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AISI 429 (S42900) Stainless Steel

AISI 429 stainless steel is a ferritic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 429 is the AISI designation for this material. S42900 is the UNS number.

It has a moderately low embodied energy among wrought ferritic stainless steels. In addition, it has a moderately high ductility and a moderately high thermal conductivity.

The graph bars on the material properties cards below compare AISI 429 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 28 x 106 psi

Elongation at Break

25 %

Fatigue Strength

180 MPa 26 x 103 psi

Poisson's Ratio

0.28

Reduction in Area

50 %

Rockwell B Hardness

78

Shear Modulus

77 GPa 11 x 106 psi

Shear Strength

300 MPa 44 x 103 psi

Tensile Strength: Ultimate (UTS)

480 MPa 69 x 103 psi

Tensile Strength: Yield (Proof)

260 MPa 38 x 103 psi

Thermal Properties

Latent Heat of Fusion

280 J/g

Maximum Temperature: Corrosion

400 °C 750 °F

Maximum Temperature: Mechanical

810 °C 1490 °F

Melting Completion (Liquidus)

1440 °C 2630 °F

Melting Onset (Solidus)

1400 °C 2550 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

26 W/m-K 15 BTU/h-ft-°F

Thermal Expansion

10 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

7.5 % relative

Density

7.7 g/cm3 480 lb/ft3

Embodied Carbon

2.0 kg CO2/kg material

Embodied Energy

28 MJ/kg 12 x 103 BTU/lb

Embodied Water

110 L/kg 13 gal/lb

Common Calculations

PREN (Pitting Resistance)

15

Resilience: Ultimate (Unit Rupture Work)

99 MJ/m3

Resilience: Unit (Modulus of Resilience)

170 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

6.9 mm2/s

Thermal Shock Resistance

17 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 429 stainless steel is notable for containing comparatively high amounts of chromium (Cr) and manganese (Mn). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Manganese is used to improve ductility at elevated temperatures. It also permits a higher nitrogen content than would otherwise be possible.

Iron (Fe) 81.8 to 86
Chromium (Cr) 14 to 16
Manganese (Mn) 0 to 1.0
Silicon (Si) 0 to 1.0
Carbon (C) 0 to 0.12
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 A493: Standard Specification for Stainless Steel Wire and Wire Rods for Cold Heading and Cold Forging

ASTM A473: Standard Specification for Stainless Steel Forgings

ASTM A182: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service

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