Process for manufacturing rectangular box pipe

The invention discloses a process for manufacturing a rectangular box pipe. The process comprises the following steps of: 10, preparing a web, side plates, liners and process separating plates; 20, assembling the web and the liners in a superposed mode; 30, arranging the side plates and the process separating plates; 40, arranging a cover plate; 50, fixing the side plates, the cover plate and a bottom plate; and 60, grinding a main weld joint. By the process for manufacturing the rectangular box pipe, the side plates and the web are welded by the liners, so that welding current is reduced, the welding sequence of the side plates, the web and the process separating plates is reasonable, the whole body is divided into a plurality of parts, the complicated process is changed into the simple process, the accuracy of a single body is improved, and the accuracy of the whole rectangular box pipe is ensured. In addition, a plurality of process separating plates are arranged in the rectangular box pipe along the lengt