Stainless Steel 321 vs 304 – What’s the Difference

Stainless Steel 321 vs 304

Stainless steel is an essential material in various industries for its durability, corrosion resistance, and easy maintenance. From kitchenware to aerospace components, stainless steel finds its usage everywhere. However, with so many types of stainless steel available, it can take time to determine the ideal choice for your project. This blog will compare two frequently used stainless steel types – 321 and 304.

Difference Between Stainless Steel 321 and 304

Basic Properties

The primary difference between 321 and 304 stainless steel lies in their composition. While both metals have excellent corrosion resistance and weldability, their alloy composition distinguishes them. 321 stainless steel contains more titanium, while 304 has more chromium. This makes 321 more heat resistant and best suited for high-temperature applications. On the other hand, 304 has better resistance to deeply embedded corrosives and is more suitable for applications in harsh conditions.

Strength and Toughness

Despite being stainless steel, 321 and 304 differ in strength and toughness. The presence of titanium in 321 makes it more ductile and softer, giving it better resistance to deformation. Meanwhile, 304 has higher tensile strength, making it more suited for heavy-duty operations that require more holding strength.

Cost and Availability

Another critical factor that comes into play while comparing stainless steel types is the cost and availability. As 304 stainless steel has been around for a long time and is more commonly used, it is more practical to obtain, and the pricing is generally more affordable. However, 321 is a more specialized alloy best suited for high-temperature applications, making it more expensive and harder to find.

Cyclic Temperature Resistance

Cyclic temperature resistance refers to a metal’s ability to resist deformation and corrosion when exposed to temperature changes. While 321 and 304 have excellent corrosion resistance, 321 is better suited for cyclic temperature changes. This makes 321 an ideal choice for aircraft exhaust systems and heat exchanger applications.

Magnetic Properties

Finally, it’s important to note that 304 stainless steel is non-magnetic, while 321 is slightly magnetic. This difference primarily arises due to the presence of titanium in 321. While this may only sometimes be a significant factor in choosing stainless steel for a project, it’s essential to remember when working with sensitive applications involving electromagnetic equipment.


In conclusion, 321 and 304 stainless steel have unique properties, making them suitable for various applications. 321 is a specialized alloy best suited for high-temperature resistance and cyclic temperature changes, while 304 is more versatile and resistant to deeply embedded corrosives. Overall, understanding the differences between these two alloys can help you make an informed decision while choosing the ideal type of stainless steel for your project.



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