Intelligent Control System of Internal Expansion over Bending and Calibration (IEOBC) Process for Large Pipe Ends

The flattening and asymmetry of a pipe end section seriously affects the welding quality between pipes, therefore the calibration process for pipe end to improve roundness is essential. Because the calibration for a pipe end involves local elastic-plastic deformation for the end effect, it is still difficult to establish an accurate theoretical model. The reasonable and intelligent control method is nevertheless an effective means to improve the production efficiency. In this paper, an internal expansion over bending and calibration (IEOBC) process is introduced. According to the characteristics of the process, the structure of the mobile intelligent calibration machine for large pipe ends is designed, and the intelligent control hardware system of the machine is built. Based on the LabVIEW software platform, an intelligent control software system for the IEOBC process is developed. A three-step control strategy is combined with pipe size detection and ovality recognition. The intelligent prediction and execution of the calibration process parameters are realized. The experimental results show that the intelligent control system has good stability and accuracy, and the ovality can be controlled within 0.5%.