EN 1.3566 (15CrMo4) Case-Hardening Bearing Steel
EN 1.3566 steel is an alloy steel formulated for primary forming into wrought products. 1.3566 is the EN numeric designation for this material. 15CrMo4 is the EN chemical designation.
The properties of EN 1.3566 steel include six common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare EN 1.3566 steel to: EN wrought alloy steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Brinell Hardness
150 to 220
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
490 to 1380 MPa 70 to 200 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
420 °C 800 °F
Melting Completion (Liquidus)
1460 °C 2660 °F
Melting Onset (Solidus)
1420 °C 2590 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
45 W/m-K 26 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.3 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.5 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.5 kg CO2/kg material
Embodied Energy
20 MJ/kg 8.5 x 103 BTU/lb
Embodied Water
52 L/kg 6.2 gal/lb
Common Calculations
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
17 to 49 points
Strength to Weight: Bending
17 to 35 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
14 to 40 points
Alloy Composition
Among alloy steels, the composition of EN 1.3566 steel is notable for including aluminum (Al) and copper (Cu). Aluminum is used to control grain size and to deoxidize. Deoxidizing is required to control the effects of some other alloying elements. Copper is used to improve corrosion resistance, and to add at least some degree of precipitation hardenability.
| Fe | 96.8 to 98.4 | |
| Cr | 0.9 to 1.2 | |
| Mn | 0.6 to 0.9 | |
| Si | 0 to 0.4 | |
| Mo | 0.15 to 0.25 | |
| C | 0.12 to 0.18 | |
| Cu | 0 to 0.3 | |
| Al | 0 to 0.050 | |
| S | 0 to 0.030 | |
| P | 0 to 0.025 | |
| O | 0 to 0.0020 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ISO 683-17: Heat-treated steels, alloy steels and free-cutting steels - Part 17: Ball and roller bearing steels
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015