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.
| Fe | 81.8 to 86 | |
| Cr | 14 to 16 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 1.0 | |
| C | 0 to 0.12 | |
| 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 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