Abstract
This study investigates the thermal and mechanical processes occurring in the columns of the "United" (USA) hydraulic forging press with a force of 22.5 MN due to the influence of a heated workpiece. The focus is on the impact of non-uniform heating of the columns on the stress-strain state of the press elements, wear of its components, and the reduction in operational precision of the equipment. To analyze the thermal effects, a series of surface temperature measurements were conducted using the Thermo CAM P60 thermal imager, which provides high measurement accuracy. Experimental data confirm that the temperature distribution along the height and circumference of the columns is non-uniform, due to heat exchange between the workpiece and the press, as well as the surface condition of the columns (roughness, oxide films, and lubrication layers). The consequences of uneven heating include the formation of additional thermal stresses, misalignment of the crosshead, accelerated wear of guide bushings and hydraulic cylinder seals, as well as increased stresses in the "crosshead-column-nut" system. Over prolonged operation, these factors lead to a reduction in press rigidity, decreased forging accuracy, and a higher likelihood of failures in expensive press components. To investigate thermal processes, a scale model of the press, reduced by a factor of 30, was created. The model was used to study thermal deformations of the frame and the effect of eccentric placement of the workpiece on the uneven heating of the columns. The frame for dial-type indicators was thermally insulated to avoid temperature influence. The conclusion emphasizes the importance of a comprehensive approach to studying the operating conditions of column presses, including the use of finite element analysis and large-scale experiments on operational equipment.
Keywords:
hydraulic press, press columns, thermal impact, non-uniform heating, stress-strain state, component wear, forging accuracy, thermal stresses, crosshead misalignment, finite element modeling