EN 1.6781 (G17NiCrMo13-6) Cast Steel
EN 1.6781 steel is an alloy steel formulated for casting. Cited properties are appropriate for the quenched and tempered condition. 1.6781 is the EN numeric designation for this material. G17NiCrMo13-6 is the EN chemical designation.
It has a fairly high base cost among cast alloy steels. In addition, it has a moderately high electrical conductivity and a moderately low ductility.
The graph bars on the material properties cards below compare EN 1.6781 steel to: cast 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
250
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
17 %
Fatigue Strength
450 MPa 65 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
830 MPa 120 x 103 psi
Tensile Strength: Yield (Proof)
680 MPa 98 x 103 psi
Thermal Properties
Latent Heat of Fusion
260 J/g
Maximum Temperature: Mechanical
450 °C 840 °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 26 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.9 % IACS
Electrical Conductivity: Equal Weight (Specific)
9.1 % IACS
Otherwise Unclassified Properties
Base Metal Price
5.0 % relative
Density
7.9 g/cm3 490 lb/ft3
Embodied Carbon
1.9 kg CO2/kg material
Embodied Energy
25 MJ/kg 11 x 103 BTU/lb
Embodied Water
60 L/kg 7.2 gal/lb
Common Calculations
PREN (Pitting Resistance)
3.3
Resilience: Ultimate (Unit Rupture Work)
130 MJ/m3
Resilience: Unit (Modulus of Resilience)
1220 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
29 points
Strength to Weight: Bending
25 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
24 points
Alloy Composition
Among cast alloy steels, the composition of EN 1.6781 steel is notable for containing comparatively high amounts of nickel (Ni) and chromium (Cr). Nickel is used to improve mechanical properties, and to make the alloy easier to heat treat. Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures).
| Fe | 92.6 to 94.6 | |
| Ni | 3.0 to 3.5 | |
| Cr | 1.3 to 1.8 | |
| Mn | 0.55 to 0.8 | |
| Mo | 0.45 to 0.6 | |
| Si | 0 to 0.5 | |
| C | 0.15 to 0.19 | |
| P | 0 to 0.015 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ISO 4991: Steel castings for pressure purposes
EN 10293: Steel castings - Steel castings for general engineering uses
ASM Specialty Handbook: Carbon and Alloy Steels, J. R. Davis (editor), 1996
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