Changsha Xiangjia Metal Materical Co., Ltd.

The production process of large-diameter  welded pipe  is can be divided into the 3 types: 1. Large-diameter spiral steel pipe is made by hot-rolled steel coils and welded by spiral coiling. Because it is spiral weld, so it also called spiral welded steel pipe.  2. Large-diameter straight seam steel pipes are coiled and welded with hot-rolled steel coils and medium-thick plates. Because there is one or two straight seams on pipe, so it also called straight seam steel pipes. The process is divided into two types: 1. double-sided submerged arc welding process, most are large-diameter thick-wall welded pipe. 2.  high-frequency welding process, mainly are small-diameter thin-wall welded pipes. 3. Large-diameter coiled pipe, using medium and thick plates as raw material, coiled with a pipe rolling machine, rounded, and then submerged arc welding process, because its welding shape is like a T-shape, it is also called a T-shaped welded pipe. Changsha Xiangjia Metal Materica...

 The main production process of  large-diameter welded pipe , Plate inspection: After the steel plate used to make large-diameter submerged arc welded pipe enters the production line, the whole plate is firstly inspected by ultrasonic; Edge milling: Double-sided milling is performed on both sides of the steel plate by a milling machine to make it reach the required plate width, plate edge parallelism and groove shape.  Pre-bending: Use a pre-bending machine to pre-bend the edge of the board so that the edge has a curvature that meets the requirements; Forming: On the JCO forming machine, one half of the pre-bent steel plate is stamped repeatedly and pressed into a "J" shape, and then the other half of the steel plate is bent into a "C" shape, finally forming an opening The "O" shape 5. Pre-welding: The formed longitudinally welded steel pipes are joined together and the gas maintenance welding (MAG) is selected for continuous welding. Internal welding: For...