Increase of abrasive wear resistance of parts by means of variation of welding technique of double-layer coatings with hard surface

Abstract

The double-layer welding applied for restoration of parts of construction, road and tillage machinery allows to create a coating that resists shock loading and prevents abrasive wear. It is determined by significant differences between the properties of the lower layer that is relatively soft and the upper hard layer. Known researches of this method do not consider the influence of welding technology on the wear resistance of obtained coating in an environment with high content of abrasive inclusions. The aim of the paper is to determine the degree of influence of technological methods of double-layer coatings formation on the wear of parts used in soil medium. The welding was carried out manually during restoration of ploughshares with ray-shaped wear according to four variants of technology. The wear was controlled by weight loss. Experiments reveal that the wear in function of operating time is in straight-line dependence for all technology variants. Operating time before reaching the steady state mode of wear and the limit state depends on welding technique. The influence of methods of coating formation technology on abrasive wear resistance that is due to the difference of thermal influences on weld metal is considered. The optimal technology variant for maximum wear resistance of coating is cooling of each bead by applying both first and second layers. The implementation of such welding technology allows to increase the abrasive wear resistance by 30% in comparison with other methods. The use of double-layer welding technology increases the resource of restored ploughshare by two times in comparison with a factory-made one.