Due to the mature technology of stainless steel welded pipes, they have replaced seamless pipes in many fields such as wineries, petroleum, food, automotive, papermaking, and air conditioning, and are widely used. The market demand for stainless steel seamless pipes is concentrated in basic industries; relevant data shows that petroleum, chemical, and power generation account for one-third of the total consumption of stainless steel seamless pipes. The production methods for stainless steel seamless pipes include hot rolling, hot extrusion, cold rolling, and cold drawing. In recent years, due to advancements in continuous casting and rolling technology and the application of various new welding technologies and non-destructive testing techniques, the quality of stainless steel welded pipes has continuously improved, allowing them to partially replace stainless steel seamless pipes in various application fields, and at a price approximately 20% lower than seamless pipes. With the development of the automotive industry, the use of stainless steel welded pipes in the automotive sector is becoming increasingly widespread, especially in engine high and low-pressure oil pipes, cooling water pipes, and exhaust pipes. Some mid-to-high-end cars have already switched to using 3-series stainless steel welded pipes. Why are more and more manufacturers choosing stainless steel welded pipes?
This depends on the characteristics and advantages of stainless steel welded pipes themselves. First, let’s look at the manufacturing process of small-diameter stainless steel welded pipes: steel plate > slitting > forming > welding > bright solution treatment > internal and external weld bead treatment > eddy current testing > laser diameter measurement > straightening > warehousing. From the manufacturing process, we can see that stainless steel welded pipes are produced continuously online. The thicker the wall of the stainless steel welded pipe, the greater the investment in the unit and welding equipment, and the less economical and practical it becomes. The thinner the wall of the stainless steel welded pipe, the lower its input-output ratio will be. Secondly, the manufacturing process of stainless steel welded pipes determines its advantages and disadvantages. Generally, stainless steel welded pipes have high precision, uniform wall thickness, high internal and external surface brightness, and can be cut to any length. Therefore, it demonstrates its economy and aesthetics in high-precision, medium- and low-pressure fluid applications. The manufacturing process of seamless pipes is: smelting > ingot > rolling > sawing > peeling > piercing > annealing > pickling > dusting > cold drawing > cutting > pickling > warehousing. It can be seen that, besides the advantages of thick-walled, high-pressure, and high-strength mechanical structures, seamless steel pipes generally have low precision: uneven wall thickness, low gloss on the inner and outer surfaces, high cost per length, and pitting and black spots on the inner and outer surfaces that are difficult to remove.
If this is still not clear enough, we can look at it this way:
1. Coverage Range: Seamless stainless steel pipes can be made in both small diameter and large wall thicknesses, but their length is generally limited; welded stainless steel pipes can have relatively thinner walls, making them suitable for both large diameter and small wall thicknesses. Theoretically, the length of the welded stainless steel pipe can match the length of the coil. Generally speaking, thicker pipes are more suitable for seamless pipes, while thinner pipes are more suitable for welded stainless steel pipes.
2. Wall Thickness Uniformity and Concentricity: In terms of wall thickness uniformity and concentricity, welded stainless steel pipes are better than seamless stainless steel pipes. This is because the thickness tolerance of cold-rolled steel sheets is more uniform, resulting in more even deformation during the forming process.
3. Performance: Seamless pipe rolling is affected by factors such as equipment precision, resulting in uneven thickness and concentricity issues. However, its roundness is better than that of stainless steel welded pipe.
4. Performance: Stainless steel welded pipe has better uniformity, surface quality, expansion performance, bending, and end-forming performance. Cold-rolled sheets have better uniformity in performance than pipes, and stainless steel welded pipe typically uses online solution treatment, resulting in more uniform heat treatment and more stable performance. However, low-to-mid-range stainless steel welded pipes on the market today lack heat treatment processes, leading to significant quality differences. For seamless stainless steel pipes, samples taken from different locations on the same pipe show varying performance, sometimes significantly. During heat treatment, the bundled heat pipes of seamless pipes experience uneven heating and inconsistent cooling rates.
5. Price: Stainless steel welded pipe is cheaper and more environmentally friendly. Good welded pipe factories can achieve factory environments comparable to electronics factories; seamless pipe factories are often surrounded by oil and lubricants, and the pickling environment is particularly poor. Overall, seamless stainless steel pipe is more expensive than stainless steel welded pipe. However, it also has the following characteristics: seamless pipes are suitable for thick-walled pipes, while stainless steel welded pipes are more suitable for thin-walled pipes.
5. Pressure Bearing Capacity: Under the same specifications, stainless steel seamless pipes can withstand slightly higher pressures than stainless steel welded pipes.
6. Delivery Time: Stainless steel welded pipes are made by rolling stainless steel sheets, which is relatively simple to process, resulting in a shorter delivery time. Stainless steel seamless pipes require starting with round steel bars, piercing, and then undergoing multiple cold drawing/cold rolling processes, followed by solution annealing and pickling before the finished product is produced, resulting in a longer production cycle.
Post time: Apr-29-2026