Steel pipes can be divided into two main categories based on their production methods: seamless steel pipes and welded steel pipes, with the latter commonly referred to as ERW pipes.

Seamless steel tubes can be categorized by their production methods, including hot-rolled seamless tubes, cold drawn tubes, precision steel tubes, hot expanded tubes, cold spinning tubes, and extruded tubes, among others.

Seamless steel tubes are made from carbon or alloy steel, and are available in hot-rolled or cold-rolled (drawn) varieties.

2. Welded steel pipes are categorized based on their welding techniques into furnace-welded pipes, electric-welded (resistance-welded) pipes, and automatic arc-welded pipes. They are further divided into two types of welding forms: straight seam welded pipes and spiral seam welded pipes. Additionally, they are classified by their end shapes into round welded pipes and non-standard (square, flat, etc.) welded pipes.

Welded steel pipes are made by welding steel plates rolled into tubes, either in a longitudinal or spiral seam. In terms of manufacturing methods, they are categorized into low-pressure fluid transmission pipes, spiral seam electric welded pipes, direct roll welding pipes, and electric welded pipes, among others. Seamless steel pipes are suitable for liquid and gas pressure pipelines in various industries. Welded pipes are used for water supply pipelines, gas pipelines, heating pipelines, electrical pipelines, and more.