Actual Problems in Machine Building 2017 Vol. 4 No. 1

Actual Problems in Machine Building. Vol. 4. N 1. 2017 Materials Science in Machine Building ____________________________________________________________________ 130 TECHNOLOGICAL FEATURES OF THE HEAT TREATMENT OF DETAILS RESTORED WITH ELECTRIC CONTACT SURFACING Berezshnaya O.V. , Ph.D. (Engineering), Associate Professor, e-mail: elena_kassova@mail.ru Donbass State Engineering Academy, 72 Shkadinova, Kramatorsk, Donetsk region, 84313, Ukraine Abstract The influence of heat treatment on the structural changes of the deposited layer on the surface of structural steel components, remanufactured electric contact deposition is investigated. Preliminary experiments showed that high-frequency heating since the total number of free ferrite in the structure of the deposited layer is somewhat smaller than in the conventional furnace, thereby increasing the propensity to stress concentration in the restored product. To obtain the desired structure it is suggested to provide a cooling of the deposited samples at slower rate after induction heating. As a result of quantitative metallographic analysis found that the use as a cooling environment of silver particulate graphite ensures slow cooling of the deposited specimens after heat treatment, thereby increasing the content of excess ferrite in deposited layer. Also slow isothermal cooling environment leads to a significant increase in grain size as compared with the grain obtained by cooling the deposited samples in air. Keywords slow cooling, heat treatment, electric contact surfacing