Search academic texts

Information × Registration Number 0218U003886, 0117U007330 , R & D reports Title Theoretical and technological fundamentals of surfacing and welding processes. popup.stage_title Head Chigarev Valeriy Vasil'evich, Доктор технічних наук Registration Date 17-08-2018 Organization State Higher Educational Institution "Pryazovskyi State Technical University" popup.description2 Research Object - surfacing and welding of steels and alloys. A purpose of work - an increase of reliability of details of machines. A research method is theoretical and technological researches of processes of surfacing and welding. An analysis of the welding of copper with aluminum using the method of welding by friction and explosion is given. It was found that with increasing speed and decreasing running energy, due to a decrease in heat input, the deformation of the base metal and the welding stresses decrease. It is effective to reduce running energy by increasing the deposition rate, at which the rate of crystallization increases and the microstructure is crushed. A method has been developed for high-speed surfacing of bandaged support rollers at low running energy, which provides minimum welding stresses, fine-grained structure, increased crack resistance and no breakage of bandages. The analysis provides wide possibilities for regulating the chemical composition of welded metal and controlling metallurgical processes due to the charge of the powder tape when aluminum alloys are surfaced. Some data on substances used for etching in the preparation of samples for metallographic studies, as well as their negative impact on humans, are given. It has been established that when welding with powder strips of the same composition, in the same mode but with different designs, the form of penetration of the base metal is significantly different. Thus, it is possible to obtain a different form of penetration of the base metal, which can be used to obtain, under the influence of further wear, special profiles of the surface layer, including sawtooth, as well as for welding of dissimilar materials. On the basis of the analysis of working conditions and wear of working rolls, an energy-saving technological process of high-speed reinforcement and restoration of work rolls from high-carbon steels at low running energy has been developed, which provides minimum microcrystallization of the crystal lattice, microstress and dislocation density, grinding of the microstructure, increased fracture toughness, corrosion resistance and wear resistance of the deposited metal. Considered and implemented are developed welding materials with nitrogen, which make it possible to obtain metastable austenite in the welded metal of the surface layer, as well as the effect of heat treatment. An analysis of the improvement in the stability of deposition rates in 2 - 2.5 times is given by means of an improved powder electrode design. It is shown how the wear resistance of surfacing varies along the height of the weld bead. It is established that the deposited layer wears out by the mechanism, predominantly, the chipping of carbides, while grinding carbides and graphite as the distance from the surface of the roller provides a 1.6-fold increase in the erosion resistance of the welded layer. Product Description popup.authors Єфременко Богдан Васильович Алістратов Валерій Миколайович Білик Олександр Григорович Гавриш Павло Анатолійович Гулаков Сергій Володимирович Зусін Антон Михайлович Зусін Володимир Якович Чигарьов Валерій Васильович Щетинін Сергій Вікторович Щетиніна Віра Іванівна popup.nrat_date 2020-04-02 Close