Hydraulic screwdown control system for mandrel mill

A process for producing small-diameter seamless steel tubes using a mandrel mill line is described. The general concept of end-thinning control and the configuration of a hydraulic screwdown control system, including the application of an expert system are discussed. To improve cylinder response and stabilization of the servo control in the system, the velocity, feedforward, compensation, cylinder position offset compensation, and hydraulic pressure feedback compensation functions were applied. The static adaptive function and dynamic adaptive function of screwdown start time were also applied to the system, since screwdown start timing control is important in precisely forming the thin tapered tube ends.<
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