The flower pattern and rolls design for ERW pipes with the different specification in the flexible roll forming process

摘要

To produce electrical resistance welding (ERW) pipes with the different specification efficiently and economically, flexible roll forming technology is urgently required. Based on the elastic plasticity deformation theory, combined with the basic parameters of typical roll forming units, the 3D finite element analysis (FEA)models of ERW pipes with seven kinds of sizes were built and the numerical simulations were conducted with the professional roll forming software COPRA. The mechanics law between strip and rolls in conventional roll forming was revealed and the results were obtained that the edge arc segment of rolls plays a major role and the straight segment restricts the deformation of strip in the W-shaped forming process. Considered the mechanics law and forming mechanism, the modular and compact design of flower pattern and rolls in first to fifth stands were conducted; a set of involute-tangent-arc roll profile for flexible roll forming of ERW pipes with seven kinds of sizes in first to fifth stands was proposed and verified with the numerical simulations. Results showed that the final product with the flexible design of flower pattern and rolls satisfied the accuracy requirement and the transverse strain distribution was optimized during the roll forming. The flexible roll forming technology reduces the time and costs for the preparation and replacement of rolls in first to fifth stands when ERW pipes with the different specification are produced, and the total weight of rolls is reduced by about 35%, realizing the lightweight production, which provides a novel method for the flexible roll forming of ERW pipes.