1. Steel pipes can be divided into two categories according to production methods: seamless steel pipes and seam steel pipes. Seam steel pipes are referred to as straight seam steel pipes for short.
According to production methods, seamless steel pipes can be divided into: hot-rolled seamless pipes, cold drawn pipes, precision steel pipes, hot expanded pipes, cold spinning pipes, and extruded pipes. Seamless steel pipes are made of high-quality carbon steel or alloy steel, and are divided into hot-rolled and cold-rolled (drawn). The main feature of seamless steel pipe is that it has no welded seam and can withstand greater pressure. The product can be very rough cast or cold drawn parts.
Welded steel pipes are divided into furnace welded pipes, electric resistance welded (resistance welded) pipes and automatic arc welded pipes due to their different welding processes. Due to their different welding forms, they are divided into two types: straight seam welded pipes and spiral welded pipes. Because of their end shapes, they are divided into round Shaped welded pipe and special-shaped (square, flat, etc.) welded pipe. Welded steel pipes are formed by welding steel plates rolled into a tube shape with butt seams or spiral seams. In terms of manufacturing methods, they are divided into welded steel pipes for low-pressure fluid transportation, spiral seam electric welded steel pipes, direct coil welded steel pipes, and electric welded pipes. Seamless steel pipes can be used for liquid pressure pipes and gas pipes in various industries. Welded pipelines can be used for water pipelines, gas pipelines, heating pipelines, electrical pipelines, etc.
2. Precision steel pipe is a product that has appeared in recent years, mainly because the inner hole and outer wall dimensions have strict tolerances and roughness. Precision steel pipe is a high-precision steel pipe material processed by cold drawing or hot rolling. Because the inner and outer walls of precision steel pipes have no oxide layer, high pressure without leakage, high precision, high smoothness, cold bending without deformation, flaring, flattening and no cracks, they are mainly used to produce pneumatic or hydraulic components, such as cylinders or Cylinder.