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.
| Fe | 72.1 to 79.3 | |
| Cr | 14 to 16 | |
| Ni | 5.0 to 7.0 | |
| Cu | 1.3 to 1.8 | |
| Mo | 0.5 to 1.0 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 1.0 | |
| C | 0 to 0.050 | |
| P | 0 to 0.040 | |
| 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