Study On Progressive Forming Theory And Application

Along with the rapid development of construction of transport pipe-lines in our country, the demands for welded big-diameter pipes become greater and greater. It is in dire need of a set of theory to guide the production of pipes in China at present.The thesis first of all gives a systematic introduction and evaluation on the present situation of welded big- diameter pipes. Then starting with the theory of plastic deformation of plates, the thesis describes the bending process of open-seam pipes theoretically by applying the mathematical analysis method on the basis of the reasonable presumption and simplification of bending process. It analyzes and studies the deformation mechanism of plates under three deformation modes during the bending process and mainly reveals the internal relationship among the bending force, bending radius and angle during the process. Basing on the theory of single forming , the mathematical model of progressive forming of open-seam pipes is established. The preliminary process plan of bending open-seam pipes is generated through programming. The discussion centers on the effects on pipes quality and productivity by various process factor such as bending force, punch width, die gap and bending times etc. The reasonable final process plan is eventually generated by further comprehensive evaluation of the initial plan and combining the practical production.Through the systematic study of progressive Forming of the open-seam pipes, it offers important theory reference to the selection of bending equipment, the design of tooling and the decision of process plan etc. What's more , it is of significant value of engineering application.