Analysis of Metal Flow and Deformation Features during Continuous Tube Rolling Process with Mandrel Mill

Abstract

With the aid of commercial FE code MSC.SuperForm, the structural steel tube continuous rolling process of a typical hollow tube specification 152.5×12.5mm is simulated based on Bao Steel 152.5 main pass sequence of 140mm 8-stand mandrel mill, and the distribution characteristics of stress/strain, outline lateral spread, temperature changes of workpiece in continuous rolling process and distribution of stress/strain, friction of workpiece in deformation zone are analyzed. Analysis results indicate that deformation of workpiece along the width of the groove, especially at the top and the bottom of the groove is highly inhomogeneous due to the unequal draught and the longitudinal stress of special position (the top and the bottom of the groove) of workpiece is always an alternate state, in a tensile-compressive-tensile manner, and has a distinct rule. In the first stand, outline dimension of workpiece gradually increases during reducing process and early stage of wall thickness reduction, but it gradually decreases during middle-late stage of wall thickness reduction and tends towards stability at last. It is inhomogeneous that distribution of unit compressive stress and longitudinal strain of workpiece in deformation zone, and contact stress and total equivalent plastic strain are maximal in inner surface of workpiece contacting with mandrel. Temperature difference between the outer and the inner surfaces of workpiece is obvious.

Research on the impact of mandrels in titanium tubes during tube continuous rolling

“…Zhou [12] has conducted a study on the influence of mandrel limiting speed on the size accuracy of hollow shell and axial force of the mandrel. Yin et al [13] have employed a three-dimensional elastic-plastic thermal coupled finite element method to obtain the impact of mandrel velocity and friction coefficient on the force-energy parameters and deformation parameters during rolling. Zhao et al [14] have calculated the friction coefficient between the rolled piece and the mandrel in a Fully-floating mandrel mill and observed that this coefficient displayed a rising trend along the rolling direction.…”