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304 vs 430 Stainless Steel: Properties, Applications, Manufacturing Process
- John
304 and 430 are among the most common types of stainless steel. While they might appear alike, their distinct compositions and characteristics render them appropriate for various uses. So what is the difference between 304 and 430 stainless steel? If you’re feeling uncertain about which to choose, this guide will compare all the key information about 304 and 430 to help you select the best grade for your needs.
Meaning of 304 vs 430 Stainless Steel’s Grade
Steel grades indicate the composition and properties of the metal. The grade number reflects the material’s standard, corrosion resistance, and suitability for various uses. Grades like 304 and 430 are classified according to the American Iron and Steel Institute (AISI), which standardizes their composition and performance. Next, we’ll explain what the grades 304 and 430 specifically mean for stainless steel.
What is 304 stainless steel?
304 (18/8) stainless steel has a bright surface of 18% chromium and 8% nickel, with an austenitic structure. It offers excellent corrosion resistance, suitable for moist and chemical environments. Typically cold rolled for surface finish, it can also be hot rolled for thicker plates. Available in sheets, plates, and coils, 304 is widely used in culinary tools, food processing, and architecture. It is easily weldable, making it versatile for various fabrication methods.
What is 430 stainless steel?
The inox 430 (18/0) stainless steel has a matte surface, made of about 16-18% chromium, with a ferritic structure. It is ferromagnetic and offers good corrosion resistance. Commonly used in appliances, automotive trim, and kitchen utensils, it is typically processed by cold rolling and comes in sheets, plates, and strips. 430 stainless steel is difficult to weld due to its higher thermal conductivity and lower ductility compared to austenitic grades.
Is 430 Stainless Steel Magnetic?
Yes, 430 stainless steel is magnetic. Classified as ferritic stainless steel, it has a body-centered cubic (BCC) structure, which makes it naturally magnetic. In contrast, austenitic stainless steels like 304 are generally non-magnetic due to their face-centered cubic (FCC) structure.
Key Properties of 430 and 304 Stainless Steel
The characteristics of stainless steel impact its performance and suitability. Understanding the essential characteristics of 430 and 304 can assist you in selecting the appropriate material for your requirements.
Chemical Properties of 304 and 430 Stainless Steel
Although 304 and 430 are both stainless steels, their chemical compositions differ. Compare the following:
| Chemical Element | 304 Stainless Steel | 430 Stainless Steel |
| Iron (Fe) | Balance | Balance |
| Carbon (C) | ≤ 0.08% | ≤ 0.12% |
| Chromium (Cr) | 18-20% | 16-18% |
| Nickel (Ni) | 8-10.5% | – |
| Manganese (Mn) | ≤ 2.00% | ≤ 1.00% |
| Silicon (Si) | ≤ 1.00% | ≤ 1.00% |
| Phosphorus (P) | ≤ 0.045% | ≤ 0.04% |
| Sulfur (S) | ≤ 0.030% | ≤ 0.03% |
| Nitrogen (N) | ≤ 0.10% | – |
Chromium Content: 304 has slightly higher chromium, which enhances its corrosion resistance, making it better for harsh environments.
Nickel Content: The nickel in 304 enhances its resistance to corrosion, flexibility, and welding capability. 430 contains no nickel, making it cheaper but with lower corrosion resistance.
Carbon Content: 430 has slightly more carbon than 304, making it more prone to rust and less suitable for welding.
Manganese and Silicon: Both grades have similar amounts of manganese and silicon, contributing to overall strength and workability.
Nitrogen Content: 430 lacks nitrogen, meaning it doesn’t have the added strength and corrosion resistance found in 304.
304 contains a higher nickel content, which improves corrosion resistance but increases its cost. In contrast, 430 is nickel-free, making it more affordable but also more prone to corrosion. However, 430 is magnetic and better suited for applications requiring magnetism, offering a cost-effective option for less corrosive environments.
Corrosion Behavior of 304 vs. 430 Stainless Steel
304 Stainless Steel: Prone to pitting and crevice corrosion in chloride-rich environments, particularly in warm conditions. It can also suffer from stress corrosion cracking at temperatures above 60°C (140°F).
