MakeItFrom.com
Menu (ESC)

EN 1.7272 (31CrMoB2-1) Boron Steel

EN 1.7272 steel is an alloy steel formulated for primary forming into wrought products. 1.7272 is the EN numeric designation for this material. 31CrMoB2-1 is the EN chemical designation.

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

The properties of EN 1.7272 steel include four common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare EN 1.7272 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

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)

490 to 1650 MPa 71 to 240 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

410 °C 770 °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

45 W/m-K 26 BTU/h-ft-°F

Thermal Expansion

13 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.2 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.3 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.2 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.5 kg CO2/kg material

Embodied Energy

19 MJ/kg 8.3 x 103 BTU/lb

Embodied Water

49 L/kg 5.9 gal/lb

Common Calculations

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

17 to 59 points

Strength to Weight: Bending

18 to 40 points

Thermal Diffusivity

12 mm2/s

Thermal Shock Resistance

14 to 48 points

Alloy Composition

Among alloy steels, the composition of EN 1.7272 steel is notable for containing a comparatively high amount of manganese (Mn) and including boron (B). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however. Boron is used to improve hardenability. It has a substantial effect when added in even tiny amounts.

Iron (Fe) 97.2 to 98.3
Manganese (Mn) 0.9 to 1.2
Chromium (Cr) 0.4 to 0.55
Carbon (C) 0.28 to 0.33
Silicon (Si) 0 to 0.3
Molybdenum (Mo) 0.1 to 0.15
Copper (Cu) 0 to 0.25
Phosphorus (P) 0 to 0.025
Sulfur (S) 0 to 0.025
Boron (B) 0.00080 to 0.0050

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

Followup Questions

Similar Alloys

Further Reading

Boron in Steel, S. K. Banerji and J. E. Morral (editors), 1980

EN 10263-4: Steel rod, bars and wire for cold heading and cold extrusion - Part 4: Technical delivery conditions for steels for quenching and tempering

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