Study on the lubrication state evolution of rolling mill main drive shaft sliders under oil-gas lubrication

Purpose Under harsh operating conditions such as high temperature, heavy load and low speed, the sliding block of the rolling mill main drive shaft is prone to lubrication failure, leading to frictional heating and burn damage, even with the adoption of oil-gas lubrication systems, which seriously affects equipment safety and production efficiency. This paper aims to reveal the evolution mechanism of the lubrication state of the sliding block under oil-gas lubrication conditions and identify the key influencing factors. Design/methodology/approach A lubrication model of the rolling mill main drive shaft sliding block was established to simulate the distributions of oil film pressure, film thickness, friction stress and temperature on the slider surface, and to analyze the effects of factors such as radial clearance, deflection angle, oil content and load on the lubrication state thresholds of the sliding block. Findings The study indicates that the evolution of the lubrication state is affected by the coupling of multiple factors. Increasing the radial clearance or deflection angle weakens the load-carrying capacity of the oil film, triggers friction stress concentration and temperature rise, and accelerates lubrication failure. While increasing the oil content can effectively compensate for the aforementioned adverse effects, its effectiveness diminishes with the increase of structural parameters. Changes in the radial clearance and deflection angle not only affect the oil film thickness but also cause the migration of high-pressure and high-stress zones on the surface, thereby triggering localized heating and burn damage. Originality/value This study systematically reveals, for the first time, the lubrication state evolution and failure thresholds of rolling mill sliders under oil-gas lubrication in complex operating conditions, providing a theoretical basis for the structural optimization design and failure prediction of main drive shaft sliders.