Design and Research of Plug Bar Pre-rotating Device for Large Piercing Mill

The plug bar pre-rotating device is used to provide start-up torque to the plug bar of the piercer at such a moment when the billet is just fed into the pass and got contacting with the plug. Based on the operation experience of the piercer,the necessity of attaching the said pre-rotating device to the large piercing mill is identified. The calculation method as used for design of the device is described here in the paper. It is concluded that the plug bar prerotating device plays a very critical role for enhancing rigidity of the plug bar,improving the biting and piercing process conditions of the billet as well as bettering the shell quality.