Welding matters of longitudinal welded steel pipe

Welding matters of longitudinally welded steel pipes are classified according to manufacturing methods. Steel pipes can be divided into two categories according to manufacturing methods: seamless spliced steel pipes and electric welded steel pipes. Electric welded steel pipes are divided into furnace welded pipes, arc welded (resistance welder) pipes and fully automatic arc welded pipes due to their different welding methods. They are divided into two types: straight seam welded pipes and spiral welded pipes. They are divided into ring-shaped pipes based on their top. Welded pipes and special-shaped (square, flat, etc.) welded pipes. Welding matters of longitudinally welded steel pipes are further divided into electric welded steel pipes for bottom pressure hydrodynamic transportation, spiral seam arc welded steel pipes, immediate coil welded steel pipes, and electric welded pipes. Seamless spliced steel pipes can be used as various liquid and vapor pipelines. According to materials, steel pipes can be divided into carbon pipes, alloy pipes, stainless steel pipes, etc. according to the pipe material (ie alloy structural steel). Alloy tubes can be divided into: low alloy tubes, aluminum alloy structural tubes, high alloy tubes, and high toughness tubes. Rolling bearing tube, high temperature and acid resistant stainless steel tube, precision alloy (such as Kovar aluminum alloy) tube and its high temperature alloy tube, etc. According to the interface method, the steel pipe can be divided into: smooth pipe (pipe end without thread) and threaded pipe (pipe end contains thread) according to the pipe end connection method. The wire tube is divided into: ordinary wire tube and tube end thickened wire tube. Thickened wire tube can also be divided into: outer thickened type (with external thread), internal thickened type (with internal thread) and internal and external thickened type (with internal and external threads) and other types of wire tube. According to the thread form, the threaded tube can also be divided into: general cylindrical or cone thread and unique thread and other threaded tubes.