From Free Moving to Controlled Flying—Evolution of Mandrel Moving Mechanism of Mandrel Pipe Mill over the Past 50 Years

The evolution of mandrel moving mechanism in mandrel pipe mill over the past 50 years is presented in chronological order according to mill startup time.Briefly described are the characteristics and shortcomings of different mandrel moving mechanisms from floating mandrel to retained mandrel.The reason of using rack in mandrel moving control is estimated.It is expected that the progress of new science and technology will open up new opportunities for the development of China's seamless steel pipe production technology.