Parameters of the Deformation Zone and Boundary Conditions of the Piercing Process

摘要

The quality and accuracy of pipes produced by modern pipe-rolling plants are mainly dependent on the quality of the shells produced by piercing mills. Therefore, in designing rolling tool, followed by setting up a piercing mill, it is necessary to ensure that shells produced are of high accuracy and quality. To this end, the effect of changes in the parameters of the deformation zone and the boundary conditions on the piercing process should be taken into account. The deformation zone of a piercing mill and its main sections are considered. The effect of change in each parameter on the dimensions of the resulting shell and on the controlled parameters of the piercing process is determined. The accuracy of shells depends on the capability of the roll design to ensure that the angle of the sizing portion of the plug corresponds to the angle of the exit cone of the roll, taking into account the distortion of its profile due to the turn through the feed and toe angles, and the quality depends on the capability to ensure the operation in the recommended ranges of controlled parameters of the piercing process. For hard-to-deform high-alloy steels, narrower ranges of controlled parameters are used. The effect of the type and design of the rolls of the piercing mill on the parameters of the deformation zone and the dimensions of the resulting shell is studied.