Creation and Fundamental Characteristic of Super Deformation Joining Method

Abstract

The endless hot rolling concept was introduced to meet the demand for diverse hot-rolled steel sheet products produced by a cost-effective process compared with the conventional batch-type process. Endless rolling involves joining the head and tail ends of two bars following their rough rolling. By applying solid-state joining utilizing the high temperature of the joined materials for endless hot rolling, a new joining technology was proposed to instantaneously obtain a sound and uniform joint as the base metal using relatively simple equipment. This report presents the super deformation joining method, which was developed from a study on remedying the friction joining method. In this method overlapped materials are sheared incompletely to obtain a sound joint. In laboratory tests, in the presence of scale on the overlapping surface, the joint strength was approximately half that of the base metal, and the joint area was about 60 %, although the joint strength was approximately the same as that of the base metal when there was no surface scale. Obtaining a sound joint under actual hot rolling conditions, in the presence of scale on the overlapping surface remains a problem to be overcome.