Optimization of groove shape in plugless rolling

The paper substantiates the relevance of conducting research aimed at optimizing the groove shape during continuous plugless rolling of pipes, which is an important task of improving the quality of pipe products. Special attention is paid to the problem of rational choice of the geometric configuration of the groove in order to reduce both the longitudinal and transverse wall thickness deviation of the pipe. To quantify the quality of rolled products, a generalized optimality criterion is proposed, based on the combined consideration of the levels of longitudinal and transverse wall thickness deviation. As part of the study, a system of restrictions on the control parameters of the process was developed, for which the eccentricity and the angle of groove taper were selected, with a fixed roll gap. The optimization was performed using computer modeling in the QForm software package. A sequential search for optimal parameter values was carried out using the gradient method based on a complete factorial experiment. The results showed that the proposed optimal roll pass design reduces the generalized wall thickness deviation by 10 % compared to the current industrial groove shape, and also contributes to a more uniform distribution of wall thickness both along the length of the roll and along the circumference of the pipe crosssection. Thus, the application of the developed approach makes it possible to increase the stability of the technological process and improve the quality of finished products without conducting industrial experiments. The results can be directly used in the development of new groove systems for continuous rolling mills.