| At present,the demand for energy is becoming stronger and stronger,and the way of pipeline transportation of energy has become an important way of energy transportation,so the manufacturing process of large-scale pipeline which is closely related with it has also been rapidly developed.In the pipeline manufacturing process,JCO and UO forming process are two main methods.Different from the traditional three-point bending JCO forming process,scholars have introduced a new four-point bending JCO forming process.The four-point bending JCO forming process has more significant advantages in cost and efficiency,fewer molds,adjustable process parameters and higher degree of flexibility.With the rapid development of computer technology,the application of computer aided process planning(CAPP)in manufacturing is becoming more and more important.Through the research of four-point bending JCO forming technology,the establishment of a CAPP system for the four-point bending JCO forming process design of X80 straight seam welded pipe can greatly improve the production efficiency of enterprises.Based on the existing research of four-point bending JCO forming process,this paper takes X80 pipeline steel as the research object and studies the planning method of determining important forming process parameters,such as minimum forming pass and upper and lower die fillet radius,by using the relationship between the limit span and relative error in the four-point bending JCO forming process of high-strength thick-wall steel pipe through a large number of numerical simulations.The prediction formula of fillet radius of upper and lower die is given,and all forming process parameters can be determined.In this paper,the prediction method of process parameters is integrated into the CAPP system,and all the forming process parameters can be calculated and planned by giving a specification of X80 tube blank.By adding the method of feedback adjustment of the lower pressure,the data of the upper die from the contact surface to the maximum lower pressure can be reflected more accurately,so that the lower pressure of each pass is more accurate.X80 large straight seam welded pipe commonly used in actual production was used for research.This paper carried out the simulation of X80 four-point bending JCO forming full circle with different specifications,redesigned the upper die,and did not carry out size proportional reduction.Two experiments of Φ508×8mm four-point bending JCO forming were completed,so as to restore the real production situation as far as possible.The simulation and experimental results are in line with the requirements,which verifies the feasibility of X80 high-strength steel to produce four-point bending JCO forming process,verifies the accuracy and feasibility of simulation calculation and CAPP system to predict the process parameters,and provides a reference for the actual X80 large-scale straight seam welded pipe production enterprises,so it has certain practical application value. |
