Contents
What is 430 Stainless Steel? Composition, Properties, and Applications
- John
This article discusses 430 stainless steel, focusing on its composition, properties, and applications. It highlights the alloy’s 16-18% chromium content and low carbon levels, along with its mechanical properties such as tensile strength and corrosion resistance. This article covers processing methods, including rolling and annealing, and provides welding guidelines.
What is 430 Stainless Steel
430 stainless steel(430 ss or 1.4016) is a ferritic steel, this alloy steel is composed of 16-18% chromium and less than 0.12% carbon, often referred to as “straight chromium” steel. It is typically available in solid forms like sheets and bars. Known for good corrosion resistance and formability, it is used in applications such as dishwasher linings, refrigerator panels, and automotive trim. Processing methods include hot and cold rolling. Variants include 430F for improved machinability and 434 with added molybdenum. Equivalent grades include 1.4016 (EN) and SUS 430 (JIS).
Variants of 430 Stainless Steel
430
430 is the standard ferritic stainless steel. It is resistant to corrosion and has nice formability.
Tensile Strength: 450 MPa
Yield Strength: 205 MPa
Elongation: 22%
Hardness: Rockwell B 89
Applications: Household appliances, automotive trims, chimney liners.
430F
430F is a free-machining variant of 430, designed for enhanced machinability through the addition of sulfur.
Tensile Strength: 552 MPa (typical)
Yield Strength: 379 MPa (typical)
Elongation: 25% (typical)
Hardness: Brinell 262
Applications: High-speed machining, automatic screw machines.
434
434 is a molybdenum-bearing version of 430, offering superior corrosion resistance, particularly in chloride environments.
Improved Corrosion Resistance: Enhanced against chlorides and acids.
Mechanical Properties: Similar to 430 with slightly higher strength.
Applications: Industrial applications with higher corrosive exposure.
Characteristics of 430 Stainless Steel
Corrosion Resistance: 430 stainless steel has nice corrosion resistance in many environments like dry or non-acidic situations. It can resist most organic acids, organic oxides, and moisture but performs poorly in strong acid, alkaline, and salty environments.
Magnetic Properties: 430 stainless steel is magnetic; this characteristic sets it apart from austenitic stainless steel, such as 304ss.
Hardness and Strength: This steel has relatively high hardness and strength, so it is ideal for many situations requiring nice mechanical properties.
Oxidation Resistance: With its higher chromium content, 430 stainless steel shows strong oxidation resistance in general atmospheric conditions, effectively resisting oxidation and surface rust.
Wear Resistance: The high hardness of 430 stainless steel provides good wear resistance, suitable for applications requiring high durability.
Low-Temperature Performance: 430 stainless steel performs well in low-temperature environments, maintaining stability and avoiding brittleness, which makes it suitable for refrigeration and freezing equipment.
Thermal Conductivity: It has better thermal conductivity than austenitic stainless steels such as 304.
Economic Feasibility: The production cost of 430 stainless steel is relatively low due to the absence of expensive alloying elements like nickel.
Machinability: 430 stainless steel is easy to process and form, making it suitable for many industrial manufacturing processes.
Decorative Appeal: we can polish its surface and treat it to achieve nice gloss and decorative effects.
attention: 430 stainless steel‘s corrosion resistance and high-temperature performance are not as good as high-alloy stainless steel like 304.
Composition of 430 Stainless Steel
Below is the chemical composition of 430 ss and its variants, including 430F and 434. Each variant is optimized for specific properties and applications by adjusting elements like carbon, manganese, sulfur, and molybdenum.
