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EN 1.7707 (30CrMoV9) Chromium Steel

EN 1.7707 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the quenched and tempered condition. 1.7707 is the EN numeric designation for this material. 30CrMoV9 is the EN chemical designation.

It has a fairly low thermal conductivity among EN wrought alloy steels. In addition, it has a fairly high embodied energy and a moderately high electrical conductivity.

The graph bars on the material properties cards below compare EN 1.7707 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

300

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

11 %

Fatigue Strength

500 MPa 72 x 103 psi

Impact Strength: V-Notched Charpy

31 J 23 ft-lb

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

600 MPa 88 x 103 psi

Tensile Strength: Ultimate (UTS)

1010 MPa 150 x 103 psi

Tensile Strength: Yield (Proof)

800 MPa 120 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

460 °C 850 °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

39 W/m-K 23 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

3.3 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.9 kg CO2/kg material

Embodied Energy

27 MJ/kg 11 x 103 BTU/lb

Embodied Water

58 L/kg 7.0 gal/lb

Common Calculations

PREN (Pitting Resistance)

3.2

Resilience: Ultimate (Unit Rupture Work)

110 MJ/m3

Resilience: Unit (Modulus of Resilience)

1690 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

36 points

Strength to Weight: Bending

29 points

Thermal Diffusivity

11 mm2/s

Thermal Shock Resistance

29 points

Alloy Composition

Among alloy steels, the composition of EN 1.7707 steel is notable for containing a comparatively high amount of chromium (Cr) and including vanadium (V). Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures). Vanadium has a strong hardening effect, but this effect is particularly sensitive to the type of tempering.

Iron (Fe)Fe 94.7 to 96.8
Chromium (Cr)Cr 2.3 to 2.7
Manganese (Mn)Mn 0.4 to 0.7
Carbon (C)C 0.26 to 0.34
Nickel (Ni)Ni 0 to 0.6
Silicon (Si)Si 0 to 0.4
Molybdenum (Mo)Mo 0.15 to 0.25
Vanadium (V)V 0.1 to 0.2
Phosphorus (P)P 0 to 0.035
Sulfur (S)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

Microstructure of Steels and Cast Irons, Madeleine Durand-Charre, 2004

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