304 vs. 430 stainless steel: what’s the difference?
Stainless steels vary in their elemental and chemical composition. They share many of the same characteristics, but their individual properties set them apart from each other. We’ve put together this guide to help you understand not only how these two grades are similar, but also how they differ. We’ll cover:
What is 304 stainless steel?
304 stainless steel belongs to the category of austenitic stainless steels. It comprises at least 18% chromium and between 8% to 10.5% nickel, with a carbon content of up to 0.08%.
Chromium is the crucial element that imparts superior corrosion resistance to stainless steel. It forms a passive oxide layer on the steel's surface, which protects it from rust and corrosion. Higher chromium content means better corrosion resistance. Chromium also improves the steel's toughness and ductility, making it easier to work with, and enables 304 stainless steel to withstand high temperatures.
Nickel further enhances corrosion resistance, especially in acidic environments. It also contributes to the material's toughness and ductility, making it easier to form and fabricate. Carbon, while adding strength and hardness to the steel, must be kept low to maintain corrosion resistance and ease of welding.
304 stainless steel also contains small amounts of manganese, silicon, and occasionally molybdenum. These elements enhance its strength, formability, and weldability.
Another notable feature of 304 stainless steel is its non-magnetic nature, which is advantageous in applications where magnetism is undesirable. This characteristic is due to its austenitic microstructure, which has a face-centered cubic (FCC) crystal structure. In this structure, the atoms are symmetrically arranged, and their magnetic moments cancel each other out.
You can learn more about stainless steel in our guide:
Compare 304 stainless steel with other grades in our expert guides:
What is 304 stainless steel used for?
This corrosion-resistant metal is commonly used in these applications:
| Industry | Typical applications | Why |
|---|---|---|
| Food processing equipment | Tanks, pipes and containers | Resistance to corrosion, easy to clean |
| Consumer appliances | Sinks, refrigerators, dishwashers | Durability, resistance to corrosion, aesthetic appeal |
| Automotive | Exhaust systems, trim and grilles | Resistance to corrosion, aesthetic appeal |
| Medical equipment | Surgical instruments, dental instruments and implants | Biocompatibility, resistance to corrosion and withstands high-temperature cleaning processes |
| Chemical processing equipment | Reactors, tanks and pipelines | Resistance to corrosion, stands up to a range of chemicals |
| Aerospace components | Aircraft structures, engines | High strength-to-weight ratio, resistance to corrosion, thermal stability |
304 stainless steel is also used in small components. Examples include:
Spring-loaded removable concealed hinges
- 304 used for base materials, pins are 303
- 304 for MTH1 series
- Mesh is 304
Properties of 304 stainless steel
The characteristics of 304 stainless steel – as with any material – are a result of its properties. Let’s take a closer look:
What is 430 stainless steel?
430 stainless steel is a member of the ferritic stainless steel grades, containing 17% chromium. In comparison, grade 304 has a slightly higher chromium content, with a minimum of 18%.
Unlike grade 304, grade 430 lacks nickel. This absence makes 430 stainless steel less effective in resisting corrosion and chemicals in harsh environments compared to 304 stainless steel. However, grade 430 still offers good corrosion resistance, just not to the same extent as grade 304. Additionally, the lack of nickel can make 430 stainless steel more prone to cracking during pressing.
Despite these differences, 430 stainless steel has good thermal conductivity, making it suitable for applications where heat dissipation is important. It also boasts slightly better heat resistance than 304 stainless steel, which can be advantageous in certain industrial applications.
Furthermore, 430 stainless steel is often more cost-effective than 304 stainless steel due to the absence of nickel, making it a popular choice for budget-conscious projects. It is commonly used in kitchen appliances, automotive trim, and other applications where its properties are sufficient. The material's excellent polishability also makes it an attractive option for decorative purposes.
Overall, while 430 stainless steel may not offer the same level of corrosion resistance as 304, its thermal properties, cost-effectiveness, and versatility make it a valuable material in various industries.
