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AISI 439 (S43035) Stainless Steel

AISI 439 stainless steel is a ferritic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 439 is the AISI designation for this material. S43035 is the UNS number.

The graph bars on the material properties cards below compare AISI 439 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

23 %

Fatigue Strength

170 MPa 25 x 103 psi

Poisson's Ratio

0.28

Reduction in Area

51 %

Rockwell B Hardness

78

Shear Modulus

77 GPa 11 x 106 psi

Shear Strength

310 MPa 45 x 103 psi

Tensile Strength: Ultimate (UTS)

490 MPa 70 x 103 psi

Tensile Strength: Yield (Proof)

250 MPa 36 x 103 psi

Thermal Properties

Latent Heat of Fusion

280 J/g

Maximum Temperature: Corrosion

530 °C 990 °F

Maximum Temperature: Mechanical

890 °C 1640 °F

Melting Completion (Liquidus)

1510 °C 2750 °F

Melting Onset (Solidus)

1430 °C 2600 °F

Specific Heat Capacity

480 J/kg-K 0.12 BTU/lb-°F

Thermal Conductivity

25 W/m-K 14 BTU/h-ft-°F

Thermal Expansion

11 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.9 % IACS

Electrical Conductivity: Equal Weight (Specific)

3.4 % IACS

Otherwise Unclassified Properties

Base Metal Price

9.0 % relative

Calomel Potential

-220 mV

Density

7.7 g/cm3 480 lb/ft3

Embodied Carbon

2.3 kg CO2/kg material

Embodied Energy

34 MJ/kg 14 x 103 BTU/lb

Embodied Water

120 L/kg 15 gal/lb

Common Calculations

PREN (Pitting Resistance)

18

Resilience: Ultimate (Unit Rupture Work)

95 MJ/m3

Resilience: Unit (Modulus of Resilience)

160 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

18 points

Strength to Weight: Bending

18 points

Thermal Diffusivity

6.7 mm2/s

Thermal Shock Resistance

16 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 439 stainless steel is notable for including aluminum (Al) and titanium (Ti). Aluminum is used to improve oxidation resistance. It can also enhance the effects of heat treatment. Titanium is used to broadly improve mechanical properties.

Iron (Fe) 77.1 to 82.8
Chromium (Cr) 17 to 19
Titanium (Ti) 0.2 to 1.1
Manganese (Mn) 0 to 1.0
Silicon (Si) 0 to 1.0
Nickel (Ni) 0 to 0.5
Aluminum (Al) 0 to 0.15
Phosphorus (P) 0 to 0.040
Carbon (C) 0 to 0.030
Sulfur (S) 0 to 0.030
Nitrogen (N) 0 to 0.030

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

Followup Questions

Similar Alloys

Further Reading

ASTM A479: Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

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

Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011

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