Corrosion-wear performance evaluation of 8Cr4Mo4V-bearing steel with pit-corroded defects considering fractal dimensions

Abstract In the field of tribology research, most of the problem-oriented methods for evaluating corrosion-wear interaction behavior are complex and time-consuming. The present work aims to establish the correlation between corroded surface characteristic parameters and corrosion-wear coupling damage of 8Cr4Mo4V-bearing steels, and an object-oriented strategy for corrosion-wear properties estimation is proposed. The alternating corrosion-wear behavior of 8Cr4Mo4V-bearing steel is investigated by integrating salt spray tests with tribological experiments in three types of corrosive conditions, considering the effects of industrial atmosphere and haze particles. The evolution of corroded surface morphologies is determined by image analysis combined with fractal theory, among which the fractal dimension of corrosion pits (FDCP) is calculated using a box-counting algorithm on binarized images after edge detection. The influence of corroded surfaces and atmospheric corrosion factors on friction and wear is studied. Results show that corrosion defects exhibit significant fractal features, the FDCP is depended on damage degree of corroded surfaces. Owing to the corrosion-crush effect, the wear resistance of 8Cr4Mo4V-bearing steels is decreased significantly. The FDCP exhibits a robust positive correlation with the corrosion ratio, whereas it demonstrates a weak correlation with tribological performance indicators. A damage coefficient of corrosion defect (DCCD) is proposed to evaluate the corrosion-wear performance of 8Cr4Mo4V-bearing steels, which take into account the coupling effect in corrosion defects and surface morphologies. These research findings significantly contribute to assessing and controlling the corrosion-wear properties of 8Cr4Mo4V-bearing steels in marine atmospheric environments.