195 HB — for turning, cold extrusion and as preparation for final hardening. | 420 | 750 | 22 | 195 HB | — |
Normalized | Normalize after forging to break up carbide networks and refine grain at 300 HB; treat it as a pre-treatment before spheroidize annealing, not a machining condition. | 560 | 980 | 12 | 31 HRC | 7.5 % IACS |
Hot rolled | Take the as-rolled or as-forged blank only as raw stock; hardness reaches 330 HB and is uneven, so spheroidize annealing is required before machining. | 620 | 1,050 | 10 | 35 HRC | 7.5 % IACS |
Cold drawn | Choose annealed-then-cold-drawn bar for close size and good surface when machining small roller and pin blanks directly, accepting 240 HB and low formability. | 700 | 880 | 10 | 22 HRC | 7.5 % IACS |
Q&T stabilized S1 | Pick the ~250 °C stabilizing temper for bearings running to about 200 °C where dimensional stability outranks hardness; 57 HRC reduces hardness and fatigue life. | 1,750 | 2,000 | 3 | 57 HRC | 6 % IACS |
Q&T 61-64 HRC | Specify the standard finished-bearing route — oil quench from 820–840 °C plus 150–180 °C temper — for peak 62 HRC and contact fatigue life in rings and rollers up to 120 °C. | 1,900 | 2,300 | 1 | 62 HRC | 36 W/m·K |
MQThis page Martempered () + temper, 60-63 HRC | Choose salt-bath martempering plus tempering for thin-wall, large-diameter rings where distortion and quench cracking must be limited, with 61 HRC close to direct quenching. | 1,950 | 2,250 | 1 | 61 HRC | 5.6 % IACS |
Q&T 58-61 HRC | Use the higher 200–230 °C temper on large or heavily loaded rings, trading a little hardness (59 HRC) for toughness and dimensional stability up to 150 °C. | — | 2,150 | — | 59 HRC | — |
Austempered to lower bainite, 58-62 HRC | Austemper to lower bainite at 58–62 HRC when impact, contaminated lubrication or high compressive surface stress govern — rolling mill, railway and shock-loaded bearings. | — | 2,200 | — | 60 HRC | — |
What is GCr15SiMn-MQ?
GCr15SiMn-MQ is GCr15SiMn heat treated to MQ — choose salt-bath martempering plus tempering for thin-wall, large-diameter rings where distortion and quench cracking must be limited, with 61 HRC close to direct quenching. GCr15SiMn-MQ has a yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,250 MPa (326 ksi) — stronger than 100% of steel grades. Elongation at break is 1% and the elastic modulus is 208 GPa (30.2 Msi). GCr15SiMn-MQ 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). A is the default condition FabDigit quotes; MQ is available on request or by drawing note.
Advantages
- High strength — 1,950 MPa (283 ksi), better than 100% of steel grades
- Polishes to a fine finish — 88/100, better than 100% of steel grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 100% of steel grades
- Difficult to machine — 8/100, worse than 100% of steel grades
- Difficult to weld — 2/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Limited ductility — 1%, worse than 99% of steel grades
GCr15SiMn-MQ properties
Typical room-temperature values for GCr15SiMn-MQ; 22 are specific to this condition. Other listed values are GCr15SiMn reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GCr15SiMn-MQ 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
GCr15SiMn-MQ has a yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,250 MPa (326 ksi) — stronger than 100% of steel grades. Elongation at break is 1% and the elastic modulus is 208 GPa (30.2 Msi).
Thermal6
GCr15SiMn-MQ is rated for continuous service to 120°C (248 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
GCr15SiMn-MQ conducts electricity at 5.6 % IACS, worse than 80% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of GCr15SiMn-MQ takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
GCr15SiMn-MQ's machinability is not recommended (8/100, worse than 100% of steel grades); weldability not recommended (2/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GCr15SiMn-MQ
Is GCr15SiMn easy to machine?
Turn, mill and drill only in the spheroidise-annealed condition (≤229 HB); after hardening restrict work to grinding, CBN hard turning or EDM, and flood-cool grinding to prevent burn and grinding cracks.
Can GCr15SiMn be welded?
With about 1 % C the weldability is very poor and welding should be avoided in principle; if repair is unavoidable, preheat 300–400 °C, use low-hydrogen or nickel-based filler and temper immediately.
Can GCr15SiMn be formed, bent or molded?
In the annealed condition it takes warm upsetting, ring rolling and cold extrusion into raceway blanks; forge at about 1050–1120 °C, finish no lower than 850 °C, then slow-cool plus normalise/spheroidise anneal to break up carbide networks.
What surface finishes work on GCr15SiMn?
Cannot be anodised. Raceways are precision ground and superfinished to a mirror surface, while non-working surfaces are usually black oxided, phosphated, chrome plated or oiled for storage.
GCr15SiMn 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 | 0.95 – 1.05 | 1 |
| Siabove GCr15; raises hardenability and temper stability | 0.45 – 0.75 | 0.6 |
| Mnmarkedly increases hardenability | 0.95 – 1.25 | 1.1 |
| Cr | 1.4 – 1.65 | 1.5 |
| Niresidual element | ≤ 0.3 | — |
| Curesidual element; Cu+Ni less than or equal to 0.50 | ≤ 0.25 | — |
| Moresidual element | ≤ 0.1 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Ooxygen 12 ppm max (quality/high-grade bearing steel) | ≤ 0 | — |
| Fe | balance | — |
GCr15SiMn-MQ — frequently asked
What is GCr15SiMn-MQ used for?
GCr15SiMn-MQ is typically used for large rolling bearings, heavy machinery rollers and rail bearings. In short: higher hardenability than GCr15; heavy-section bearing rings; grind-and-superfinish only.
What is the yield strength of GCr15SiMn-MQ?
GCr15SiMn-MQ has a typical yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,250 MPa (326 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is GCr15SiMn-MQ easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of steel grades). Turn, mill and drill only in the spheroidise-annealed condition (≤229 HB); after hardening restrict work to grinding, CBN hard turning or EDM, and flood-cool grinding to prevent burn and grinding cracks.
Can GCr15SiMn-MQ be welded?
Not readily — weldability is rated not recommended (2/100). With about 1 % C the weldability is very poor and welding should be avoided in principle; if repair is unavoidable, preheat 300–400 °C, use low-hydrogen or nickel-based filler and temper immediately.
What surface finishes work on GCr15SiMn-MQ?
Cannot be anodised. Raceways are precision ground and superfinished to a mirror surface, while non-working surfaces are usually black oxided, phosphated, chrome plated or oiled for storage.
Can GCr15SiMn-MQ be formed, bent or molded?
In the annealed condition it takes warm upsetting, ring rolling and cold extrusion into raceway blanks; forge at about 1050–1120 °C, finish no lower than 850 °C, then slow-cool plus normalise/spheroidise anneal to break up carbide networks.
What is the maximum service temperature of GCr15SiMn-MQ?
GCr15SiMn-MQ is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between GCr15SiMn-A and GCr15SiMn-MQ?
A is the default condition — order the standard supply condition — fine spheroidal carbides at 195 HB — for turning, cold extrusion and as preparation for final hardening. MQ: choose salt-bath martempering plus tempering for thin-wall, large-diameter rings where distortion and quench cracking must be limited, with 61 HRC close to direct quenching. Yield strength is 420 MPa in A versus 1,950 MPa in MQ.
Sources
- ISO 683-17 / DIN EN ISO 683-17 (100CrMn6, 1.3520) — ISO (2014)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Bearing steel grades data (100Cr6 / 100CrMn6) heat treatment and properties — Ovako / SKF (2020)
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.