Dependence of the level of residual stresses on the composition of coatings and conditions of electric arc metallization

Abstract

A modified method for determining the stresses that appear in electrically metallized coatings in the process of spraying followed by cooling is suggested. Using this method, we study the dependence of internal stresses on the efficiency of the spraying process, coating thickness, and powder wire charge composition. According to the results of these investigations, all the coatings under consideration can be classified into four groups. It is shown that the residual stresses in the coatings relax as a result of plastic deformation of low-strength structural components and/or as a result of crack initiation and growth in brittle components. Depending on the correlation between the plastic and brittle phases, one observes either a single crack or numerous cracks. The strength and crack-resisting characteristics of electrically metallized coatings can be improved significantly by optimizing the powder wire charge composition.