EN 1.7243 (18CrMo4) Chromium-Molybdenum Steel
EN 1.7243 steel is an alloy steel formulated for primary forming into wrought products. 1.7243 is the EN numeric designation for this material. 18CrMo4 is the EN chemical designation.
The properties of EN 1.7243 steel include four 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 1.7243 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 170
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)
480 to 1390 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
44 W/m-K 25 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
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 49 points
Strength to Weight: Bending
17 to 35 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
14 to 41 points
Alloy Composition
Among alloy steels, the composition of EN 1.7243 steel is notable for including copper (Cu) and containing a comparatively high amount of chromium (Cr). Copper is used to improve corrosion resistance, and to add at least some degree of precipitation hardenability. Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures).
| Fe | 96.8 to 98.2 | |
| Cr | 0.9 to 1.2 | |
| Mn | 0.6 to 0.9 | |
| Si | 0 to 0.4 | |
| Mo | 0.15 to 0.25 | |
| C | 0.15 to 0.21 | |
| Cu | 0 to 0.25 | |
| P | 0 to 0.035 | |
| S | 0 to 0.035 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10250-3: Open die steel forgings for general engineering purposes - Part 3: Alloy special steels
EN 10263-3: Steel rod, bars and wire for cold heading and cold extrusion - Part 3: Technical delivery conditions for case hardening steels
Welding Metallurgy, 2nd ed., Sindo Kou, 2003
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