As a manufacturer of square pipe, we should have a good command of each process and material properties of square pipe. When customers order welded pipe, square pipe and rectangular pipe are the customers'choices. We have repeatedly mentioned the advantages and disadvantages of square pipe and rectangular pipe, square pipe in the production process only the pipe end size is the most stringent, after all, square pipe is different from rectangular pipe, so in the production of square pipe, we should pay attention to the caliber and pipe end to do the best, so as to facilitate the installation and welding process can be convenient and fast construction. For the production of large diameter steel pipe with thinner wall thickness, attention should be paid to strengthening or bracketing steel pipe to prevent ellipse or caliber deformation of square pipe during transportation. For square pipe, the exact size of the caliber is the most important. Next, we should pay attention to the square pipe weld without undercutting. We should align the two weld edges of the rolled steel pipe, so that the welded steel pipe can be beautiful and standard. Secondly, attention should be paid to the straightness of square pipes. The straightness of square pipes not only affects the overall appearance of square pipes, but also affects the later construction welding.