The welded square pipe is divided into
1. According to the process - arc welding square tube, resistance welding square tube (high frequency and low frequency), gas welding square tube and furnace welding square tube 2. According to the weld - straight welded square pipe and spiral welded square pipe.Material classification
Square tubes are divided into ordinary carbon steel square tubes and low alloy square tubes according to material. 1. Ordinary carbon steel is divided into Q195, Q215, Q235, SS400, 20# steel, 45# steel, etc. 2. Low alloy steels are divided into Q345, 16Mn, Q390, St52-3, etc. Production standard classification Square tubes are divided into national standard square tubes, Japanese standard square tubes, British standard square tubes, American standard square tubes, European standard square tubes and non-standard square tubes according to production standards.Section shape classification
Square pipes are classified according to section shape: 1. Simple section square tube: square tube, rectangular square tube. 2. Square tube with complex section: flower shaped square tube, open square tube, corrugated square tube and special-shaped square tube.Surface treatment classification
Square pipes are divided into hot-dip galvanized square pipes, electro galvanized square pipes, oiled square pipes and pickled square pipes according to surface treatment.Use classification
Square tubes are classified by purpose: square tubes for decoration, square tubes for machine tool equipment, square tubes for mechanical industry, square tubes for chemical industry, square tubes for steel structure, square tubes for shipbuilding, square tubes for automobile, square tubes for steel beams and columns, and square tubes for special purposes.
Wall thickness classification
Rectangular tubes are classified according to wall thickness: extra thick walled rectangular tubes, thick walled rectangular tubes and thin-walled rectangular tubes. 1. Process flow of sanitary mirror tube Pipe blank - Inspection - peeling - Inspection - heating - perforation - Pickling - grinding - Lubrication and air drying - welding head - cold drawing - solid solution treatment - Pickling - pickling and passivation - Inspection - cold rolling - degreasing - head cutting - air drying - internal polishing - External polishing - Inspection - Identification - finished product packaging 2. Industrial pipe process flow Pipe blank - Inspection - peeling - Inspection - heating - perforation - Pickling - grinding - Lubrication and air drying - welding head - cold drawing - solid solution treatment - Pickling - pickling passivation - Inspection 3. Welded pipe process flow Uncoiling - leveling - end shearing and welding - looper - forming - Welding - internal and external weld bead removal - pre correction - induction heat treatment - sizing and straightening - eddy current testing - cutting - hydraulic inspection - Pickling - final inspection - packaging 4. Process flow of seamless square pipe Round steel - tube blank - Inspection - heating - perforation - sizing - hot rolling - flat head - Inspection - Pickling - spherical annealing - cold drawing - forming - joint alignment - Inspection