Modification of transportation means units, operating under the heaviest loads at high temperatures

Technological transport, its units operating at high temperatures is employed in iron and steel and coke-chemical industry. Elements of such transportation facilities undergo very non-uniform loads. Investigations show that strength of separate mostly loaded sections of separate units exert direct limitations upon the total service lives of these transportation means, having an indirect influence upon reliability and economic indices of the entire production processes. As a result of non-uniform wearing many bulky metal parts get broken, prior to the expiry of their specified service lives terms. Substantial expenses of enterprises on repair and maintenance of technological transport increase production, equipment repairs costs and total production costs, therefore the problem of increasing service lives of the mostly loaded units still needs to be solved. The article deals with the analysis of the existing methods of improving strength of units, operating under the heaviest loads that are the first to fail. The main reasons for these parts failure at high tem-perature ranges are a decline in mechanical properties of the material and changes of its structure. Such processes may occur both at prolonged operation of the material at high temperature and at its thermo-cycling. Decarburization is developed at high temperatures on the surface and adjoining areas of any part; it resulting in changes in the structure and mechanical properties of metal. Strength properties and especially plasticity properties decline. Due to these phenomena the majority of exploitation defects start forming on surface of the part. To improve such parts and to increase their service lives a method of alloying parts was proposed, by which it was possible to increase strength on a particular section of a part at minimal consumption of alloying elements. As compared to conventional alloying methods, in which alloying elements are used in large quantities and distributed throughout the entire volume of a part, here, consumption of costly elements is 20-30 times less, that could be beneficial for consumers of such parts. It is to ensure maximum service lives of equipment, the expenses on costly alloying elements being drastically reduced. The method was illustrated on the example of the head part of input device for continuous casting machines