Material retesting → vacuum hanging → board probe → flap → planing curl before demi plate (J molding) on the board edge → loose → enter demi steel plate (C molding) demi steel plate → curl → loose out → bend → pre-welded → welding cited the (quenching) arc board → welding → Qing root weld → mechanical repair end to cited hydrostatic test (put out) arc the board → ultrasonic inspection → mechanical expanding → tube ends of ultrasonic testing ring the stratification test to the UT → X-ray inspection → Magnetic particle inspection of the finished product inspection → weighing and measuring the length → outer anticorrosion → internal corrosion → mark → delivery.
The JCOE manufacturing technology is a welded pipe forming process developed in the 1990s, during the molding process, it is the first steel plate edge milling preflex by longitudinal edges (or planing), and then type J → C → O the order of the type of molding, in each step stamping expressed in three-point bending as the basic principle. Pass progressive molding, it is necessary to solve the following problem: how to determine the shape of the mold, the upper die stroke mode spacing, and how many times in order to ensure optimum bending radius stamping out the best opening gross round tube. These problems with the steel plate material, the specific mechanical properties of the steel production plant, pipe size (diameter and thickness), which makes it very complicated. Mainly by "trial and error" that whenever the replacement of new specifications or new steel grades, he took a certain number of sample pressure test, worked out the right amount of stamping. The trial and error method is more reliable, but the efficiency is relatively low. More process parameters, only through trial and error trouble. In order to obtain a mature technology, and even take months of trial and error process. The shape and spacing of the fixed lower mold and the trial and error process is often used only explore the punch stroke, so that the results obtained may not be optimal, not fully the capacity of the unit. So it is necessary to systematically study forming factors create a theory or formula, with the trial-and-error experience to develop the molding process, thereby eliminating the need or less need to experiment to reduce the cost and time of trial, and improve production efficiency.