429 (S42900) Ferritic Stainless Steel Plate/Coil
429 (S42900) Ferritic Stainless Steel Plate/Coil: Composition, Properties & Global Equivalents
Detailed material data for 429 (UNS S42900) ferritic stainless steel, covering chemical composition, mechanical and thermal properties, international equivalents, and application guidance for automotive, appliance, and architectural uses.
Hot rolling, cold rolling, annealing, pickling, skin pass
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429 Ferritic Stainless Steel Plate/Coil Introduction
429 (UNS S42900) is a ferritic stainless steel supplied primarily in plate and coil form under ASTM A240/A240M. It contains 14.0–16.0% chromium, providing moderate corrosion resistance in mildly aggressive environments. This grade is non-hardenable by heat treatment and exhibits ferromagnetic behavior.
The alloy is often chosen as a cost-effective alternative to higher-chromium ferritics such as 430, offering a good balance of formability, weldability, and oxidation resistance. It is easily deep-drawn, bent, and stamped, making it well-suited for automotive trim, appliance panels, and architectural cladding. Welding can be performed by most conventional methods, though post-weld annealing is recommended to restore optimal ductility and corrosion resistance.
Due to its fully ferritic microstructure, 429 is immune to chloride-induced stress corrosion cracking, a significant advantage over austenitic stainless steels. It demonstrates good scaling resistance in intermittent service up to approximately 800°C. Mechanical properties in annealed condition include a minimum tensile strength of 450 MPa, yield strength of 205 MPa, and elongation around 22%. Thermal conductivity is higher than that of austenitic grades, while thermal expansion is lower, making it suitable for applications involving thermal cycling.
The combination of moderate corrosion resistance, ease of fabrication, and cost efficiency makes 429 a versatile material for both industrial and consumer products. It is widely available as cold-rolled and hot-rolled sheets and plates in various thicknesses.
429 Ferritic Stainless Steel Plate/Coil Chemical Composition
The chemical composition complies with ASTM A240/A240M for UNS S42900. Low carbon and balanced chromium ensure a stable ferritic microstructure and adequate corrosion resistance. Residual nickel is limited to avoid partial transformation.
| Element | Standard Value | Remark |
|---|---|---|
| Carbon (C) | ≤ 0.12 | |
| Manganese (Mn) | ≤ 1.00 | |
| Phosphorus (P) | ≤ 0.040 | |
| Sulfur (S) | ≤ 0.030 | |
| Silicon (Si) | ≤ 1.00 | |
| Chromium (Cr) | 14.0 - 16.0 | |
| Nickel (Ni) | ≤ 0.75 | Residual; not added intentionally |
429 Ferritic Stainless Steel Plate/Coil Thermal and Electrical Physical Properties
Representative values for fully ferritic stainless steel with ~15% Cr at room temperature unless noted. Thermal conductivity and expansion are beneficial for applications involving heat transfer or dimensional stability under temperature changes.Note: These are typical literature values, not specific ASTM requirements.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.70 | g/cm³ | At 20°C |
| Elastic Modulus (E) | 200 | GPa | At 20°C |
| Shear Modulus (G) | 77 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.28 | - | Estimated |
| Thermal Expansion Coeff. (α) | 10.4 | 10⁻⁶/K | 20–100°C |
| Thermal Expansion Coeff. (α) | 11.4 | 10⁻⁶/K | 20–500°C |
| Thermal Conductivity (λ) | 26 | W/(m·K) | At 100°C |
| Specific Heat Capacity (cₚ) | 460 | J/(kg·K) | At 20°C |
| Electrical Resistivity (ρₑ) | 0.60 | µΩ·m | At 20°C |
429 Ferritic Stainless Steel Plate/Coil Mechanical Properties
Properties represent minimum or maximum limits as specified in ASTM A240 for annealed condition. Actual values may exceed minimums. The alloy exhibits moderate strength and good ductility, suitable for cold forming operations.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength (Rm) | ≥ 450 | MPa | Annealed, room temperature |
| Yield Strength (ReH, 0.2% offset) | ≥ 205 | MPa | Annealed |
| Elongation (A) | ≥ 22 | % | Gauge length 50 mm, thickness ≤ 5.0 mm |
| Hardness | ≤ 88 | HRB | Annealed |
| Bend Test (180°) | D = T (thickness) | Thickness ≤ 5.0 mm, no cracking |
429 Ferritic Stainless Steel Plate/Coil Identical / Fully Equivalent Material Standards and Substitute Grades
| Country/Region | Standard | Grade | Remark |
|---|---|---|---|
| USA | ASTM A240 | 429 (UNS S42900) | Original grade |
| China | GB/T 20878, GB/T 4237 | 10Cr15 (former 1Cr15) | Same chemical composition limits |
| Japan | JIS G 4304 | SUS 429 | Identical Cr, C, and other elements |
429 Ferritic Stainless Steel Plate/Coil Application Introduction
429 stainless steel is employed where good corrosion resistance in mild environments, ease of forming, and cost are critical. Its magnetic ferritic nature makes it suitable for applications requiring magnetic response. While not as corrosion-resistant as higher-Cr 430, it is often selected for non-critical components to save cost.
Product Applications: Automotive trim, moldings, and grills, Exhaust system components (non-structural), Washing machine drums and inner panels, Architectural wall panels and elevator interiors, Cooking utensils and cutlery (low-cost range), Heat exchanger tubes (moderate temperature)
Processed into products: Stamped brackets and clips, Deep-drawn sink bowls, Welded frames and supports, Roll-formed profiles, Laser-cut decorative parts, Hinges and fasteners
Application industries: Automotive, Home appliances, Architecture & construction, Food processing equipment (non-critical), General engineering
429 Ferritic Stainless Steel Plate/Coil Similar / Alternative Stainless Steel Grades with Comparable Properties
| Country/Region | Standard | Grade | Remark |
|---|---|---|---|
| USA | ASTM A240 | 430 (UNS S43000) | Higher Cr (16-18%), better corrosion resistance, similar formability |
| China | GB/T 4237 | 10Cr17 (equivalent to 430) | Higher Cr, widely used for trim and appliances |
| EU | EN 10088-2 | 1.4016 (X6Cr17) | Higher Cr, directly comparable to 430 |
| USA | ASTM A240 | 409 (UNS S40900) | Ti-stabilized, lower Cr (10.5-11.7%), better weldability, used in exhausts |
| Japan | JIS G 4304 | SUS 430 | Higher Cr, very common general-purpose ferritic |
Notes:
For welded constructions, a low interstitial (low C+N) variant or post-weld annealing is recommended to avoid sensitization and restore ductility. 429 is not intended for severely corrosive environments (e.g., marine, strong acids) or structural applications above 400°C due to possible 475°C embrittlement. Typical surface finishes include 2B, BA, and No. 4 per ASTM A480. When ordering, specify finish and edge condition.
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