Abstract
Abstract
The current paper reports the results of an experimental investigation into the effect of the circumferential loading on the quality of the billet cross-section and cropping time during a novel bar-cropping process. The new precision bar-cropping process technique uses a continuous circumferential strike on a metal bar with a pre-machined V-shaped notch. According to the relationship between loading mode and crack propagation, several different control curves of strike frequency versus time and stroke versus time were designed and applied in order to analyse how to improve the quality of the cropped billets and decrease the cropping time. The experimental results indicate that the ideal control mode is the combination of a linear decrement in the strike frequency—time curve and a linear increment in the stroke—time curve during the rotary strike cropping, by which higher cross-section quality and shorter cropping time may be achieved. Moreover, a new assessment method is proposed for the purpose of evaluating the cross-section of the cropped billet.