EN 1.5511 (35B2) Boron Steel
EN 1.5511 steel is an alloy steel formulated for primary forming into wrought products. 1.5511 is the EN numeric designation for this material. 35B2 is the EN chemical designation.
It has a very low base cost among EN wrought alloy steels. In addition, it has a fairly low electrical conductivity and a moderately low embodied energy.
The properties of EN 1.5511 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 1.5511 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
150 to 170
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Poisson's Ratio
0.29
Reduction in Area
51 to 69 %
Shear Modulus
72 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
490 to 580 MPa 71 to 83 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
400 °C 750 °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
51 W/m-K 30 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.1 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.1 % IACS
Otherwise Unclassified Properties
Base Metal Price
1.8 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.4 kg CO2/kg material
Embodied Energy
19 MJ/kg 8.0 x 103 BTU/lb
Embodied Water
46 L/kg 5.5 gal/lb
Common Calculations
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
17 to 20 points
Strength to Weight: Bending
18 to 20 points
Thermal Diffusivity
14 mm2/s
Thermal Shock Resistance
15 to 17 points
Alloy Composition
Among alloy steels, the composition of EN 1.5511 steel is notable for including boron (B) and aluminum (Al). Boron is used to improve hardenability. It has a substantial effect when added in even tiny amounts. Aluminum is used to control grain size and to deoxidize. Deoxidizing is required to control the effects of some other alloying elements.
| Fe | 98.3 to 99.159 | |
| Mn | 0.5 to 0.8 | |
| C | 0.32 to 0.39 | |
| Si | 0 to 0.4 | |
| Al | 0.020 to 0.060 | |
| P | 0 to 0.030 | |
| S | 0 to 0.015 | |
| B | 0.00080 to 0.0050 |
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
Boron in Steel, S. K. Banerji and J. E. Morral (editors), 1980
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