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Petryshak S.V., Bazarova G.S.
Presently details of hauling organs of coal conveyers, in particular, connecting links, make from the steel 35HGSA. These links work in the conditions of the reversal load, as a result there is destruction of link, and as a result stop of conveyer on repair.
From data [1] in 80% stops of coal scraper conveyers for repair it is related to breakage of connecting link. Lowering breakage of equipment it is possible to obtain different ways, one of which is replacement of the used in the present steel 35HGSA by other steel, for example, from the group of chrome -nickels steels (AISI 8620).
In spite of the fact that the AISI 8620 steel contains an expensive nickel, and now on possibility try to pass to not nickel steels, from the economic point of view it seems by the defensible step, as will allow to multiply the interrepair period of exploitation of coal scraper conveyer due to the increase of viscidity of steel of connecting link and lower propensity to brittle failure. The target of this work is the study of structure and physicomechanical properties of the AISI 8620 steel and establishment of principle possibility of replacement of steel by the 35HGSA steel AISI 8620.
For the given research on the "MMZ ISTIL" (UKRAINE)" samples from the AISI 8620 steel were selected (a 29 melting). On chemical composition this steel it is possible to identify how the steel 20HGNM. The statistical treatment was before conducted: equalizations of dependence of the basic controlled mechanical properties from maintenance of carbon and basic alloying elements in steel [2]. Statistical treatment was conducted by the "Statistica" program. Researches of macrostructure and microstructure of steel after the proper treatments produced: - 90 mm - billet after rolling; - the reforged billet on 30 mm; - 30 mm after annealing.
In the given work the influence of degree of deformation on a structure and properties of the AISI 8620 steel is considered. The present purveyances 30 was reforged on 25, 20, 15mm with the subsequent cooling in an oil and on air.
Forging was produced on an air-hammer with weight of the falling parts 400 kg.
A microstructure was studied on the models of etched in nitale, by the "Neophot 21" microscope the pictures of microstructure were done. With the use of the "ImageTool" program the correlation of structural constituents present in a structure after cooling on air is definite (ferrite, pearlite, bainite, martensite).