Steel 15CrMo4
EN 15CrMo4
A low-carbon case-hardening chromium-molybdenum steel that develops a hard, wear-resistant carburized surface over a tough, ductile core, commonly used in rolling-element bearing and gear applications.
Reference datasheet — 15CrMo4 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 +A condition
15CrMo4 tempers and conditions
15CrMo4 is supplied in 9 conditions, soft to hard. +A is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Best condition for cold extrusion, cold heading and deep upsetting — softest, most ductile microstructure. | 320 | 500 | 26 | 155 HB | 7.8 % IACS |
Treated for high shearability | Use for cold-shear billet cut-off in forging/cold-heading lines; hardness deliberately capped for clean shear faces. | 340 | 540 | 23 | 160 HB | 7.8 % IACS |
+ADefault Annealed | Standard stock condition for bar and tube: lowest hardness for machining before carburizing. | 350 | 560 | 22 | 170 HB | — |
Supplied with specified hardenability | Order this when case/core depth must be predictable — the heat is certified to a Jominy hardenability band (15CrMo4H). | 360 | 580 | 21 | 40 HRC | 7.8 % IACS |
Treated to ferrite–pearlite structure with specified hardness range | Choose when a uniform ferrite/pearlite microstructure and consistent hardness are needed for stable high-volume machining. | 370 | 590 | 20 | 165 HB | 7.8 % IACS |
Normalized | Grain-refined condition used after hot forging and before carburizing to reduce distortion. | 400 | 620 | 20 | 185 HB | 7.8 % IACS |
Heat treated to a specified hardness range | Pick when incoming bar hardness must sit in a narrow band for automatic machining or cold forming lines. | 420 | 640 | 18 | 13 HRC | 7.8 % IACS |
Cold drawn | Cold-drawn bright bar for close tolerance and good surface directly from stock. | 560 | 700 | 12 | 17 HRC | 7.8 % IACS |
Carburized, direct/re-hardened and low-temperature tempered | The in-service condition: 58–62 HRC wear-resistant case over a tough tempered-martensite core for gears and bearing rings. | 700 | 1,000 | 10 | 60 HRC | — |
What is 15CrMo4?
A low-carbon case-hardening chromium-molybdenum steel that develops a hard, wear-resistant carburized surface over a tough, ductile core, commonly used in rolling-element bearing and gear applications. 15CrMo4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). 15CrMo4 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 74% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
What is 15CrMo4 used for?
- carburized bearing rings
- gears
- camshafts
- pins
- case-hardened shafts
Advantages
- Forms and bends easily — 62/100, better than 78% of steel grades
Limitations
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
15CrMo4 properties
Typical room-temperature values for 15CrMo4-+A; bars are the position among steel grades.
Physical3
15CrMo4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
15CrMo4 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 74% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
15CrMo4 is rated for continuous service to 350°C (662 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
15CrMo4 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 15CrMo4 takes about 31 MJ of energy and emits 2.3 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
15CrMo4's machinability is good (58/100, better than 75% of steel grades); weldability good (65/100); formability good (62/100).
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. 15CrMo4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 15CrMo4
Is 15CrMo4 easy to machine?
Machine fully in the +A/+AC/+TH condition with carbide at ~150–220 m/min; after carburizing only grinding or hard turning with CBN is practical.
Can 15CrMo4 be welded?
Weldable before carburizing with low-hydrogen consumables, 150–250 °C preheat and post-weld stress relief; carburized surfaces should not be welded.
Can 15CrMo4 be formed, bent or molded?
Cold heading and extrusion are done in the spheroidized +AC state; hot forge 1100–850 °C then normalize to refine grain before case hardening.
15CrMo4 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 |
|---|---|---|
| Ccase-hardening carbon level | 0.13 – 0.18 | 0.15 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | |
| Slower max (≤0.015) for bearing-quality | ≤ 0.04 | |
| Cr | 0.8 – 1.15 | 1 |
| Mo | 0.15 – 0.25 | 0.2 |
| Fe | balance |
What surface finishes work on 15CrMo4?
No anodizing — use case hardening plus grinding/honing, and phosphate, black oxide, zinc or nickel plating (with bake-out) for corrosion protection.
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 15CrMo4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.3566
- Similar grades
- 4118
How much does 15CrMo4 cost?
15CrMo4 is a budget-cost steel ($), cheaper than about 90% 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.
15CrMo4 — frequently asked
What is 15CrMo4 used for?
15CrMo4 is typically used for carburized bearing rings, gears, camshafts, pins and case-hardened shafts. In short: bearing-grade case-hardening steel; hard case, tough core; machine soft, harden after.
What is the yield strength of 15CrMo4?
15CrMo4 has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 74% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 15CrMo4 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine fully in the +A/+AC/+TH condition with carbide at ~150–220 m/min; after carburizing only grinding or hard turning with CBN is practical.
Can 15CrMo4 be welded?
Yes — weldability is rated good (65/100). Weldable before carburizing with low-hydrogen consumables, 150–250 °C preheat and post-weld stress relief; carburized surfaces should not be welded.
What surface finishes work on 15CrMo4?
No anodizing — use case hardening plus grinding/honing, and phosphate, black oxide, zinc or nickel plating (with bake-out) for corrosion protection.
Can 15CrMo4 be formed, bent or molded?
Cold heading and extrusion are done in the spheroidized +AC state; hot forge 1100–850 °C then normalize to refine grain before case hardening.
What is the maximum service temperature of 15CrMo4?
15CrMo4 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 15CrMo4 +A and 15CrMo4 CARB?
+A is the default condition — standard stock condition for bar and tube: lowest hardness for machining before carburizing. CARB: the in-service condition: 58–62 HRC wear-resistant case over a tough tempered-martensite core for gears and bearing rings. Yield strength is 350 MPa in +A versus 700 MPa in CARB.
How much does 15CrMo4 cost?
15CrMo4 is a budget-cost steel ($), cheaper than about 90% 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
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- ISO 683-17 — Heat-treatable steels, alloy steels: ball and roller bearing steels — ISO (2014)
- SAE J404 — Chemical compositions of SAE alloy steels (4118) — SAE International (2009)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing of Cr-Mo case-hardening steels) — ASM International (1991)
- Case-hardening steel bar datasheets (Böhler / Ovako / Dörrenberg equivalent grades) — various producers (2023)
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.