EN 1.8959 (S355J0W) Weathering Steel
EN 1.8959 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the hot worked condition. 1.8959 is the EN numeric designation for this material. S355J0W is the EN chemical designation.
It has a fairly low thermal conductivity among EN wrought alloy steels. In addition, it has a moderately high electrical conductivity and a fairly low tensile strength.
The graph bars on the material properties cards below compare EN 1.8959 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
170
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
16 %
Fatigue Strength
220 MPa 32 x 103 psi
Impact Strength: V-Notched Charpy
30 J 22 ft-lb
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
350 MPa 50 x 103 psi
Tensile Strength: Ultimate (UTS)
570 MPa 82 x 103 psi
Tensile Strength: Yield (Proof)
340 MPa 49 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
420 °C 780 °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
39 W/m-K 22 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
2.7 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.6 kg CO2/kg material
Embodied Energy
21 MJ/kg 9.2 x 103 BTU/lb
Embodied Water
52 L/kg 6.2 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
78 MJ/m3
Resilience: Unit (Modulus of Resilience)
300 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
20 points
Strength to Weight: Bending
19 points
Thermal Diffusivity
10 mm2/s
Thermal Shock Resistance
17 points
Alloy Composition
Among alloy steels, the composition of EN 1.8959 steel is notable for including zirconium (Zr) and containing a comparatively high amount of manganese (Mn). Zirconium is used to improve ductility. Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however.
| Fe | 94.9 to 99 | |
| Mn | 0.45 to 1.6 | |
| Cr | 0.35 to 0.85 | |
| Cu | 0.2 to 0.6 | |
| Ni | 0 to 0.7 | |
| Si | 0 to 0.55 | |
| Mo | 0 to 0.35 | |
| C | 0 to 0.19 | |
| Zr | 0 to 0.17 | |
| P | 0 to 0.040 | |
| S | 0 to 0.040 | |
| N | 0 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10025-5: Hot rolled products of structural steels - Part 5: Technical delivery conditions for structural steels with improved atmospheric corrosion resistance
Real Material Properties of Weathering Steels Used in Bridge Structures, Vit Krivy and Petr Konecny, 2013
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015