Xrbndy determining elasticity and residual stresses in plasma coatings

Currently, a strategically important task of technological independence of Russian industries is the restoration of wornout machine parts and equipment by the plasma method based on the use of coatings for various functional purposes. (Re-search purpose) The research purpose is studying the effect of plasma surfacing modes and surfacing materials on the fatigue resistance of restored parts and establishing the elasticity characteristics arising in coatings applied by plasma methods, as well as residual stresses in the fusion zone (Materials and methods) Samples for experimental studies were made of steel 40G. Plasma surfacing of coatings was performed with a composition of powdered material. The hardness of the samples with coatings was studied by nondestructive expressive measurement on a universal programmable electronic portable hardness meter. To optimize the parameters of plasma surfacing, the method of a complete factor experiment was used. Young's modulus was used as an optimization criterion. Experimental studies of elasticity characteristics in coatings applied by plasma methods were carried out according to generally accepted methods, taking into account the resonant frequency of bending vibrations of samples. (Results and discussion) In the surface layers of the deposited coatings, the elastic modulus has reduced values, and tensile stresses occur that reduce fatigue resistance by 20-25 percent from the level of extremely worn parts. The addition of 8 percent of aluminum powder to the initial powder hard alloys contributes to their wear resistance. A rational range of plasma coating modes has been determined from the point of view of obtaining high elastic properties of plasma coatings as a key stage of resourcesaving technology for restoring worn parts of technological equipment. (Conclusions) The proposed technical solutions in optimizing the parameters of plasma surfacing with powdered hard alloys make it possible to obtain wear-resistant coatings on the surfaces of restored machine parts 3-5 times higher than the wear re-sistance of hardened steel 45, taken as a reference standard.