Technology of restoration of cylindrical and screw surfaces of the conveyor by plasma spraying of coatings

In conditions of serious workload of domestic enterprises, especially repair and restoration centers and workshops, improving the process of various machines and technologies for their restoration becomes a particularly important task. Thus, at the present stage, the creation of new technologies that provide high-quality restoration of worn surfaces of parts, as well as the creation of composite coatings with the necessary performance properties, is of particular relevance. From an economic point of view, this issue is very acute within the framework of the state import substitution program, since, as practice shows, the service life of restored machine parts reaches the level of new ones, while the cost of such parts is several times lower. The paper presents the results of research aimed at obtaining technological modes of plasma spraying for both helical and cylindrical surfaces of a part (screw) during its restoration. A correlation analysis of the obtained data on the effect of spraying modes on coating adhesion was carried out in order to identify multicollinear relationships. A regression analysis was also carried out, as a result of which equations were obtained that describe the effect of spraying modes on the adhesion of the coating. A graphical interpretation of the obtained dependencies in the form of desirability functions is presented, which made it possible to evaluate the nature and degree of influence of spraying modes on the adhesion values of the resulting coating. In addition, using existing software systems, ranges of uniform technological modes for spraying the working surfaces of the screw were obtained. The hardness and wear resistance of the coating were measured. The results of the study allow us to recommend technological modes with the prescribed composition of the spraying material for restoring worn surfaces of the screws of transport conveyors, which are very actively used in aircraft and mechanical engineering.