430 Stainless Steel: More vulnerable to pitting and crevice corrosion than 304 in chloride environments. However, it has better resistance to stress corrosion cracking, especially up to 60°C, though extreme conditions can still pose a risk.
Physical Properties of 304 and 430 Stainless Steel
304 and 430 stainless steels have differences in density, melting point, modulus of elasticity, and other physical properties. Below is a comparison:
| Physical Property | 304 Stainless Steel | 430 Stainless Steel |
| Magnetism | Non-magnetic | Magnetic |
| Density | 7.93 g/cm³ | 7.7 g/cm³ |
| Melting Point | 1400-1450°C (2552-2642°F) | 1425-1510°C (2597-2750°F) |
| Elastic Modulus | 193-200 GPa | 200 GPa |
| Thermal Conductivity | 16.2 W/m·K (at 100°C) | 23.9 W/m·K (at 100°C) |
| Thermal Expansion Coefficient | 16.0 x 10⁻⁶ /K | 10.4 x 10⁻⁶ /K |
Magnetism: 430 is magnetic, ideal for appliances and automotive trim. 304 is non-magnetic, better for electronics and medical equipment.
Density: 304 is denser, offering more strength, ideal for structural use. 430 is lighter, suited for weight-sensitive applications.
Melting Point: 430’s higher melting point suits high-temperature uses like exhaust systems. 304 works well in typical industrial and kitchen environments.
Modulus of Elasticity: 430 is stiffer, good for rigid applications. 304 is more flexible, ideal for bending and forming.
Thermal Conductivity: 430 conducts heat better, useful in heat exchangers. 304 retains heat, making it great for cooking and insulation.
Electrical Resistivity: 304 has higher resistivity, fitting for electronics. 430’s lower resistivity suits heating elements.
Thermal Expansion: 304 expands more with heat, useful for heat tolerance. 430 is more dimensionally stable, better for precise components.
Physical properties guide the applications of each stainless steel grade, but lower values don’t mean less usefulness. 304’s key traits are its non-magnetic nature and high corrosion resistance, ideal for kitchens and medical devices. 430 is magnetic with better thermal conductivity, suited for appliances and automotive parts.
Mechanical Properties of 304 and 430 Stainless Steel
Mechanical properties reflect how stainless steel deforms and breaks under stress, making them crucial for selecting and using the material. Below is a comparison of the main mechanical properties of 304 and 430 stainless steels.
| Mechanical Property | 304 Stainless Steel | 430 Stainless Steel |
| Yield Strength | 205 MPa (30 ksi) | 275 MPa (40 ksi) |
| Tensile Strength | 505 MPa (73 ksi) | 450 MPa (65 ksi) |
| Elongation | 40-50% | 20-30% |
| Reduction of Area | 55% | 45% |
| Brinell Hardness | 201 HB | 187 HB |
| Weldability | Excellent | Good |
| Machinability | Moderate | Fair |
Yield Strength: 430 has a higher yield strength than 304, offering better resistance to deformation under stress.
Tensile Strength: 304 has a higher tensile strength than 430, meaning it can withstand greater force before breaking.
Elongation: 304 has a higher elongation than 430, allowing it to stretch more before breaking, which is beneficial for forming and bending.
Reduction of Area: 304 has a higher reduction of area compared to 430, enabling it to handle more deformation before breaking.
Brinell Hardness: 304 has slightly higher Brinell hardness than 430, making it harder and more resistant to surface wear.
Weldability: 304 offers excellent weldability, suitable for complex welding applications. 430 has good weldability but may require more care during welding.
Overall, 304 stainless steel is typically more flexible and harder, making it suitable for high-strength and welding applications. 430 stainless steel, with its greater yield strength and hardness, is perfect for uses needing deformation resistance and magnetic qualities. Each grade’s specific mechanical properties make it suitable for different uses.
Stamping Comparison of 304 vs. 430 Stainless Steel
304 Stainless Steel: Due to its higher ductility and toughness, 304 is ideal for deep drawing and complex stamping operations. It resists cracking and has better formability, making it suitable for more intricate shapes.
