Restoring scraped surfaces of shaft and bearing in interference fit joints by hard chromium plating

Interference fitting widely used in the industry for connecting shafts and bushes. These type of joints are widely used as support of bearing machine parts. Rrepeated disassembling of shaft and bush interference fit, performed to repair and maintenance of machine parts, may cause serious damage to surface of joint parts depending on the roughness and surface quality of contact surface of joint parts. Bushes are usually expendable parts, but the shaft parts are long integrated and complex parts which supports other components of machine. So providing a way to repair the shaft surface can be considered crucial and leads to restoration of damaged shaft and reduced costs. In this study, we have investigated the effect of interference surface roughness on strength, friction coefficient of the contact surface and surface damage of interference fit joints during the disassembling procedure. Finite element and experimental analysis were performed to estimate friction coefficient in contact surface of joint parts. Also, magnified pictures of contact surfaces were applied, to evaluate the extent of damage in contact surface after disassembling of joints parts. Hard chromium plating was proposed to repair the shaft surface and the effect of hard chromium plating on strength of shaft and bush joints were measured experimentally. The results confirm successful use of hard chrome plating in repairing the shaft surface so that the strength of restored shaft joints were equal and in some instances even more than the initial joints.