304 vs 430 Stainless Steel - What is the Difference？

Stainless steel is the most commonly used material in multiple components across different industries. However, it has different grades among which 304 stainless steel and 430 stainless steel are quite popular. If you are looking forward to gaining some understanding of 304 stainless steel vs 430 stainless steel, this guide below captures all the essential details. So let's read.

What is the Difference Between SUS 304 and 430?

SUS 304 and SUS 430 are the two grades of stainless steel and consist of different compositions. The SUS 304 is known as austenitic stainless steel and it comprises 8% nickel and 18% chromium with some other elements. SUS 430 on the other hand is called ferritic stainless steel and contains around 0.75% nickel and around 16 to 18% of chromium.

SUS 304 offers high strength, excellent formability, and corrosion resistance. It is very commonly used in different architectural applications, chemical containers, and kitchen equipment. SUS 430 is highly affordable and offers good machinability but is less resistant to corrosion. It is used in applications like automotive trim and such appliances where corrosion resistance is not a prime concern.

Comparing SUS 304 and SUS 430

Chemical Composition

The chemical composition of the two grades differs as given below:

304 Stainless Steel:

• Chromium: 17.5 to 19.5%
• Carbon: 0.07%
• Silicon: 1%
• Manganese: 2%
• Nickel: 8 to 10.5%
• Nitrogen: 0.10%
• Sulfur: 0.015%

430 Stainless Steel:

• Carbon: 0.08%
• Chromium: 16 to 18%
• Silicon: 1%
• Manganese: 1%
• Phosphorus: 0.045%
• Nickel: 0.075%
• Sulfur: 0.015%

Corrosion Resistance

304 Stainless Steel: It offers high corrosion resistance especially when used in environments rich in chloride and acidic chemicals because of its high content of nickel.

430 Stainless Steel: It is suitable for environments that are mildly corrosive and it does not have much corrosion resistance due to which it is also less effective against acids and chlorides.

Molecular Structure

304 Stainless Steel: The austenitic structure of stainless steel 304 comprises molecules arranged in face-centered cubic form having high amounts of nickel. Hence, it offers high ductility and corrosion resistance.

430 Stainless Steel: It has a ferritic structure with body-centered cubic molecules having either very little or no nickel. It adds to the magnetic properties of this grade of stainless steel.

Hardness

304 Stainless Steel: It is a soft metal that offers high ductility and is work-hardened.

430 Stainless Steel: It is less ductile and hard, it also offers moderate strength without any work-hardening.

Weldability and Formability

304 Stainless Steel: It offers seamless formability and weldability which makes it suitable for deep drawing and complex shapes.

430 Stainless Steel: It offers moderate formability and weldability, it is quite challenging to weld and form when compared to 304 stainless steel.

Magnetism

304 Stainless Steel: It is non-magnetic when in an annealed state.

430: Stainless Steel: It has a ferritic structure which makes it magnetic.

Welding

304 Stainless Steel: It is easily weldable using all types of methods when not subjected to pre- or post-weld heat treatment.

430 Stainless Steel: It can be welded but it may need post-weld heat treatment so that corrosion and brittleness are prevented.

Heat Resistance

304 Stainless Steel: It offers excellent oxidation resistance for up to 870 degrees centigrade.

430 Stainless Steel: It has an oxidation resistance of moderate level up to 815-degree centigrade.

Mechanical Properties

Cost Composition

304 Stainless Steel: It comprises 8% nickel which increases the cost of that grade.

430 Stainless Steel: Due to negligible or no amount of nickel in this grade it is relatively quite cheaper compared to 304 stainless steel.

Applications of SUS 304 and SUS 430

The applications of SUS 304 and SUS 430 are given below:

Stainless Steel 304

Stainless Steel 304 is used in environments in which durability, cleanliness, and high corrosion resistance are prime requirements. It is suitable for applications that involve exposure to chemicals, and moisture. Some of these applications comprise the following:

• Processing equipment for food and beverages
• Containers and tanks for chemicals
• Medical tools and surgical instruments
• Kitchen utensils, sinks and cookware
• Exhaust components of automobiles
• Bolts, nuts, and springs

Stainless Steel 430

Stainless Steel 430 is opted mostly for environments where corrosion resistance is not a concern and also where a cost-effective solution is required. It is suitable for indoor applications which require good formability. Some of these applications comprise the following:

• Surfaces of appliances
• Liners for dishwashers
• Decoratives
• Interior components and trims of automobiles

Conclusion

It is very crucial to understand the difference between these two grades of stainless steel so that you can choose a relevant one for your application. The guide above must have clarified the difference between SUS 304 and SUS 430. If you are looking forward to having the components of these grades custom-manufactured for your applications, you can get in touch with us at DEK.

FAQs

Are both 304 and 430 stainless steel food grade?

Yes, both 304 and 430 stainless steel are food grade.