Investigation of the process of forming geometric parameters of seamless pipes: analysis of the kinematic-force interaction on the extraction-calibration mill

In the production of seamless pipes, continuous-mill TPAs are currently the most common. One of the features of continuous rolling mills with a retained mandrel is the presence of an extraction and calibration mill (ICS). In the production of pipes on a continuous rolling mill, the final dimensions of the pipe are formed on the ICS, which ensures, in addition to the final stage of pipe deformation, that the pipe is also removed from the mandrel of the continuous rolling mill. During this operation, tension occurs between the mills, which affects the accuracy of the pipes produced. This is especially noticeable when forming the rear end of the whip, since after the whip leaves the last cage of the continuous mill, it comes into contact with the mandrel for some time, and the extraction and calibration mill creates tensile stresses, which leads to a section of local thinning of the pipe. The rejection of pipes for this defect can reach 8 % of the total production volume. Therefore, the search for new technical solutions.