Several metal flow joining methods have been developed since 1980 aimed at low cost and high productivity. In this study, we examine a new metal flow joining method that enables a shaft and ring to be combined without the need for any specialized punch. In this experimental study, 20-mm-diameter solid shafts and 40-mm-outer-diameter rings having a 20-mm-inner-diameter step at the 18.5-mm-inner-diameter center hole were used. The material combinations of the shaft/ring were S45C/SKD11, A5056/S45C, and S45C/A5056. The experiment was performed as follows. The shaft was inserted into the ring and pressed. Then, metal flowed between the contact faces. The gap between them was filled with the flowing metal, and then, they were joined by the high clamping pressure. The primary results were as follows. This joining method caused small amounts of metal flow because of the highly precise fitting between the shaft and ring. Therefore, they could be joined by small pressing strokes. In this experiment, the maximum joining efficiency (shaft return proof load/joining load) ranged from 25% to 35%. This new metal flow joining method appears to be highly useful in terms of low cost, high productivity, and non-mass production.