| Element | 430 (%) | 430F (%) | 434 (%) |
| Carbon (C) | ≤ 0.12 | ≤ 0.12 | ≤ 0.12 |
| Manganese (Mn) | ≤ 1.00 | ≤ 1.25 | ≤ 1.00 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 | ≤ 0.060 | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 | 0.15 | ≤ 0.030 |
| Chromium (Cr) | 16.00 – 18.00 | 16.00 – 18.00 | 16.00 – 18.00 |
| Nickel (Ni) | ≤ 0.75 | – | ≤ 0.50 |
| Molybdenum (Mo) | – | – | ≤ 0.75 |
Properties of 430 Stainless Steel
Physical Properties
| Property | Metric Value | Imperial Value |
| Density | 7750 kg/m³ | 0.280 lb/in³ |
| Elastic Modulus | 200 GPa | 29,000 ksi |
| Thermal Conductivity (at 100°C) | 26.1 W/m·K | 15.1 BTU/(hr·ft⋅°F) |
| Thermal Conductivity (at 500°C) | 26.3 W/m·K | 15.2 BTU/(hr·ft⋅°F) |
| Specific Heat Capacity | 460 J/kg·K | 0.110 BTU/(lb·°F) |
| Thermal Expansion Coefficient (0-100°C) | 10.4 µm/m·°C | 5.8 x 10⁻⁶ in/in/°F |
| Thermal Expansion Coefficient (0-315°C) | 11.0 µm/m·°C | 6.1 x 10⁻⁶ in/in/°F |
| Thermal Expansion Coefficient (0-538°C) | 11.4 µm/m·°C | 6.3 x 10⁻⁶ in/in/°F |
| Electrical Resistivity | 600 nΩ·m | 600 nΩ·m |
Mechanical Properties
430 Stainless Steel
| Property | Metric Value | Imperial Value |
| Tensile Strength | 483 MPa | 70 ksi |
| Yield Strength | 310 MPa | 45 ksi |
| Elongation | 22% | 22% |
| Brinell Hardness (HB) | 183 | 183 |
| Rockwell Hardness (HRB) | 85 | 85 |
| Elastic Modulus | 200 GPa | 29,000 ksi |
430F Stainless Steel
| Property | Metric Value | Imperial Value |
| Tensile Strength (typical) | 552 MPa | 80 ksi |
| Yield Strength (typical) | 379 MPa | 55 ksi |
| Elongation (typical) | 25% | 25% |
| Brinell Hardness (HB) (typical) | 262 | 262 |
| Elastic Modulus | 200 GPa | 29,000 ksi |
Corrosion Resistance
430 stainless steel has nice corrosion resistance, especially against organic acids and nitric acid. Its low carbon content ensures excellent resistance to intergranular corrosion, preventing carbide precipitation at grain boundaries. It is suitable for applications that maintain the material’s mechanical properties is crucial while resisting corrosion. Additionally, 430 stainless steel has good stress corrosion cracking resistance and is effective against various acids.
430 stainless steel provides comparable pitting and crevice corrosion resistance to 304 stainless steel when polished. It can withstand oxidation up to 870°C during periodic use and up to 815°C during continuous use. These properties make it ideal for household appliances, automotive trim, and other applications requiring robust corrosion resistance and durability.
Heat Resistance
430 stainless steel has nice heat resistance, it is adaptable in environments with high temperatures. It can resist oxidation up to 870°C (1598°F) during periodic use and up to 815°C (1499°F) during continuous use. It is well-suited for automotive exhaust systems and other parts that are subjected to high temperatures.
Oxidation Resistance
430 stainless steel has good oxidation resistance because of its high chromium. It can maintain its structural integrity and resist scaling in high-temperature environments. This property is very important for applications that require prolonged exposure to heat, such as industrial furnaces and heat exchangers.
Brittleness and Annealing
430 stainless steel tends to become brittle when exposed to temperatures in the range of 400-600°C (752-1112°F) for extended periods. This brittleness can be mitigated through annealing processes. Solution annealing involves heating the material to 815-845°C (1499-1553°F), followed by slow furnace cooling and air cooling, which helps dissolve chromium carbides and restore ductility. Sub-critical annealing, performed by heating to 760-815°C (1400-1499°F) and then air cooling or water quenching, relieves internal stresses without significantly altering mechanical properties.
Heat Treatment
430 stainless steel can’t be hardened by heat treatment. It is a ferritic stainless steel that retains its mechanical properties and corrosion resistance through specific heat treatment processes rather than hardening.
Solution Annealing
Solution annealing is performed by heating the material to 815-845°C (1499-1553°F), followed by slow furnace cooling to 600°C (1112°F), and then air cooling. This process helps to dissolve any chromium carbides and restore the material’s corrosion resistance and ductility.
Sub-Critical Annealing
Sub-critical annealing involves heating 430 stainless steel to 760-815°C (1400-1499°F) and then air cooling or water quenching. This process relieves internal stresses without significantly affecting the material’s mechanical properties.
430 Stainless Steel Common Forms
Sheets and Plates
Sheets and plates are flat-rolled products available in various thicknesses. They are frequently used in appliances, automotive trim, construction panels, and food processing equipment.
Coils
Coils are long strips of stainless steel wound into large rolls. They are suitable for fabrication into components like kitchen sinks, architectural trim, and industrial equipment.
Bars
Bars come in solid pieces with round, square, or rectangular cross-sections. They are used in the production of fasteners, machinery components, and structural parts.
Pipes and Tubes
Pipes and tubes are hollow cylindrical forms of stainless steel. They are widely used in liquid conveyance systems, thermal exchangers, and construction applications.
Wire
Wire consists of thin, flexible strands of stainless steel. It is used in the production of springs, wire mesh, lashing wires, and other fastening devices.
Strips
Strips are narrow, flat pieces cut from coils. They are often used in the automotive industry for trim and molding, or in the production of small precision components.
