MakeItFrom.com
Menu (ESC)

EN 1.7709 (21CrMoV5-7) Steel

EN 1.7709 steel is an alloy steel formulated for primary forming into wrought products. 1.7709 is the EN numeric designation for this material. 21CrMoV5-7 is the EN chemical designation.

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

The properties of EN 1.7709 steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare EN 1.7709 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

200 to 230

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)

650 to 780 MPa 95 to 110 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

440 °C 820 °F

Melting Completion (Liquidus)

1470 °C 2670 °F

Melting Onset (Solidus)

1420 °C 2600 °F

Specific Heat Capacity

470 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

33 W/m-K 19 BTU/h-ft-°F

Thermal Expansion

11 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.5 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.6 % IACS

Otherwise Unclassified Properties

Base Metal Price

3.4 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

2.3 kg CO2/kg material

Embodied Energy

32 MJ/kg 14 x 103 BTU/lb

Embodied Water

56 L/kg 6.7 gal/lb

Common Calculations

PREN (Pitting Resistance)

3.6

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

23 to 27 points

Strength to Weight: Bending

21 to 24 points

Thermal Diffusivity

8.9 mm2/s

Thermal Shock Resistance

22 to 26 points

Alloy Composition

Among alloy steels, the composition of EN 1.7709 steel is notable for including aluminum (Al) and vanadium (V). Aluminum is used to control grain size and to deoxidize. Deoxidizing is required to control the effects of some other alloying elements. Vanadium has a strong hardening effect, but this effect is particularly sensitive to the type of tempering.

Iron (Fe) 95.2 to 97.5
Chromium (Cr) 1.2 to 1.5
Molybdenum (Mo) 0.55 to 0.8
Manganese (Mn) 0.4 to 0.8
Nickel (Ni) 0 to 0.6
Vanadium (V) 0.2 to 0.35
Carbon (C) 0.17 to 0.25
Silicon (Si) 0 to 0.4
Sulfur (S) 0 to 0.030
Aluminum (Al) 0 to 0.030
Phosphorus (P) 0 to 0.025

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

EN 10269: Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties

Creep-Resistant Steels, Fujio Abe et al. (editors), 2008

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