Steel 100CrMnSi4-4 +A (Annealed)
Heat-treated state · default condition
EN 100CrMnSi4-4
Standard stock condition for bars and tubes: machine or cold-form the part, then harden.
Values for the +A condition
Other 100CrMnSi4-4 tempers and conditions
100CrMnSi4-4 is listed in 6 conditions; see the grade overview at 100CrMnSi4-4.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ADefaultThis page Annealed | Standard stock condition for bars and tubes: machine or cold-form the part, then harden. | 400 | 640 | 20 | 195 HB | 42 W/m·K |
Hot rolled / as-rolled, untreated | Cheapest bar condition for forging or re-rolling stock; must be annealed before machining. | 550 | 950 | 10 | 280 HB | 40 W/m·K |
Cold drawn | Choose for close-tolerance, bright bar and wire feeding automatic lathes or cold-heading of ball/roller blanks. | 600 | 760 | 8 | 20 HRC | 5.7 % IACS |
Hardened + dimensional-stabilising temper (230–260 °C), 57–59 HRC | Pick for bearings running at 150–200 °C where dimensional stability matters more than peak hardness. | 1,750 | 2,050 | 1 | 58 HRC | 34 W/m·K |
Bainite hardened (isothermal transformation ~230 °C), 58–62 HRC | Use for shock-loaded or contaminated-lubrication bearings needing higher toughness and compressive residual stress with almost no retained austenite. | 1,800 | 2,100 | 2 | 60 HRC | — |
Hardened + low temper (160–180 °C), 60–64 HRC | Standard finished-bearing condition: oil quench from ~835–860 °C, temper 160–180 °C for maximum rolling-contact fatigue life. | 1,900 | 2,300 | 0.5 | 62 HRC | 33 W/m·K |
What is 100CrMnSi4-4 +A?
100CrMnSi4-4 +A is 100CrMnSi4-4 heat treated to +A — standard stock condition for bars and tubes: machine or cold-form the part, then harden. 100CrMnSi4-4 +A has a yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi). 100CrMnSi4-4 +A has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,370°C (2,498 °F).
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low electrical conductivity — 5.7 % IACS, worse than 80% of steel grades
100CrMnSi4-4 +A properties
Typical room-temperature values for 100CrMnSi4-4 +A; 14 are specific to this condition. Other listed values are 100CrMnSi4-4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
100CrMnSi4-4 +A has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,370°C (2,498 °F).
Mechanical14
100CrMnSi4-4 +A has a yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
100CrMnSi4-4 +A is rated for continuous service to 200°C (392 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
100CrMnSi4-4 +A conducts electricity at 5.7 % 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 100CrMnSi4-4 +A takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
100CrMnSi4-4 +A's machinability is fair (45/100, worse than 65% of steel grades); weldability not recommended (10/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 100CrMnSi4-4 +A
Is 100CrMnSi4-4 easy to machine?
Machine only in the spheroidise-annealed state (≤207 HB) with rigid setups and coated carbide; hardened 60+ HRC parts require CBN hard turning or grinding.
Can 100CrMnSi4-4 be welded?
Effectively unweldable at ~1 % C — high crack risk; use mechanical joining or shrink fits, and if welding is unavoidable preheat >300 °C and post-anneal immediately.
Can 100CrMnSi4-4 be formed, bent or molded?
Cold heading and cold rolling of ball/roller blanks are practical only after spheroidising; hot forge 1050–1100 °C, finish above 900 °C, then slow-cool and spheroidise anneal.
What surface finishes work on 100CrMnSi4-4?
Grind and superfinish/lap raceways for mirror finish; protect with oil, phosphating, black oxide or thin chrome — no anodising, and avoid electroplating without baking to prevent hydrogen embrittlement.
100CrMnSi4-4 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 through-hardening bearing steel | 0.91 – 1.05 | 0.98 |
| Si | 0.45 – 0.75 | 0.6 |
| Mn | 0.95 – 1.25 | 1.1 |
| Cr | 0.9 – 1.2 | 1.05 |
| Moresidual | ≤ 0.1 | 0.03 |
| Niresidual | ≤ 0.25 | 0.1 |
| Curesidual | ≤ 0.3 | 0.12 |
| P | ≤ 0.03 | 0.01 |
| Slow S for rolling-contact cleanliness | ≤ 0.02 | 0.01 |
| Aldeoxidation residual | ≤ 0.05 | 0.02 |
| Fe | balance | — |
100CrMnSi4-4 +A — frequently asked
What is 100CrMnSi4-4 +A used for?
100CrMnSi4-4 +A is typically used for medium-section bearing rings, cylindrical and tapered rollers, ball bearing inner and outer races, cam follower tracks, linear guide rails and blocks and needle roller pins. In short: deeper hardening than 100Cr6; medium-section bearing grade; not weldable.
What is the yield strength of 100CrMnSi4-4 +A?
100CrMnSi4-4 +A has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 100CrMnSi4-4 +A easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine only in the spheroidise-annealed state (≤207 HB) with rigid setups and coated carbide; hardened 60+ HRC parts require CBN hard turning or grinding.
Can 100CrMnSi4-4 +A be welded?
Not readily — weldability is rated not recommended (10/100). Effectively unweldable at ~1 % C — high crack risk; use mechanical joining or shrink fits, and if welding is unavoidable preheat >300 °C and post-anneal immediately.
What surface finishes work on 100CrMnSi4-4 +A?
Grind and superfinish/lap raceways for mirror finish; protect with oil, phosphating, black oxide or thin chrome — no anodising, and avoid electroplating without baking to prevent hydrogen embrittlement.
Can 100CrMnSi4-4 +A be formed, bent or molded?
Cold heading and cold rolling of ball/roller blanks are practical only after spheroidising; hot forge 1050–1100 °C, finish above 900 °C, then slow-cool and spheroidise anneal.
What is the maximum service temperature of 100CrMnSi4-4 +A?
100CrMnSi4-4 +A 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, alloy steels and free-cutting steels, Part 17: Ball and roller bearing steels — ISO (2014)
- DIN 17230 — Ball and roller bearing steels (superseded, chemistry origin of 1.3518) — DIN (1980)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (bearing steels) — ASM International (1990)
- ASM Handbook Vol. 16 — Machining — ASM International (1989)
- Bearing steel bar programme (100Cr6 / 100CrMnSi6-4 / 100CrMnSi4-4) physical and heat-treatment data — 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.