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UNS S45000 (Alloy 450, XM-25) Stainless Steel

S45000 stainless steel is a precipitation-hardening stainless steel formulated for primary forming into wrought products. XM-25 is the ASTM designation for this material. S45000 is the UNS number. And Alloy 450 is the common industry name.

It has a moderately low embodied energy among the wrought precipitation-hardening stainless steels in the database.

The properties of S45000 stainless steel include eight common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare S45000 stainless steel to: wrought precipitation-hardening 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

280 to 410

Elastic (Young's, Tensile) Modulus

200 GPa 28 x 106 psi

Elongation at Break

6.8 to 14 %

Fatigue Strength

330 to 650 MPa 48 to 95 x 103 psi

Poisson's Ratio

0.28

Reduction in Area

22 to 50 %

Rockwell C Hardness

28 to 44

Shear Modulus

76 GPa 11 x 106 psi

Shear Strength

590 to 830 MPa 85 to 120 x 103 psi

Tensile Strength: Ultimate (UTS)

980 to 1410 MPa 140 to 210 x 103 psi

Tensile Strength: Yield (Proof)

580 to 1310 MPa 84 to 190 x 103 psi

Thermal Properties

Latent Heat of Fusion

280 J/g

Maximum Temperature: Corrosion

400 °C 750 °F

Maximum Temperature: Mechanical

840 °C 1550 °F

Melting Completion (Liquidus)

1440 °C 2620 °F

Melting Onset (Solidus)

1390 °C 2540 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

17 W/m-K 9.6 BTU/h-ft-°F

Thermal Expansion

11 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)

17

Resilience: Ultimate (Unit Rupture Work)

94 to 160 MJ/m3

Resilience: Unit (Modulus of Resilience)

850 to 4400 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

35 to 50 points

Strength to Weight: Bending

28 to 36 points

Thermal Diffusivity

4.5 mm2/s

Thermal Shock Resistance

33 to 47 points

Alloy Composition

Among wrought stainless steels, the composition of S45000 stainless steel is notable for including copper (Cu). Copper is used to improve resistance to acids, and to improve formability.

Iron (Fe) 72.1 to 79.3
Chromium (Cr) 14 to 16
Nickel (Ni) 5.0 to 7.0
Copper (Cu) 1.3 to 1.8
Molybdenum (Mo) 0.5 to 1.0
Manganese (Mn) 0 to 1.0
Silicon (Si) 0 to 1.0
Carbon (C) 0 to 0.050
Phosphorus (P) 0 to 0.040
Sulfur (S) 0 to 0.030

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM A564: Standard Specification for Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes

Welding Metallurgy and Weldability of Stainless Steels, John C. Lippold and Damian J. Kotecki, 2005

ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels

Corrosion of Stainless Steels, A. John Sedriks, 1996

ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994

Advances in Stainless Steels, Baldev Raj et al. (editors), 2010