Duplex Stainless Steel vs Stainless Steel – What’s the Difference

Duplex Stainless Steel vs Stainless Steel

For most people, stainless steel is the epitome of shiny and durable material, but do you know there’s a type of steel that is stronger and more corrosion-resistant than the typical stainless steel? That’s right – it’s called duplex stainless steel. Today, we will dive into the details and differences between these two types of steel.

Difference Between Duplex Stainless Steel and Stainless Steel

Definition and composition:

Stainless steel is a type of alloy steel, which means it’s made from a mixture of metals, including iron, carbon, and chromium. The percentage of each metal inclusion varies, depending on the grade. Meanwhile, duplex stainless steel, also known as austenitic-ferritic stainless steel, is a two-phase alloy of about 50% austenite and 50% ferrite. It also has a higher chromium and molybdenum content, making it more corrosion-resistant.

Strength and durability:

Due to its two-phase composition, duplex stainless steel is stronger than regular stainless steel. The ferrite phase gives it strength, while the austenite phase makes it more ductile and tough. It’s also less prone to cracking under stress than its counterpart. As a result, duplex stainless steel can be used in applications with higher strength and durability.

Corrosion resistance:

Both duplex stainless steel and regular stainless steel have good corrosion resistance. However, duplex stainless steel has better resistance to stress corrosion cracking, pitting, and crevice corrosion, particularly in environments containing chlorides and other corrosive chemicals. It’s also more resistant to high temperatures and acids, making it ideal for chemical and petrochemical industries.

Weldability and Fabrication:

Due to its two-phase composition, duplex stainless steel is slightly more difficult to weld than regular stainless steel. However, welding using appropriate techniques and filler materials is still possible. Additionally, duplex stainless steel can be easily formed, bent, and machined using conventional methods, making it a versatile material for fabrication.


Duplex stainless steel is more expensive than regular stainless steel due to its more complex composition and superior properties. However, when used in high-stress or harsh environments, its added strength and durability make it a more cost-effective option in the long run.


In summary, while stainless steel is a widely used material that offers excellent corrosion resistance, duplex stainless steel takes it up a notch with increased strength, durability, and corrosion resistance. Although it’s more expensive, it’s worth considering, especially in harsh environments. Hopefully, this article helped you understand the differences between these two types of steel and make a more informed decision for your next project.



Recent Posts