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EN 1.7027 (20Cr4) Case-Hardening Bearing Steel

EN 1.7027 steel is an alloy steel formulated for primary forming into wrought products. 1.7027 is the EN numeric designation for this material. 20Cr4 is the EN chemical designation. It has a moderately low embodied energy and a moderately low electrical conductivity among EN wrought alloy steels.

The properties of EN 1.7027 steel include five 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 1.7027 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 180

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 1460 MPa 70 to 210 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

420 °C 790 °F

Melting Completion (Liquidus)

1460 °C 2660 °F

Melting Onset (Solidus)

1420 °C 2580 °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

7.2 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.3 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.3 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.4 kg CO2/kg material

Embodied Energy

19 MJ/kg 8.2 x 103 BTU/lb

Embodied Water

51 L/kg 6.1 gal/lb

Common Calculations

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

17 to 52 points

Strength to Weight: Bending

18 to 36 points

Thermal Diffusivity

12 mm2/s

Thermal Shock Resistance

14 to 43 points

Alloy Composition

Among alloy steels, the composition of EN 1.7027 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.

Iron (Fe)Fe 97.1 to 98.5
Chromium (Cr)Cr 0.9 to 1.2
Manganese (Mn)Mn 0.6 to 0.9
Carbon (C)C 0.17 to 0.23
Silicon (Si)Si 0 to 0.4
Copper (Cu)Cu 0 to 0.3
Aluminum (Al)Al 0 to 0.050
Sulfur (S)S 0 to 0.030
Phosphorus (P)P 0 to 0.025
Oxygen (O)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

Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008

Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015