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Machining and Fabrication of 430 Stainless Steel
Machinability Compared to Austenitic Grades
430 stainless steel is easier to machine than austenitic grades like 304, but it is prone to galling. The 430F variant, with its higher sulfur content, offers improved machinability, making it ideal for high-speed machining operations.
Production Processes
- Melting and Casting: Raw materials(iron, chromium, carbon, etc) are melted in an electric arc furnace and cast into slabs.
- Hot Rolling: Slabs are heated and rolled to reduce thickness and form hot-rolled coils or sheets.
- Annealing: The hot rolled steel is heated to 815-845°C and slowly cooled to relieve stresses and improve ductility.
- Pickling: Acid treatment removes oxides and scale, improving surface cleanliness.
- Cold Rolling: Steel is processed through cold rolling to reach the desired gauge and texture.
- Final Annealing: Additional annealing optimizes the balance between mechanical properties and corrosion resistance.
- Pickling and Passivation: Final acid treatment and passivation enhance surface cleanliness and corrosion resistance.
- Finishing: Cutting, trimming, and surface treatments prepare the steel for specific applications.
Work Hardening Rate
430 stainless steel has a low work hardening rate, allowing for easier cold working compared to austenitic steels. This makes it suitable for bending and forming operations without significant increases in hardness.
Ductility and Cold Heading
The material has good ductility, making it suitable for less rigorous cold-heading applications. However, extreme cold work may require sub-critical intermediate annealing to maintain ductility and prevent brittleness.
Welding
430 stainless steel can be welded, although certain precautions and treatments are necessary to ensure the best results.
Preheat and Post-Weld Annealing
Preheat: It is recommended to preheat the steel to 150-200°C (302-392°F) to minimize the risk of cracking.
Post-Weld Annealing: Post-weld annealing at 790-815°C (1454-1499°F) can help relieve stresses and restore ductility. However, grain refinement will not occur.
Recommended Filler Rods
Filler Rods: For welding 430 stainless steel, the use of 430, 308L, 309, and 310 filler rods is recommended, depending on the specific application.
Key Considerations
Avoid Overheating: Avoid overheating to prevent excessive grain growth, which can lead to brittleness.
Clean Surface: Ensure the surface is clean before welding to prevent contamination.
Controlled Cooling: Control the cooling rate after welding to avoid the formation of unwanted microstructures.
Applications of 430 Stainless Steel
Household Appliances
Suitable for dishwasher linings, refrigerator panels, stove trim rings, chimney liners, and element supports due to its corrosion resistance and durability.
Automotive Industry
Ideal for trim and molding, lashing wires, exhaust systems, fuel tank components, and fasteners because of its bright finish, high-temperature resistance, and corrosion resistance.
Construction
Used in roofing, cladding, gutters, wall panels, door and window frames, and interior decor for its weather resistance, strength, and aesthetic appeal.
Food and Beverage Industry
Perfect for sinks, countertops, processing equipment, storage tanks, dispensing equipment, and cutlery due to its nice corrosion resistance, hygiene, and ease of cleaning.
Chemical Industry
Essential for nitric acid plants, heat exchangers, chemical storage tanks, pipes, and fume hoods because of its resistance to nitric acid and various chemicals.
Possible Alternative Grades of 430 Stainless Steel
| Grade | Core Feature | Key Characteristics |
| 430F | Free Machining | Easier to machine than 430 due to higher sulfur content and slightly lower corrosion resistance. |
| 434 | Molybdenum-Bearing | Stronger pitting and crevice corrosion resistance than 430, due to the addition of molybdenum. |
| 304 | Austenitic Grade | Higher corrosion resistance and better weldability and formability than 430. |
| 316 | Molybdenum-Bearing Austenitic Grade | Superior corrosion resistance in chloride environments, better weldability and formability than 430. |
| 3CR12 | Utility Ferritic | Lower corrosion resistance but more cost-effective for less critical applications. |
430 vs. 304 Stainless Steel: Differences Between These Two Steel
| 304 | 430 | |
| Corrosion Resistance | Higher corrosion resistance | Good corrosion resistance, but not as high as 304 |
| Formability and Weldability | Better for welding and forming | Less suitable for welding and forming compared to 304 |
| Cost | More expensive | More cost-effective |
| Tensile Strength | 515 MPa | 450 MPa |
| Yield Strength | 205 MPa | 310 MPa |
| Hardness (Brinell) | 201 | 183 |
| Elongation | 40% | 22% |
| Chromium (Cr) | 18-20% | 16-18% |
| Nickel (Ni) | 8-10.5% | ≤ 0.75% |
| Carbon (C) | ≤ 0.08% | ≤ 0.12% |
| Typical Applications | More demanding environments | Less corrosive environments |
