Quenched and Tempered (+QT840) 1.4418 Stainless Steel
EN 1.4418 +QT840 steel is EN 1.4418 stainless steel in the quenched and tempered condition. It has the lowest ductility compared to the other variants of EN 1.4418 stainless steel. The graph bars on the material properties cards below compare EN 1.4418 +QT840 steel to: wrought martensitic stainless 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
200 GPa 29 x 106 psi
Elongation at Break
16 %
Fatigue Strength
440 MPa 64 x 103 psi
Impact Strength: V-Notched Charpy
62 J 45 ft-lb
Poisson's Ratio
0.28
Shear Modulus
77 GPa 11 x 106 psi
Shear Strength
590 MPa 86 x 103 psi
Tensile Strength: Ultimate (UTS)
970 MPa 140 x 103 psi
Tensile Strength: Yield (Proof)
750 MPa 110 x 103 psi
Thermal Properties
Latent Heat of Fusion
280 J/g
Maximum Temperature: Corrosion
410 °C 760 °F
Maximum Temperature: Mechanical
870 °C 1600 °F
Melting Completion (Liquidus)
1450 °C 2630 °F
Melting Onset (Solidus)
1400 °C 2550 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.7 BTU/h-ft-°F
Thermal Expansion
10 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.5 % IACS
Otherwise Unclassified Properties
Base Metal Price
13 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
2.8 kg CO2/kg material
Embodied Energy
39 MJ/kg 17 x 103 BTU/lb
Embodied Water
130 L/kg 15 gal/lb
Common Calculations
PREN (Pitting Resistance)
20
Resilience: Ultimate (Unit Rupture Work)
140 MJ/m3
Resilience: Unit (Modulus of Resilience)
1410 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
34 points
Strength to Weight: Bending
28 points
Thermal Diffusivity
4.0 mm2/s
Thermal Shock Resistance
35 points
Alloy Composition
| Fe | 73.2 to 80.2 | |
| Cr | 15 to 17 | |
| Ni | 4.0 to 6.0 | |
| Mo | 0.8 to 1.5 | |
| Mn | 0 to 1.5 | |
| Si | 0 to 0.7 | |
| C | 0 to 0.060 | |
| P | 0 to 0.040 | |
| N | 0 to 0.020 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Further Reading
EN 10250-4: Open die steel forgings for general engineering purposes - Part 4: Stainless steels
EN 10088-2: Stainless steels - Part 2: Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes
EN 10088-1: Stainless steels - Part 1: List of stainless steels
Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012
Corrosion of Stainless Steels, A. John Sedriks, 1996
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010