Types of Pipes
Pipes are classified into two groups: seamless pipes and welded pipes, based on the manufacturing method. Seamless pipes are formed in one step during rolling, but bent pipes require a welding process after rolling. Welded pipes can be classified into two types due to the shape of the joint: spiral welding and straight welding. Although there is debate as to whether seamless steel pipes are better than bent steel pipes, both seamless and welded pipe manufacturers can produce steel pipes with quality, reliability, and durability against highly corrosive. The primary focus should be on application specifications and cost aspects when determining the type of pipe.

Seamless Pipe
seamless pipe is usually manufactured in complex steps starting with hollow drilling from billet, cold drawing, and cold rolling process. To control the outside diameter and wall thickness, the dimensions of the seamless type are difficult to control compared with welded pipes, cold working improves mechanical properties and tolerances. The most important advantage of seamless pipes is that they can be manufactured with thick and heavy wall thicknesses. Because there are no weld seams, they can be considered to have better mechanical properties and corrosion resistance than welded pipes. In addition, seamless pipes will have better ovality or roundness. They are often best used in harsh environmental conditions such as high loads, high pressures, and highly corrosive conditions.

Welded Pipe
Welded steel pipe is formed by welding a rolled steel plate into a tubular shape using a joint or spiral joint. Depending on the external dimensions, wall thickness, and application, there are different ways of manufacturing welded pipes. Each method starts with a hot billet or flat strip, which is then made into tubes by stretching the hot billet, tying the edges together, and sealing them with a weld. Seamless pipes have tighter tolerances but thinner wall thicknesses than seamless pipes. Shorter delivery times and lower costs may also explain why bent pipes may be preferred over seamless pipes. However, because welds can be sensitive areas to crack propagation and lead to pipe breakage, the finish of the external and internal pipe surfaces must be controlled during production.