Steel 100CrMnSi6-4 +AR (Hot rolled)
Heat-treated state
EN 100CrMnSi6-4 · GB GCr15SiMn
Cheapest mill condition for forging or re-rolling stock; must be spheroidized before machining.
Values for the +AR condition
Other 100CrMnSi6-4 tempers and conditions
100CrMnSi6-4 is listed in 6 conditions; see the grade overview at 100CrMnSi6-4.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ACDefault Spheroidize annealed | Standard stocked bar/tube condition: soft, machinable, ready for turning and subsequent hardening. | 430 | 700 | 18 | 195 HB | 43 W/m·K |
+ARThis page Hot rolled | Cheapest mill condition for forging or re-rolling stock; must be spheroidized before machining. | 520 | 950 | 12 | 29 HRC | 7 % IACS |
Spheroidize annealed and cold drawn | Choose for close-tolerance bright bar and wire for cold-formed or automatic-lathe bearing parts. | 660 | 830 | 9 | 240 HB | — |
Hardened and higher-temperature tempered | Pick when the part sees 150–200 °C service and dimensional stability matters more than peak hardness. | 1,750 | 2,000 | 2 | 60 HRC | — |
Bainite hardened | Used for large or shock-loaded rings and railway bearings: residual compressive stress, better toughness and crack resistance than martensitic hardening. | 1,750 | 2,050 | 3 | 60 HRC | — |
Hardened and tempered | Final service condition for rings, balls and rollers: maximum hardness, wear and rolling-contact fatigue life. | 1,900 | 2,200 | 1 | 62 HRC | 35 W/m·K |
What is 100CrMnSi6-4 +AR?
100CrMnSi6-4 +AR is 100CrMnSi6-4 heat treated to +AR — cheapest mill condition for forging or re-rolling stock; must be spheroidized before machining. 100CrMnSi6-4 +AR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 67% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi). 100CrMnSi6-4 +AR has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,400°C (2,552 °F). +AC is the default condition FabDigit quotes; +AR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Difficult to weld — 8/100, worse than 99% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to machine — 30/100, worse than 89% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
100CrMnSi6-4 +AR properties
Typical room-temperature values for 100CrMnSi6-4 +AR; 23 are specific to this condition. Other listed values are 100CrMnSi6-4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
100CrMnSi6-4 +AR has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
100CrMnSi6-4 +AR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 67% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
100CrMnSi6-4 +AR is rated for continuous service to 200°C (392 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 62% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
100CrMnSi6-4 +AR conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 100CrMnSi6-4 +AR takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
100CrMnSi6-4 +AR's machinability is poor (30/100, worse than 89% of steel grades); weldability not recommended (8/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 100CrMnSi6-4 +AR
Is 100CrMnSi6-4 easy to machine?
Machine only in the spheroidized state with sharp carbide tooling and rigid setups; hardened 60+ HRC parts require CBN hard turning or grinding, and finishing is normally by grinding/honing/superfinishing.
Can 100CrMnSi6-4 be welded?
Essentially not weldable — the ~1 %C composition cracks readily; if repair welding is unavoidable, preheat 300–400 °C, use low-hydrogen filler and immediately re-anneal.
Can 100CrMnSi6-4 be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and mandatory spheroidize anneal (780–810 °C, slow cool) afterwards; cold heading/rolling only from fully spheroidized bar.
What surface finishes work on 100CrMnSi6-4?
No anodizing; protect with oil, phosphate, black oxide, zinc or thin dense chrome — surfaces polish and superfinish extremely well to Ra < 0.05 µm.
100CrMnSi6-4 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 |
|---|---|---|
| CISO 683-17 / GB/T 18254 | 0.93 – 1.05 | 0.99 |
| Si | 0.45 – 0.75 | 0.6 |
| Mn | 0.95 – 1.25 | 1.1 |
| Cr | 1.4 – 1.65 | 1.5 |
| Moresidual | ≤ 0.1 | — |
| Niresidual | ≤ 0.25 | — |
| Curesidual | ≤ 0.25 | — |
| P | ≤ 0.03 | — |
| S≤0.015 for premium bearing quality | ≤ 0.03 | — |
| Ototal oxygen, bearing cleanliness requirement | ≤ 0 | — |
| Fe | balance | — |
100CrMnSi6-4 +AR — frequently asked
What is 100CrMnSi6-4 +AR used for?
100CrMnSi6-4 +AR is typically used for large bearing rings, heavy-duty rollers and rolling mill bearings. In short: GCr15SiMn equivalent; deep-hardening bearing steel; superfinishes below Ra 0.05 µm.
What is the yield strength of 100CrMnSi6-4 +AR?
100CrMnSi6-4 +AR has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 100CrMnSi6-4 +AR easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Machine only in the spheroidized state with sharp carbide tooling and rigid setups; hardened 60+ HRC parts require CBN hard turning or grinding, and finishing is normally by grinding/honing/superfinishing.
Can 100CrMnSi6-4 +AR be welded?
Not readily — weldability is rated not recommended (8/100). Essentially not weldable — the ~1 %C composition cracks readily; if repair welding is unavoidable, preheat 300–400 °C, use low-hydrogen filler and immediately re-anneal.
What surface finishes work on 100CrMnSi6-4 +AR?
No anodizing; protect with oil, phosphate, black oxide, zinc or thin dense chrome — surfaces polish and superfinish extremely well to Ra < 0.05 µm.
Can 100CrMnSi6-4 +AR be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and mandatory spheroidize anneal (780–810 °C, slow cool) afterwards; cold heading/rolling only from fully spheroidized bar.
What is the maximum service temperature of 100CrMnSi6-4 +AR?
100CrMnSi6-4 +AR 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.
Sources
- ISO 683-17 Heat-treatable steels — Ball and roller bearing steels — ISO (2014)
- DIN EN ISO 683-17 / Werkstoff 1.3520 designation — DIN (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (bearing steels) — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (high-carbon bearing steels) — ASM International (1991)
- Bearing steel bar 100Cr6 / 100CrMnSi6-4 data sheets — Ovako / Sandvik / (2023)
- GCr15SiMn — Mysteel / 1688 (2026)
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.