How to manufacture stainless steel Welded Pipe and Tube?
In the nineteenth century, rolling mill technology was the only technique used to manufacture steel pipe for industrial purpose. This rolling technique involved long procedures. The rolled strips of sheet were formed into a circular cross section with the help of funnel rolls. The lap welding was then done on these rolled strips through the forge welding process. Today, with the advent of development and technology, various processes came into existence for the manufacturing of stainless tubes and pipes.
Stainless steel tube/pipe has excellent resistance to stain or rust due to its chromium content, usually from 12 to 20 percent of the alloy. In the current steel market, you can often find types of stainless steel pipe for a variety of applications. As a rule, there are two manufacturing methods for producing pipe. They can be produced from large coils of strip or skelp, which is welded without interruption. This is called continuous production. Or they can be produced in large sizes, one piece at a time, which is called batch production.
As a professional steel pipe manufacturer in India, we would like to talk more about the manufacturing of stainless pipe in a mill specifically.
For batch production, the plate at the pipe mill is cut to the correct length and width for the pipe size to be manufactured. First, the edges of the plate are formed to provide for the correct geometry in the weld. Then the whole pipe is roll-formed to provide the cylindrical shell for welding. After the shell is rolled, the joint is tack welded to hold the shell together until the final welding operation. The shell is then transferred to the welding machine.
In-line bead rolling
In continuous production, each weld is cold worked so that subsequent heat treatment will produce a grain refinement in the weld structure, which provides for a superior profile of the weld in cross section, both inside and out. A rolling mandrel inside the pipe supports the section being rolled, which holds the mandrel in the right place to support the bead working.
Annealing recrystallizes the stainless steel’s internal structure, which is altered in the rolling process. In continuous production, pipe is annealed in line followed immediately by water quenching. All continuously produced pipe is in-line annealed.
Continuous pipe is cut in desired lengths by a special device which monitors the length produced and then locks on to the pipe and travels with it to cut off the desired length without interrupting its smooth movement. Each piece of pipe is inscribed with an identification indicating the original heat and lot of coil.
The cold forming, welding, and rapid cooling of continuously produced pipe may produce some distortion, so the next step is a mechanical straightening.
Test samples are cut from the pipe as required. The number of samples, their location, and exactly which tests are done vary based on what the customer has requested in the ordering specification. We may be required to test for composition, strength, hardness, toughness, and corrosion resistance. On the pipe itself we also perform a number of non-destructive tests such as hydro, eddy current testing, and x-ray examination to confirm weld integrity.
For more information, you can refer to the article “Welded Steel Pipe Classification”.
Scoda Tubes Limited is one of the leading Manufacturers and Exporters of Stainless Steel Pipes and Tubes in India. We mainly produce Stainless Steel Seamless & Welded – Pipes, Tubes, Heat Exchanger Tubes, High Precision and Instrumentation Tubing.
We have the expertise to manufacture Seamless Stainless Steel Tubing with assuring Quality of Closer Dimensional Tolerances and higher corrosion resistance Stainless Steel Seamless Tube. We use the finest quality of raw material to produce Stainless Steel Heat Exchanger Tubes which ISO, IBR, EIL, and OHSAS certified.
We are also one of the largest Stainless Steel Seamless Pipe exporters from India. We provide Stainless Steel Seamless Pipe in different NB Sizes, Schedule sizes, and Grades as per customer’s requirements.
Our Stainless Steel manufacturing unit is capable of producing large and customized order from our client around the world. Mail us for more information about our stainless Steel Seamless and Welded – Pipes, Tubes, and Heat Exchanger Tubes.