Opening Research On O-forming Process Of Large Diameter UOE Pipe

UOE forming process is a set of pre-bending forming, U forming, O forming andwelding process in a multi-step forming method. Between each step and the previous stepare closely linked, the finished source of the previous step is the dough of the latter step,the open steel pipe after O forming is ready for welding process. The opening amount istoo large, is not conducive to welding, the opening amount is too small, is not conducivefor welding slag to discharge. In order to facilitate the conduct of the welding process, itrequires a certain amount of steel pipe opening. But in the actual production, the openingamount of steel pipe after O forming is difficult to control, whether we can achieve thewelding opening quantity required, is a problem to be resolved.In this paper, MSC.MARC of the finite element analysis software is used to simulateO forming process of UOE pipe. The formation mechanism of the opening of O formingwas revealed from the radius distribution of the inside and outside and middle layer ofsteel pipe, the circumferential strain distribution and the circumferential stress distribution.Because of the different springback situations and the different amount of springback atdifferent positions of the plate, the molded steel pipe has a certain amount of opening,which is the fundamental reason of the opening.The influence factors of the opening amount of steel pipe after O forming wereobtained, through the simulation of the different forming schemes of UOE welded pipeand O forming process. They are the sheet shape before O forming, the compression ratio,the baffle size of the forming upper mold, O the molding die radius of O forming and thesheet thickness. The influence law of these factors was studied, and the conclusion wasobtained that the compression ratio is the main factors influencing the opening amount ofO forming.The Influence of the compression ratio and the baffle size of the forming upper moldand the sheet thickness on the opening of O forming were obtained, through theexperimental study of U forming and O forming, compared with simulation results.