Effect of weld strength on pipe end deformation - improvement of roundness at the end of ERW pipes with thin wall IV

摘要

The deformation behavior of electric resistance welded (ERW) pipes resulting from a sizing process was investigated in detail using a 3-dimensional elastic-plastic finite element analysis and an experimental method. The purpose of the study was to establish the effect of welded strength on the deformation of the pipe end after the pipe was cut, which results in the deterioration of the roundness of pipe end. It was found that the extent of deformation to the pipe end, caused by the non-uniform distribution of strength in the circumferental direction, can be controlled by controlling the ratio of the top and bottom to side roll radius on a 4-roll sizer, with a vertical and horizontal roll stand having the same roll caliber as that when combined with a 2-roll sizer. It was also confirmed by calculations and experiments that the decrease of the top and bottom roll radius in the circumferential seam direction of a pipe, compared with that of the side roll radius on a 4-roll sizer, was greater resulting in the improvement of the roundness of the pipe end.