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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.

Iron (Fe) 57.3 to 66.5
Chromium (Cr) 17.5 to 19.5
Nickel (Ni) 13 to 16
Molybdenum (Mo) 3.0 to 4.0
Manganese (Mn) 0 to 2.0
Silicon (Si) 0 to 1.0
Nitrogen (N) 0 to 0.1
Phosphorus (P) 0 to 0.045
Carbon (C) 0 to 0.030
Sulfur (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