Steel 100CrMo7-4
EN 100CrMo7-4
100CrMo7-4 (1.3538) is a through-hardening Cr-Mo bearing steel of the same ~1 %C family as 100CrMo7, with a raised Mo content for deeper hardenability in heavy sections.
Reference datasheet — 100CrMo7-4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +AC condition
100CrMo7-4 tempers and conditions
100CrMo7-4 is supplied in 7 conditions, soft to hard. +AC 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 |
|---|---|---|---|---|---|---|
+ACDefault Spheroidize annealed | Standard stock condition for bearing-ring blanks: soft, globular carbide structure giving the best machinability and cold-forming behaviour before hardening. | 410 | 680 | 20 | 207 HB | 44 W/m·K |
Annealed | General soft-annealed delivery condition when a full spheroidized carbide structure is not contractually required. | 420 | 700 | 18 | 17 HRC | 6.6 % IACS |
Hot rolled | Mill-supplied as-rolled bar for re-heating/forging; hardness too high and structure too banded for direct machining. | 560 | 950 | 10 | 30 HRC | 6.4 % IACS |
Spheroidize annealed and cold drawn bar | Choose for close-tolerance bright bar (rollers, pins, small rings) where the drawn surface and size accuracy save a turning operation. | 620 | 780 | 11 | 235 HB | — |
Bainite hardened | Austempered lower-bainite condition for heavy-section, shock- or contamination-loaded bearings: compressive surface stresses, better toughness and crack resistance than martensite. | 1,650 | 2,000 | 1.5 | 60 HRC | — |
+QT 58–61 HRC | Higher-temper condition for rings that must stay dimensionally stable at elevated running temperature (up to ~180 °C) at slight hardness cost. | 1,750 | 2,050 | 1 | 60 HRC | 36 W/m·K |
+QT 61–64 HRC | Standard finished-bearing condition: maximum hardness and rolling-contact fatigue life for raceways and rolling elements up to ~150 °C. | 1,950 | 2,250 | 0.7 | 62 HRC | 34 W/m·K |
What is 100CrMo7-4?
100CrMo7-4 (1.3538) is a through-hardening Cr-Mo bearing steel of the same ~1 %C family as 100CrMo7, with a raised Mo content for deeper hardenability in heavy sections. It is used for large-diameter and slewing bearing races, supplied as forged rings, tube and bar in spheroidize-annealed condition near 207 HB (680 MPa tensile, 410 MPa yield, 20 % elongation, 44 W/m·K), then hardened to +QT58/+QT62 or bainite-hardened (+B). It is not weldable, has no inherent corrosion resistance, and the listed maximum service temperature is 400 °C. 100CrMo7 covers lighter sections. 100CrMo7-4 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F). 100CrMo7-4 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 57% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
What is 100CrMo7-4 used for?
- Large-diameter rolling bearings
- Slewing ring bearings
- Heavy industrial bearing races
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Difficult to weld — 12/100, worse than 96% of steel grades
- Low electrical conductivity — 6.5 % IACS, worse than 77% of steel grades
100CrMo7-4 properties
Typical room-temperature values for 100CrMo7-4-+AC; bars are the position among steel grades.
Physical3
100CrMo7-4 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
100CrMo7-4 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 57% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
100CrMo7-4 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
100CrMo7-4 conducts electricity at 6.5 % IACS, worse than 77% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 100CrMo7-4 takes about 33 MJ of energy and emits 2.3 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 25%.
Manufacturability8
100CrMo7-4's machinability is fair (45/100, worse than 65% of steel grades); weldability not recommended (12/100); formability fair (45/100).
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. 100CrMo7-4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 100CrMo7-4
Is 100CrMo7-4 easy to machine?
Machine only in the spheroidized (+AC) state with coated carbide at moderate speed; after hardening use CBN hard turning or grinding.
Can 100CrMo7-4 be welded?
Effectively non-weldable at ~1 %C — any fusion welding cracks; use shrink fits, bolting or friction welding with full post-weld heat treatment on non-critical joints.
Can 100CrMo7-4 be formed, bent or molded?
Cold ring rolling / cold heading possible only in fully spheroidized bar; hot forge 1050–1100 °C and cool slowly to avoid network carbides and flakes.
100CrMo7-4 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 |
|---|---|---|
| C | 0.92 – 1.05 | 0.98 |
| Si | 0.2 – 0.4 | 0.3 |
| Mn | 0.6 – 0.8 | 0.7 |
| Cr | 1.65 – 1.95 | 1.8 |
| MoMo addition gives deep hardenability in heavy sections | 0.4 – 0.6 | 0.5 |
| P | ≤ 0.03 | |
| S | ≤ 0.02 | |
| Niresidual, max | ≤ 0.25 | |
| Curesidual, max | ≤ 0.3 | |
| Alresidual, max | ≤ 0.05 | |
| O≤15 ppm total oxygen for bearing quality | ≤ 0 | |
| Fe | balance |
What surface finishes work on 100CrMo7-4?
Hardened raceways are ground and superfinished to Ra <0.05 µm; protect with preservative oil, phosphate, black oxide or thin dense chrome — no anodizing.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 100CrMo7-4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.3538
How much does 100CrMo7-4 cost?
100CrMo7-4 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.
100CrMo7-4 — frequently asked
What is 100CrMo7-4 used for?
100CrMo7-4 is typically used for large-diameter rolling bearings, slewing ring bearings and heavy industrial bearing races. In short: heavy-section bearing steel; deep through-hardenability; bainite-hardened option available.
What is the yield strength of 100CrMo7-4?
100CrMo7-4 has a typical yield strength of 410 MPa (59.5 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 57% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 100CrMo7-4 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine only in the spheroidized (+AC) state with coated carbide at moderate speed; after hardening use CBN hard turning or grinding.
Can 100CrMo7-4 be welded?
Not readily — weldability is rated not recommended (12/100). Effectively non-weldable at ~1 %C — any fusion welding cracks; use shrink fits, bolting or friction welding with full post-weld heat treatment on non-critical joints.
What surface finishes work on 100CrMo7-4?
Hardened raceways are ground and superfinished to Ra <0.05 µm; protect with preservative oil, phosphate, black oxide or thin dense chrome — no anodizing.
Can 100CrMo7-4 be formed, bent or molded?
Cold ring rolling / cold heading possible only in fully spheroidized bar; hot forge 1050–1100 °C and cool slowly to avoid network carbides and flakes.
What is the maximum service temperature of 100CrMo7-4?
100CrMo7-4 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.
What is the difference between 100CrMo7-4 +AC and 100CrMo7-4-HR?
+AC is the default condition — standard stock condition for bearing-ring blanks: soft, globular carbide structure giving the best machinability and cold-forming behaviour before hardening. HR: mill-supplied as-rolled bar for re-heating/forging; hardness too high and structure too banded for direct machining. Yield strength is 410 MPa in +AC versus 560 MPa in HR.
How much does 100CrMo7-4 cost?
100CrMo7-4 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.
Sources
- ISO 683-17 Heat-treatable steels, alloy steels and free-cutting steels — Part 17: Ball and roller bearing steels — ISO (2014)
- EN 10027-2 Designation systems for steels — Steel numbers (1.3538) — CEN (2015)
- ASM Handbook Vol. 1: Properties and Selection — Bearing Steels — ASM International (1990)
- Bearing steel bar datasheets (100Cr6 / 100CrMo7 / 100CrMo7-4 family) — Ovako / Sandvik / Böhler (2023)
- Machinery's Handbook — machinability ratings for high-carbon chromium steels — Industrial Press (2020)
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.