Parametric investigation on the surface defect occurrence in CONFORM process by the finite element method

It is widely known that the CONFORM process can produce ultra-long seamless products of complicated section-shapes without the need for pre-heating, but it may lead to products with a defect due to surface separation unless the process parameters are appropriately combined. Even though theoretical and experimental studies on the process itself have been intensively carried out, the study on the surface defect phenomenon is still in need of further study. In this paper, the authors address a parametric investigation on the occurrence of the surface defect in this process. Because several parameters are associated with the process, one has to parametrically analyze such a phenomenon. Here, the wheel velocity, the extrusion ratio, the abutment height, the friction coefficient and the flash-gap size are taken as parameters, and numerous parametric numerical experiments are carried out in order to analyze their effects on the surface defect occurrence.