EN 1.7378 (7CrMoVTiB10-10) Chromium-Molybdenum Steel
EN 1.7378 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the normalized and tempered condition. 1.7378 is the EN numeric designation for this material. 7CrMoVTiB10-10 is the EN chemical designation.
It has a very high melting temperature among EN wrought alloy steels. In addition, it has a fairly low thermal conductivity and a very high embodied energy.
The graph bars on the material properties cards below compare EN 1.7378 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
210
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
17 %
Fatigue Strength
330 MPa 47 x 103 psi
Impact Strength: V-Notched Charpy
38 J 28 ft-lb
Poisson's Ratio
0.29
Shear Modulus
74 GPa 11 x 106 psi
Shear Strength
430 MPa 63 x 103 psi
Tensile Strength: Ultimate (UTS)
700 MPa 100 x 103 psi
Tensile Strength: Yield (Proof)
490 MPa 71 x 103 psi
Thermal Properties
Latent Heat of Fusion
260 J/g
Maximum Temperature: Mechanical
460 °C 860 °F
Melting Completion (Liquidus)
1470 °C 2680 °F
Melting Onset (Solidus)
1430 °C 2600 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
39 W/m-K 22 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.6 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.7 % IACS
Otherwise Unclassified Properties
Base Metal Price
4.0 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
2.3 kg CO2/kg material
Embodied Energy
33 MJ/kg 14 x 103 BTU/lb
Embodied Water
61 L/kg 7.2 gal/lb
Common Calculations
PREN (Pitting Resistance)
5.8
Resilience: Ultimate (Unit Rupture Work)
110 MJ/m3
Resilience: Unit (Modulus of Resilience)
630 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
25 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
10 mm2/s
Thermal Shock Resistance
20 points
Alloy Composition
Among alloy steels, the composition of EN 1.7378 steel is notable for including boron (B) and titanium (Ti). Boron is used to improve hardenability. It has a substantial effect when added in even tiny amounts. Titanium is used to broadly improve mechanical properties.
| Fe | 94.6 to 96.1 | |
| Cr | 2.2 to 2.6 | |
| Mo | 0.9 to 1.1 | |
| Mn | 0.3 to 0.7 | |
| Si | 0.15 to 0.45 | |
| V | 0.2 to 0.3 | |
| C | 0.050 to 0.1 | |
| Ti | 0.050 to 0.1 | |
| P | 0 to 0.020 | |
| Al | 0 to 0.020 | |
| S | 0 to 0.010 | |
| N | 0 to 0.010 | |
| B | 0.0015 to 0.0070 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10216-2: Seamless steel tubes for pressure purposes - Technical delivery conditions - Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015