EN 1.8866 (P355Q) Steel
EN 1.8866 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the quenched and tempered condition. 1.8866 is the EN numeric designation for this material. P355Q is the EN chemical designation.
It has a moderately high density among EN wrought alloy steels. In addition, it has a moderately high thermal conductivity and a very low tensile strength.
The graph bars on the material properties cards below compare EN 1.8866 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
160
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
25 %
Fatigue Strength
260 MPa 37 x 103 psi
Impact Strength: V-Notched Charpy
67 J 50 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)
540 MPa 78 x 103 psi
Tensile Strength: Yield (Proof)
350 MPa 51 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
410 °C 760 °F
Melting Completion (Liquidus)
1460 °C 2670 °F
Melting Onset (Solidus)
1420 °C 2590 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
48 W/m-K 28 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.3 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.4 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.4 % relative
Density
7.9 g/cm3 490 lb/ft3
Embodied Carbon
1.6 kg CO2/kg material
Embodied Energy
21 MJ/kg 9.1 x 103 BTU/lb
Embodied Water
48 L/kg 5.7 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
120 MJ/m3
Resilience: Unit (Modulus of Resilience)
330 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
19 points
Strength to Weight: Bending
19 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
16 points
Alloy Composition
Among alloy steels, the composition of EN 1.8866 steel is notable for including zirconium (Zr) and boron (B). Zirconium is used to improve ductility. Boron is used to improve hardenability. It has a substantial effect when added in even tiny amounts.
| Fe | 96.3 to 100 | |
| Mn | 0 to 1.5 | |
| Ni | 0 to 0.5 | |
| Si | 0 to 0.4 | |
| Cr | 0 to 0.3 | |
| Cu | 0 to 0.3 | |
| Mo | 0 to 0.25 | |
| C | 0 to 0.16 | |
| V | 0 to 0.060 | |
| Nb | 0 to 0.050 | |
| Zr | 0 to 0.050 | |
| Ti | 0 to 0.030 | |
| P | 0 to 0.025 | |
| N | 0 to 0.015 | |
| S | 0 to 0.010 | |
| B | 0 to 0.0050 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10028-6: Flat products made of steels for pressure purposes - Part 6: Weldable fine grain steels, quenched and tempered
Microstructure of Steels and Cast Irons, Madeleine Durand-Charre, 2004
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