430 Stainless Steel: While 430 can be stamped, its lower ductility compared to 304 makes it more prone to cracking or tearing during complex stamping. It is better suited for simpler shapes and shallow drawing operations.
304 vs 430 Stainless Steel: Manufacturing Process
304 and 430 stainless steels have notable differences in their manufacturing process, including raw material selection, melting processes, rolling procedures, and subsequent treatments. Below is an overview of the typical processing methods for each grade.
Processing Method of 304 Stainless Steel
304 stainless steel is produced using several key steps:
- Raw Material Selection: Mainly using high quality iron ore, chromium and nickel.
- Melting: During the melting process, the proportion of alloying elements needs to be strictly controlled to ensure the homogeneity and purity of the composition.
- Casting: The liquid metal is poured into billets or slabs.
- Hot Rolling: Billets or slabs are hot-rolled to create sheets, plates, or coils.
- Cold Rolling: The hot-rolled product is further processed through cold rolling to attain the specified thickness and surface quality.
- Annealing: The cold-rolled steel is subjected to annealing in an oven to reduce stress and improve resistance to corrosion.
- Pickling and Passivation: The steel is cleaned using acid to remove oxides and enhance its surface quality.
These steps ensure that 304 stainless steel achieves its characteristic corrosion resistance, strength, and formability.
Processing Method of 430 Stainless Steel
430 stainless steel is processed through the following steps:
- Raw Material Selection: Iron ore, chromium and small amounts of alloying elements are chosen as raw materials for production, and nickel is hardly ever employed.
- Melting: The melting process is relatively simple and is usually reprocessed using recycled scrap iron and steel, which may contain more impurities.
- Casting: The liquid metal is molded into billets or slabs.
- Hot Rolling: The billets or slabs are hot-rolled to produce sheets, plates, or coils.
- Cold Rolling: The hot-rolled steel is processed through cold rolling to obtain the required thickness and surface finish.
- Annealing: The cold-rolled material is annealed to improve its magnetic properties and relieve stress.
- Pickling and Passivation: The steel is cleaned with acid to remove oxides and enhance its surface quality.
These processes ensure that 430 stainless steel maintains its magnetic properties and provides good performance for applications where magnetic characteristics are needed.
430 and 304 stainless steel in the production method, the main differences are reflected in the material composition, melting process, rolling and processing, mechanical properties, and application areas.
If you are interested in the basic production process of stainless steel, please click here.
Equivalent Grades and Standards for 304 and 430 Stainless Steel in Other Countries
304 Stainless Steel Equivalent Grades and Standards
| Country | Standard | Equivalent Grade |
| China | GB/T 3280 | 00Cr19Ni10 |
| USA | ASTM A240, A276 | Type 304 |
| UK | BS 1449, BS 970 | 304S31 |
| Japan | JIS G 4305, JIS G 4312 | SUS304 |
| International | ISO 683-2, ISO 4954 | X5CrNi18-10 |
430 Stainless Steel Equivalent Grades and Standards
| Country | Standard | Equivalent Grade |
| China | GB/T 4237 | 1Cr17 |
| USA | ASTM A240, A276 | Type 430 |
| UK | BS 1449, BS 970 | 430S29 |
| Japan | JIS G 4305 | SUS430 |
| International | ISO 683-2 | X6Cr17 |
Applications of 304 and 430 Stainless Steel
The unique properties of 304 and 430 stainless steels make them suitable for a variety of applications. Understanding their specific strengths helps in choosing the right material for different environments and uses. Here’s a look at where each grade is typically applied.
