How to Properly Fabricate Duplex Steel Pipes for Optimal Performance

Duplex stainless steel pipes are some of the most durable and versatile for various industrial applications. They are designed with excellent corrosion resistance, high strength, and better toughness than most piping materials. However, as with any metallic material, proper fabrication is essential to ensure their performance and durability.

Suppose you are a plumbing contractor or running an industrial process that requires duplex steel piping. In that case, it is vital to understand the basics of fabricating duplex steel pipes to ensure optimal performance. This blog post will explore step-by-step guidelines on correctly fabricating duplex steel pipes for superior performance.

Choosing the Right Material

The first step in fabricating duplex steel pipes is choosing the right material to match your intended application. Duplex stainless steel pipes generally come in two categories: lean duplex (LDX) and super duplex (SDX). LDX has a lower nickel content, while SDX has a higher nickel content, and both have varying levels of chromium and molybdenum.

If your application involves corrosive or high-pressure fluids, consider super duplex stainless steel pipes, while a lean duplex is suitable for less demanding applications. It is essential to consult with your manufacturer or supplier to ensure that you get the right grade of duplex steel pipe for your specific application.

Duplex steel pipes are known for their exceptional strength and performance in various applications. When fabricating duplex steel pipes, it is essential to select the right material to ensure optimal performance. The optimal choice of material depends on the environment the pipe will be operating in, as well as any specifications or requirements of the project. Corrosion resistance is especially important; thus, an austenitic-ferritic grade stainless steel should be used for maximum corrosion resistance. Additionally, to achieve optimal ductility and formability, opting for lean alloys such as low carbon grades or stabilized grades (with Titanium/Niobium) is usually best. By carefully considering these factors while choosing your duplex pipe fabrication materials, you can rest assured that you’ll achieve long-term success with minimal maintenance required.

Cutting and Machining

Once you have the right material, the next step is cutting the pipe to size and preparing it for machining. Cutting duplex steel requires using proper cutting tools that are tough enough to handle the material’s hardness and flexibility.

It is essential to avoid using low-quality cutting tools as they can cause excessive heat generation, leading to the pipe’s cracking or warping. After cutting the pipe to the required size, the next step is machining the edges to smoothen them and adjusting the diameter if necessary.


Welding is crucial in fabricating duplex steel pipes as it affects the pipe’s integrity, durability, and corrosion resistance. Duplex steel welding requires specific skill sets and protocols to achieve optimal results. One of the primary challenges in welding duplex steel is avoiding intergranular corrosion.

Intergranular corrosion can occur when welding heat affects the material’s microstructure, forming chromium carbides. Welding requires precise heat input and temperature control to ensure that the steel’s chemical balance remains stable.

Finishing and Testing

After welding, finishing the pipe’s surface is essential to remove any weld splatters, spatter, and material contaminants. Finishing also involves polishing or buffing the surface to achieve the desired surface finish.

Once the pipe is finished, it goes through rigorous testing to ensure it meets the required standards for your application. Some standard tests for duplex steel pipes include hydrostatic, dye penetrant, and ultrasonic testing to ensure no weld defects, leaks, or cracks.

Proper Handling and Maintenance

Finally, after fabrication, proper handling and maintenance are crucial to ensure optimal performance and longevity of duplex steel pipes. Handling duplex steel pipes requires proper care to prevent bending, scratches, or deformation that can affect their integrity.

Maintaining duplex steel pipes involves regular cleaning, inspection, and repairs as necessary. Proper maintenance can increase the pipes’ lifespan, prevent leaks, and ensure they meet the required safety and quality standards.


Proper fabrication of duplex steel pipes requires following strict guidelines to ensure their performance and durability in different industrial applications. Every step is critical in ensuring optimal performance, from choosing the right material to proper machining, welding, finishing, testing, and maintenance. Taking these steps carefully guarantees duplex steel pipes that will meet your requirements, reduce downtime, and optimize your overall operating costs.

How to Properly Fabricate Duplex Steel Pipes for Optimal Performance

by Amco Metals time to read: 3 min