Galvanized square steel pipes, rectangular steel pipes, and steel hollow profiles are collectively referred to as square pipes and rectangular pipes according to their section shapes. It is processed and rolled from strip steel. Generally, the strip steel is unpacked, flattened, coiled, and welded to form a round tube, and then the round tube is rolled into a square tube, and then cut into the required length. Square rectangular tube is also called cold-formed hollow section steel, referred to as square tube or rectangular tube.