Seamless pipe vs Welded pipe: Which one is more expensive?
Generally speaking, the price of seamless pipes & tubing is higher than that of welded pipes. The main reasons why the price of seamless pipes is higher than that of welded pipes are as follows:
1. Manufacturing process
Seamless pipes are made by directly heating steel billets to a certain temperature and processing them through processes such as perforation, plugging, and hot rolling. They have no welds and are a homogeneous steel pipe. Because the material has no seams or welds, it has high strength and corrosion resistance, and has a wider range of applications, such as petroleum, chemicals, natural gas, ships, construction and other fields.
Welded pipe is a steel pipe made from a pipe blank pressed from a steel plate or steel strip, which is made through multiple processes of bending, welding and cutting. The production process of welded pipes is simple, the production efficiency is high, there are many varieties and specifications, the equipment investment is small, and the price is cheap. Because of its relatively low cost, it is widely used in construction, machinery, aviation and other fields. However, welding will change the grain structure and mechanical properties of the steel, making the strength and corrosion resistance of the welded pipe lower.
Seamless steel pipes are manufactured through a special process, and the raw material of seamless pipes is round steel. Good round steel, especially tube blank steel, has less impurities and good forging effect, so the yield will naturally be higher. Seamless steel pipes are formed in one step during the rolling process. The processing of seamless steel pipes has been changed from solid round steel to hollow round steel. During the piercing process, cutting and high temperatures are required. Wastewater and slag need to be treated during the pickling process. Natural gas, etc. are used in the annealing process, and each process requires post-processing, which also consumes a lot of money. In addition, seamless tubes have a greater eccentricity due to process reasons, which, depending on the application of the tube, must be reworked by expensive grinding.
2. Quality requirements
The quality requirements of seamless steel pipes are relatively high, and the processing accuracy requirements are strict. It is necessary to ensure that there are no internal defects, the appearance is smooth, and there are no burrs. However, due to the limitations of the production method, it is difficult to avoid defects such as cracks and pores in the welded parts of welded steel pipes. High-quality seamless steel pipes require higher raw material and precision processing costs, and the price is correspondingly higher.
3. Service life
The material of seamless steel pipes is more uniform and dense, and its compressive and tensile strength indicators are higher than those of welded pipes, so its service life is longer and more stable.
4. Market demand
The market demand for seamless steel pipes is relatively small, and it is mainly used in fields such as petroleum, machinery, aviation, chemical industry, etc. that have high requirements on material quality. Welded pipes have a large market demand and are mainly used in construction, energy, transportation and other related fields. Therefore, for general occasions, the price of welded pipes is more affordable, and for some special fields, seamless steel pipes have become an indispensable and important material.
Conclusion:
This article analyzes the price difference between seamless steel pipes and welded steel pipes from three aspects: production process, quality requirements, service life and market demand. Overall, the price of seamless steel pipes is more expensive than welded steel pipes. Because the production process and quality requirements of seamless steel pipes are higher, and the market demand is also more specialized. But this does not mean that welded steel pipes are cheaper in all cases, and they need to be considered comprehensively based on specific circumstances. When purchasing steel pipes, you need to choose based on specific circumstances. Not only should you consider price factors, but also many aspects such as applicability, quality, and usage.
Additional content:
Technological development:
Modern inspection technology has found that there are edge deviations, pores and scratches on the surface and welds of welded pipes. Therefore, the quality of welded pipes is not inferior to seamless pipes. Therefore, the most advanced methods are used to weld steel pipes, and the quality is the same as seamless pipes. For the sake of completeness, final heat treatment should usually be factored into the price. Nonetheless, welded pipes will maintain their price advantage.
Read more: Seamless vs Welded Pipe