Applications of 304 Stainless Steel
| Industry | Applications | Why |
| Food Processing | Food and beverage processing equipment | High corrosion resistance and ease of cleaning |
| Kitchenware | Sinks, countertops, cookware | Non-reactive and durable surface, easy to clean |
| Medical | Surgical instruments, medical devices | High hygiene standards and corrosion resistance |
| Construction | Architectural panels, building facades, handrails | Aesthetic appeal and durability in various weather conditions |
| Chemical | Storage tanks, pipelines, chemical processing equipment | Excellent resistance to chemicals and corrosion |
| Marine | Marine equipment, boat fittings | Resists saltwater corrosion effectively |
| Automotive | Exhaust systems, trim components | High strength and resistance to heat |
| Pipelines | Water and gas pipelines | Good corrosion resistance and strength |
| Energy | Power generation equipment, reactor components | High strength and resistance to harsh conditions |
| Textiles | Dyeing and finishing equipment | Corrosion resistance to chemicals used in processing |
Applications of 430 Stainless Steel
| Industry | Applications | Why |
| Appliances | Oven linings, dishwasher interiors, refrigerator trims | Magnetic properties and resistance to heat and corrosion |
| Automotive | Automotive trim, exhaust systems | Good corrosion resistance and ability to hold up to wear |
| Construction | Wall cladding, roofing sheets | Good appearance and durability in architectural elements |
| Kitchenware | Cookware, sinks, and kitchen appliances | Cost-effective and decent corrosion resistance |
| Household | Bathroom fittings, door handles, and decorative trims | Cost-effective with good magnetic properties |
| HVAC | Air ducts, furnace parts | Good resistance to heat and corrosion |
| Industrial | Industrial equipment housings, machinery parts | Good durability and resistance to wear |
| Marine | Boat fittings, marine hardware | Corrosion-resistant in less aggressive marine environments |
304 stainless steel, With its superior corrosion resistance and non-magnetic characteristics, it is perfect for uses in food processing, medical devices, and kitchenware. However, its higher cost and lower magnetic properties make it less suitable for applications requiring magnetic properties, such as certain automotive or industrial applications.
430 stainless steel, known for its magnetic properties and good heat resistance, is well-suited for appliances, automotive trim, and household fittings. However, its lower corrosion resistance compared to 304 makes it less suitable for harsh chemical environments or applications exposed to severe weather conditions, such as marine or chemical processing equipment.
Should You Choose 304 or 430 Stainless Steel?
Considering practicality, here’s a straightforward guide:
- Cost: Choose 430 for a budget-friendly option, as it’s nickel-free and cheaper than 304.
- Magnetism: Opt for 430 if you need a magnetic material; 304 is non-magnetic.
- Weldability: 304 is better for welding applications; 430 is harder to weld.
- Applications:
- Food environments: 304 offers better corrosion resistance.
- Industrial and architectural: 430 suits less corrosive, cost-sensitive applications.
In summary, 304 is ideal for applications needing better corrosion resistance, weldability, and non-magnetic properties, especially in food and corrosive environments. 430 is a more affordable, magnetic option, suitable for cost-sensitive, less corrosive projects in industrial and architectural settings.
Will 430 stainless steel rust outside?
Yes, 430 stainless steel can rust outside, especially in harsh or salty environments due to its lower corrosion resistance compared to other grades.
Related Reading
Does Stainless Steel Rust?
Is 304 stainless steel ok for outside?
Yes, 304 stainless steel is suitable for outdoor use due to its good corrosion resistance, though it may still need occasional maintenance to prevent rusting in very harsh environments.
Does 304 stainless steel scratch easily?
304 stainless steel is relatively resistant to scratches but can be scratched under certain conditions. Its surface can be polished to reduce visible scratches.
How to check the quality of stainless steel 304?
You can check the quality by examining the material’s corrosion resistance, checking for certifications or test reports, and using a magnet (304 is non-magnetic).
Is 430 Stainless Steel Food Grade?
Yes, 430 stainless steel is considered food grade. It is commonly used in kitchen utensils and appliances because of its corrosion resistance and safety for contact with food. However, it is less resistant to corrosion than higher-grade stainless steel like 304.
Choose Your Stainless Steel Grade Now！
Selecting between 304 and 430 stainless steel relies on your particular needs and application demands. If high corrosion resistance and non-magnetic properties are required, 304 is the preferred choice. However, if you need magnetic properties and cost-effectiveness, 430 may be more suitable. Read more stainless steel articles on our blog page.
At SteelPRO Group, we specialize in providing high-quality stainless steel solutions that meet your needs. As a specialized steel supplier, we offer stainless steel in all shapes and sizes. Contact us to find the most suitable material for your project and benefit from our professional services.
