Study on the rotary forming process of a rim-thickened disc-like part using a local heating method

Abstract

A local-heating rotary-forming process, which was similar to a rotary beading forming process, was developed to produce a rim-thickened disc-like part. A motion controlling model and a power controlling model based on a Gaussian-distributed flame heat source were established to provide references for deciding heat input. Via FE simulation, deformation rules including various field distributions were explored. It was found that local heating can result in large temperature gradients in the blank and introduce different flow stresses in different local sections. Compared with cold rotary forming processes designed for rim thickening, smaller but more uniform stress fields can be achieved by this new forming process. In addition, the required forming force is decreased, which is beneficial to the stable thickening of large-sized blanks. Furthermore, the influencing law of heating temperature during preheating and thickening on the forming quality was investigated. It was implied that the peak preheating temperature should be lower than 700 °C and the ideal heating temperature in the deformation forefront is around 950 °C. Experiments were carried out for verification, with a maximum rim thickening ratio of 2.6 achieved, which is much higher than those in cold rotary forming processes.