“
JIS SUS430 Stainless Steel: Ferritic Grade for Cost-Effective Corrosion Resistance & Decorative Applications
JIS SUS430 stainless steel, a ferritic grade equivalent to ASTM 430 and UNS S43000, is the most widely used chromium-only stainless steel due to its 16-18% Cr content. Offering moderate corrosion resistance, excellent formability, and superior thermal conductivity compared to austenitic grades, SUS430 is ideal for automotive trim, kitchen appliances, and architectural applications where cost efficiency and aesthetic appeal are prioritized. This article explores its chemical composition, mechanical properties, processing characteristics, and optimal use cases.
1. Chemical Composition (JIS G4305 Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | ≤ 0.12% | Low carbon minimizes carbide precipitation during welding/heat treatment |
| Chromium (Cr) | 16.00 – 18.00% | Primary alloying element forming protective Cr₂O₃ passive film |
| Manganese (Mn) | ≤ 1.00% | Enhances hot workability; residual element from steelmaking |
| Silicon (Si) | ≤ 1.00% | Improves oxidation resistance; acts as deoxidizer during melting |
| Phosphorus (P) | ≤ 0.040% | Impurity controlled to maintain ductility and weldability |
| Sulfur (S) | ≤ 0.030% | Minimized to prevent hot shortness during rolling/forging |
| Nickel (Ni) | ≤ 0.75% | Residual element; absence defines ferritic microstructure |
2. Mechanical Properties (Annealed Condition)
- Tensile Strength (σb): ≥ 450 MPa (JIS G4305 minimum requirement)
- Yield Strength (σ0.2): ≥ 205 MPa (sufficient for structural applications)
- Elongation (δ): ≥ 22% (lower than austenitic grades but adequate for forming)
- Hardness (HB): ≤ 183 (Brinell); softer than martensitic grades for easier machining
- Thermal Conductivity: ~26 W/m·K (30% higher than 304 stainless steel)
- Coefficient of Thermal Expansion: 10.4 µm/m·°C (20-100°C range)
3. Manufacturing & Processing Characteristics
- Melting Practice: Electric arc furnace (EAF) with AOD refining to achieve low carbon and nitrogen levels, preventing embrittlement.
- Hot Rolling: Conducted at 900-1100°C followed by air cooling; avoids grain coarsening that reduces ductility.
- Cold Rolling: Requires intermediate annealing (750-850°C) for thickness reductions >50% to restore ductility.
- Annealing: Full annealing at 780-850°C with slow cooling to relieve internal stresses and optimize corrosion resistance.
- Surface Finishing: Common finishes include 2B (cold-rolled, bright annealed), BA (bright annealed), and No.4 (brushed) for decorative applications.
- Welding Considerations: Requires preheat (150-200°C) and post-weld annealing to prevent grain growth in the heat-affected zone (HAZ).
4. Key Application Sectors
Automotive Components
Exhaust systems (non-high-temperature sections), trim moldings, wheel covers, and interior decorative panels — valued for corrosion resistance and formability.
Kitchen Appliances & Utensils
Refrigerator liners, dishwasher tubs, microwave oven cavities, and cutlery — meets food hygiene standards while offering cost savings over 304 grade.
Architectural & Interior Design
Elevator panels, wall cladding, ceiling tiles, and decorative trim — preferred for its bright, reflective surface and resistance to atmospheric corrosion.
Industrial Equipment
Nitric acid tanks (≤10% concentration), chemical processing equipment, and heat exchanger tubes — suitable for mildly corrosive environments.
5. Comparison with Related Grades
| Grade | Type | Key Properties | Typical Applications |
|---|---|---|---|
| SUS430 | Ferritic | 16-18% Cr, no Ni; cost-effective, magnetic, moderate corrosion resistance | Automotive trim, appliances, decorative architectural elements |
| SUS304 | Austenitic | 18% Cr, 8% Ni; superior corrosion resistance, non-magnetic, higher cost | Food processing, chemical equipment, marine applications |
| SUS430LX | Ferritic | Low C/N, Ti/Nb stabilized; improved weldability and formability | Deep-drawn automotive parts, welded assemblies |
| SUS444 | Ferritic | 18% Cr, Mo added; enhanced pitting resistance, higher temperature stability | Hot water tanks, solar water heaters, exhaust systems |
6. Selection Guidelines & Limitations
- Corrosion Resistance: Not suitable for chloride environments (e.g., coastal areas, swimming pools) or strong acids — consider SUS316 for such conditions.
- Forming Operations: Avoid sharp bends (minimum bend radius = 2×thickness); use lubricants to prevent galling during deep drawing.
- Welding Protocol: Use ER430 or ER309L filler metal; limit heat input to prevent HAZ embrittlement; post-weld annealing recommended.
- Temperature Limits: Avoid prolonged exposure above 400°C to prevent 475°C embrittlement; maximum service temperature ~760°C in air.
- Surface Protection: Passivation (citric or nitric acid treatment) enhances corrosion resistance after fabrication.
7. Request a Quote for JIS SUS430 Stainless Steel
For customized JIS SUS430 stainless steel products including coils, sheets, strips, or precision-cut parts, contact our technical sales team. We provide mill-certified material with full traceability and competitive pricing for global industrial applications.
“