Idan A. Technological support of operational properties of machine parts using combined methods of local strengthening of surfaces

Thesis for granting Candidate of Technical sciences Degree in specialty 05.02.08 – technology of mechanical engineering (13 – mechanical engineering). – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2020. The thesis is devoted to the solution of the scientific and practical problem of surface local hardening of details for increase of durability of products. The scientific novelty of the main results of the thesis is that for the first time: the obtained regularities of influence of the velocity of the laser beam to the depth of the hardened layer depending on the grade of steel in the processing of only a laser and combined technologies of hardening; developed a method of intensification of nitriding process, different from the existing previous laser treatment of the surface; developed a method of intensification of the process of boriding, which differs from previous existing laser surface treatment; developed mathematical models and nomograms influence the speed of movement of the laser beam and duration of nitriding on the thickness of the hardened layer and surface hardness. Practical value of work consists in the solution of important scientific and technical challenges in the development of technologies of combined hardening of surface layers of steel parts, which are advanced laser processing and subsequent chemical and thermal treatment.