Evaluation of Application for Hot-Bar Joining of Super Deformation Joining Method

The endless hot rolling concept was introduced to meet 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 a relatively simple equipment. This report presents type I super deformation joining that obtains a sound joint by incompletely shearing the overlapped materials. In laboratory tests, in the presence of a scale of 14 ∼ 24 μm thickness on the overlapping surface, the joint strength of the center of the joint area was approximately the same as that of the base metal, although reduction of area was smaller than that in the base metal. Obtaining a good joint shape with a small step around the joint area and evaluating the joint properties of wider plates remain as problems to be overcome.