EN 1.6308 (18MnMoNi5-5) Nickel-Molybdenum Steel
EN 1.6308 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the quenched and tempered condition. 1.6308 is the EN numeric designation for this material. 18MnMoNi5-5 is the EN chemical designation.
It has a moderately high density among EN wrought alloy steels. In addition, it has a fairly low thermal conductivity and a moderately low tensile strength.
The graph bars on the material properties cards below compare EN 1.6308 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
180
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
23 %
Fatigue Strength
320 MPa 47 x 103 psi
Impact Strength: V-Notched Charpy
54 J 40 ft-lb
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
390 MPa 56 x 103 psi
Tensile Strength: Ultimate (UTS)
610 MPa 88 x 103 psi
Tensile Strength: Yield (Proof)
460 MPa 66 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
410 °C 770 °F
Melting Completion (Liquidus)
1460 °C 2670 °F
Melting Onset (Solidus)
1420 °C 2590 °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
7.3 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.4 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.8 % relative
Density
7.9 g/cm3 490 lb/ft3
Embodied Carbon
1.6 kg CO2/kg material
Embodied Energy
22 MJ/kg 9.3 x 103 BTU/lb
Embodied Water
50 L/kg 6.0 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
130 MJ/m3
Resilience: Unit (Modulus of Resilience)
550 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
22 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
10 mm2/s
Thermal Shock Resistance
18 points
Alloy Composition
Among alloy steels, the composition of EN 1.6308 steel is notable for containing a comparatively high amount of manganese (Mn). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however.
| Fe | 96.4 to 97.9 | |
| Mn | 1.2 to 1.6 | |
| Ni | 0.5 to 0.8 | |
| Mo | 0.45 to 0.55 | |
| Si | 0 to 0.4 | |
| C | 0 to 0.2 | |
| V | 0 to 0.030 | |
| P | 0 to 0.025 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10222-2: Steel forgings for pressure purposes - Part 2: Ferritic and martensitic steels with specified elevated temperature properties
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