Unlike 304 stainless steel, 430 is magnetic – hence, why it’s ideal for magnetic catches, as seen here. Like 304, 430 stainless steel also has good formability. However, ultimately 304 stainless steel has more versatility in its applications, hence why it's the most widely used of all stainless steels.
What is 430 stainless steel used for?
430 stainless steel is significantly more affordable than 304 stainless steel, primarily due to the absence of nickel in grade 430. Although metal prices are subject to constant changes, it is common for grade 430 to be priced between 55% and 75% of the cost of 304 stainless steel.
Common applications for 430 stainless steel include the following:
| Industry | Typical application | Why |
|---|---|---|
| Automotive | Mufflers, trim | Corrosion resistance properties |
| Aircraft | Compressor blades | Corrosion resistance properties |
| Energy/power generation | Turbine engines | Corrosion resistant, maintains strength in heat |
| Consumer appliances | Refrigerator cabinet panels, range hoods, dishwasher linings | Cost effectiveness, easy to clean |
| HVACs | Heat exchangers, furnace parts | Thermal conductivity, Resistance to corrosion |
| Components | Fasteners/screws, Worm-drive hose clamp | Ease of fabrication, Resistance to corrosion |
Properties of 430 stainless steel
Both 304 and 430 have aesthetic appeal. Grade 430 has excellent finish properties, and coupled with its costs, it explains why it’s also used for decorative purposes, such as in elements of architecture and jewelry
340 vs 430 Stainless Steel: A comparison of these stainless steel grades
It helps to see the composition of these different grades of stainless steel. As you can see, they're similar in many ways, but grade 304 has a higher nickel content, which is one of the key differences between 340 vs 430 stainless steel.
| Element | 304 stainless steel % | 430 stainless steel % |
|---|---|---|
| Carbon | 0.07 | 0.08 |
| Chromium | 18.0 – 19.5 | 16 – 18 |
| Nickel | 8.0 – 10.5 | - |
| Silicon | 1.00 | 1.00 |
| Manganese | 2.00 | 1.00 |
| Phosphorous | 0.045 | 0.045 |
| Sulfur | 0.015 | 0.015 |
| Nitrogen | 0.10 | - |
Steel strength
Both of these steels have high strength. Grade 430 contains slightly more carbon, which means it should be stronger than 304. That said, the nickel in grade 304 contributes to its strength. Here's how their mechanical properties compare – note, the ultimate tensile and tensile yield strengths measure the materials' resilience to tensile (pulling) forces. The yield strength reflects the maximum stress before the material will deform permanently. The ultimate tensile strength describes maximum stress before fracture.
In the context of 340 vs 430 stainless steel, both grades are robust and durable, but their differences in composition lead to variations in their performance and applications. The presence of nickel in grade 304 enhances its overall strength and corrosion resistance, making it suitable for a wider range of environments compared to grade 430.
To understand the Rockwell B hardness test, see our guide, What’s shore hardness and why should you care?
| Properties | 304 stainless steel | 430 stainless steel |
|---|---|---|
| Ultimate Tensile Strength | 73,200 psi | 75,000 psi |
| Tensile Yield Strength | 31,200 psi | 50,000 psi |
| Hardness (Rockwell B) | 70 | 85 |
| Elongation at Break | 70% | 25% |
Properties of each steel
In summary, these are the primary characteristics of both steels. Both of these common grades have excellent corrosion resistance. Grade 430 has magnetic properties which is an important consideration for various industries. With their high formality they are durable for industrial applications.
| Characteristics | 304 stainless steel | 430 stainless steel |
|---|---|---|
| Corrosion resistance | Excellent | Very high |
| Magnetic | No | Yes |
| Weldability | High | Limited |
| Hardens during cold forming | Yes | No |
| Formability | Very good | Good |
| Machinability (annealed) | Fair | Good |
| Resistance to elevated temperatures | High | High |
| Maximum intermittent service temperature | 1562°F | 1562°F |
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