First of all, the materials are different

1. Welded steel pipe: Welded steel pipe refers to the steel pipe with joints on the surface after the steel strip or steel plate is bent and deformed into a round or square shape, and the blank used for welded steel pipe is steel plate or steel strip.

2. Seamless steel pipe: A seamless steel pipe made of a whole piece of metal is called a seamless steel pipe.

Second, the classification is different.

1. Welded steel pipe: According to different welding methods, it can be divided into arc welded pipe, high-frequency or low-frequency resistance welded pipe, gas welded pipe, furnace welded pipe and Bundy pipe. According to the purpose, it can be divided into ordinary welded pipes, galvanized welded pipes, oxygen-blown welded pipes, silk sleeves, metric welded pipes, idler pipes, deep well pump pipes, automobile pipes, transformer pipes, welded thin-walled pipes, welded special-shaped pipes and spiral welded pipes.

2. Seamless steel pipes: Seamless steel pipes are divided into heat pipes, cold-rolled pipes, cold-drawn pipes, extruded pipes and pipe jacking. According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special-shaped. Special-shaped tubes have many complex shapes, such as square, oval, triangle, hexagon, melon seeds, star and finned tubes. The maximum diameter is 650mm, and the minimum diameter is 0.3 mm According to different purposes, there are thick-walled pipes and thin-walled pipes.

Extended data:

use

Seamless steel pipes are widely used. Universal seamless steel pipe is rolled from ordinary carbon structural steel, low alloy structural steel or alloy structural steel, with the largest output, and is mainly used as pipes or structural parts for conveying fluids.

Seamless steel pipe has a hollow cross section and is widely used as a pipeline for conveying fluids (such as oil, natural gas, gas, water and some solid materials). Compared with solid steel such as round steel, steel pipe is lighter in weight under the same bending and torsion strength, and it is an economical cross-section steel.

It is widely used to manufacture structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames and steel scaffolding for construction. It can improve the utilization rate of materials, simplify the manufacturing process, save materials and processing time, and has been widely used to manufacture steel pipes.

Baidu encyclopedia-seamless steel tube