EN 1.4438 (X2CrNiMo18-15-4) Stainless Steel
EN 1.4438 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the solution annealed (AT) condition. 1.4438 is the EN numeric designation for this material. X2CrNiMo18-15-4 is the EN chemical designation.
It has a moderately low electrical conductivity among wrought austenitic stainless steels. In addition, it has a moderately high base cost and a moderately high embodied energy.
The graph bars on the material properties cards below compare EN 1.4438 stainless steel to: wrought austenitic 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
Brinell Hardness
180
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
41 %
Fatigue Strength
220 MPa 31 x 103 psi
Impact Strength: V-Notched Charpy
90 J 67 ft-lb
Poisson's Ratio
0.28
Shear Modulus
79 GPa 11 x 106 psi
Shear Strength
420 MPa 62 x 103 psi
Tensile Strength: Ultimate (UTS)
620 MPa 90 x 103 psi
Tensile Strength: Yield (Proof)
250 MPa 36 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
420 °C 780 °F
Maximum Temperature: Mechanical
1000 °C 1840 °F
Melting Completion (Liquidus)
1450 °C 2640 °F
Melting Onset (Solidus)
1400 °C 2560 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
14 W/m-K 8.1 BTU/h-ft-°F
Thermal Expansion
16 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.0 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
22 % relative
Density
7.9 g/cm3 500 lb/ft3
Embodied Carbon
4.4 kg CO2/kg material
Embodied Energy
60 MJ/kg 26 x 103 BTU/lb
Embodied Water
160 L/kg 20 gal/lb
Common Calculations
PREN (Pitting Resistance)
31
Resilience: Ultimate (Unit Rupture Work)
200 MJ/m3
Resilience: Unit (Modulus of Resilience)
150 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
22 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
3.7 mm2/s
Thermal Shock Resistance
14 points
Alloy Composition
Among wrought stainless steels, the composition of EN 1.4438 stainless steel is notable for containing comparatively high amounts of nickel (Ni) and chromium (Cr). Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion. Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance.
| Fe | 57.3 to 66.5 | |
| Cr | 17.5 to 19.5 | |
| Ni | 13 to 16 | |
| Mo | 3.0 to 4.0 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 1.0 | |
| N | 0 to 0.1 | |
| P | 0 to 0.045 | |
| C | 0 to 0.030 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10088-2: Stainless steels - Part 2: Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes
EN 10088-3: Stainless steels - Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes
EN 10088-1: Stainless steels - Part 1: List of stainless steels
Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002
Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010