Square pipe is a name of square pipe, that is, steel pipe with equal side length. It is made by rolling strip steel after technological treatment. Generally, strip steel is unpacked, flattened, curled and welded into a round tube, then rolled into a square tube and cut into pieces. The national construction industry standard "Square Rectangular Steel Pipe for Building Structure" is edited by Institute of Technology. High strength and high resistance. Its formability is equal to or better than Q345B, and its yield ratio meets the requirements of national building industry codes for earthquake resistance. . The largest specification of our rectangular steel pipe production line is 500mm*500mm* 19mm, ranking second in the world. . Its formability is equal to or better than Q345B, and its yield ratio meets the requirements of national building industry codes for earthquake resistance. . Using precision seamless steel tube to manufacture mechanical structure or hydraulic equipment can greatly save processing time and improve material utilization. The production process of straight welded pipe is simple, the production efficiency is high, the cost is low, and the laying is relatively dull. The strength of spiral welded pipe is generally higher than that of straight welded pipe. Square pipe is a name of square pipe, that is, steel pipe with equal side length. It is made by rolling strip steel after technological treatment. Generally, strip steel is unpacked, flattened, curled and welded into a round tube, then rolled into a square tube and cut into pieces. Square pipe is a name of square pipe, that is, steel pipe with equal side length. It is made by rolling strip steel after technological treatment. Generally, strip steel is unpacked, flattened, curled and welded into a round tube, then rolled into a square tube and cut into pieces. Then the round tube is rolled into a square tube by the forming unit, which is called "indirect square tube forming" process and adopts the traditional rolling and bending process. The method of processing circular welded pipe or seamless steel pipe into square, rectangular and other special-shaped pipes through roll cold bending and extrusion deformation. 4, the current national and industrial construction acceptance specifications, procedures, standards, as well as provincial and municipal regulations on construction management. Expansion joint socket should be against the direction of water flow. 5. The piping and bonding technology of drainage plastic pipes shall be implemented according to the following provisions: (1.