Technological method for machining square and rectangular pipes

The invention provides a technological method for machining square and rectangular pipes. The technological method aims at solving the technical problem that large-caliber square and rectangular pipes are high in production cost in the prior art. The technological method mainly includes the steps of feeding, pressure forming, welding and finishing. By the adoption of the technological method for machining the square and rectangular pipes, a cold pressing method is adopted, raw materials are hot-rolled steel plates, the hot-rolled steel plates are pressed through a pressure forming machine, the thick steel plates can be pressed, equipment does not need to wrap products, the machining caliber and thickness are not limited by the size of the forming machine, the square pipes with the wall thickness ranging from 30 mm to 50 mm and the caliber ranging from 400 mm * 400 mm to 1100 mm * 1100 mm and the rectangular pipes with the length of the short sides larger than 400 mm can be produced, production cost is low, submerged arc internal and external welding is used for welding connectors, and product quality is reliable.