Thermomechanical Treatment of Long Low-Stiffness Shafts

摘要

The following paper describes the method for heat straightening of long low-stiffness shafts in a thermomechanical treatment tool. The straightening tool with a fixed workpiece, whose coefficient of thermal expansion is lower than that of the shaft material, is subjected to cooling. As a result of the difference of coefficients of thermal expansion at cooling axial loading occurs, causing axial the straightening of the shaft. Subsequent sections described the control system for automatic thermomechanical treatment and the mathematical model of the controlled system, functionally combining the input and output parameters. The paper also presents the experimental part of the study, within which the thermomechanical treatment tool was employed to perform axial straightening of shafts combined with hardening (aimed to increase the corrosion resistance of steel). The conducted tests showed that during heating the shaft deforms at the expected speed, in accordance with the heat treatment technology. As a result, the experimental tests have confirmed the validity of the developed models, diagrams and analytical dependencies.