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AISI 445 (S44500) Stainless Steel

AISI 445 stainless steel is a ferritic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 445 is the AISI designation for this material. S44500 is the UNS number.

It has a moderately high ductility among the wrought ferritic stainless steels in the database.

The graph bars on the material properties cards below compare AISI 445 stainless steel to: wrought ferritic 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

160

Elastic (Young's, Tensile) Modulus

200 GPa 29 x 106 psi

Elongation at Break

25 %

Fatigue Strength

160 MPa 23 x 103 psi

Poisson's Ratio

0.28

Rockwell B Hardness

71

Shear Modulus

78 GPa 11 x 106 psi

Shear Strength

310 MPa 44 x 103 psi

Tensile Strength: Ultimate (UTS)

480 MPa 69 x 103 psi

Tensile Strength: Yield (Proof)

230 MPa 34 x 103 psi

Thermal Properties

Latent Heat of Fusion

290 J/g

Maximum Temperature: Corrosion

480 °C 890 °F

Maximum Temperature: Mechanical

950 °C 1740 °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

21 W/m-K 12 BTU/h-ft-°F

Thermal Expansion

11 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.6 % IACS

Electrical Conductivity: Equal Weight (Specific)

3.0 % IACS

Otherwise Unclassified Properties

Base Metal Price

12 % relative

Density

7.7 g/cm3 480 lb/ft3

Embodied Carbon

2.6 kg CO2/kg material

Embodied Energy

38 MJ/kg 16 x 103 BTU/lb

Embodied Water

130 L/kg 16 gal/lb

Common Calculations

PREN (Pitting Resistance)

20

Resilience: Ultimate (Unit Rupture Work)

98 MJ/m3

Resilience: Unit (Modulus of Resilience)

140 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

17 points

Strength to Weight: Bending

18 points

Thermal Diffusivity

5.6 mm2/s

Thermal Shock Resistance

16 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 445 stainless steel is notable for including niobium (Nb) and copper (Cu). Niobium is primarily used to improve yield strength, particularly at elevated temperatures. Copper is used to improve resistance to acids, and to improve formability.

Iron (Fe) 74.9 to 80.7
Chromium (Cr) 19 to 21
Manganese (Mn) 0 to 1.0
Silicon (Si) 0 to 1.0
Copper (Cu) 0.3 to 0.6
Niobium (Nb) 0 to 0.8
Nickel (Ni) 0 to 0.6
Phosphorus (P) 0 to 0.040
Nitrogen (N) 0 to 0.030
Carbon (C) 0 to 0.020
Sulfur (S) 0 to 0.012

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

Followup Questions

Similar Alloys

Further Reading

ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications

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

Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012

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

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015