EN 1.5503 (18B2) Boron Steel
EN 1.5503 steel is an alloy steel formulated for primary forming into wrought products. 1.5503 is the EN numeric designation for this material. 18B2 is the EN chemical designation.
It has a very low base cost among EN wrought alloy steels. In addition, it has a very low electrical conductivity and a very high thermal conductivity.
The properties of EN 1.5503 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 1.5503 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
120 to 160
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
12 to 17 %
Fatigue Strength
180 to 280 MPa 26 to 41 x 103 psi
Poisson's Ratio
0.29
Reduction in Area
63 to 72 %
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
270 to 320 MPa 40 to 47 x 103 psi
Tensile Strength: Ultimate (UTS)
400 to 520 MPa 57 to 76 x 103 psi
Tensile Strength: Yield (Proof)
270 to 430 MPa 40 to 62 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 2590 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
52 W/m-K 30 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.0 % 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
18 MJ/kg 7.9 x 103 BTU/lb
Embodied Water
46 L/kg 5.5 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
41 to 81 MJ/m3
Resilience: Unit (Modulus of Resilience)
200 to 490 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
14 to 19 points
Strength to Weight: Bending
15 to 18 points
Thermal Diffusivity
14 mm2/s
Thermal Shock Resistance
12 to 15 points
Alloy Composition
Among alloy steels, the composition of EN 1.5503 steel is notable for including boron (B). Boron is used to improve hardenability. It has a substantial effect when added in even tiny amounts.
| Fe | 98.4 to 99.239 | |
| Mn | 0.6 to 0.8 | |
| C | 0.16 to 0.2 | |
| Si | 0 to 0.3 | |
| Cu | 0 to 0.25 | |
| P | 0 to 0.025 | |
| S | 0 to 0.025 | |
| 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 10263-3: Steel rod, bars and wire for cold heading and cold extrusion - Part 3: Technical delivery conditions for case hardening steels
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