Burtsev S. Increase of operational durability of products made of high-duty cast iron

The thesis deals with an important scientific problem for metallurgical and machine-building industry of Ukraine directed to the increase of quality and wear-resistance (rolling rolls for thin-walled parts) made of high-duty cast iron. The application of high-duty cast iron for purpose castings for various purposes demands specific approaches taking into the consideration their constructive features and requirements to the structure and the level of physical-mechanical and operational features. During the manufacturing of products for various purposes, one can observe deviations in the formation of homogeneous structure. To achieve the goal the basic factors affecting the structure with the appearance of 'white and black spots' have been investigated. By means of theoretical and experimental investigation it has been established that homogeneous structure in castings of different mass can be provided by crystallization and specific approaches to modification. The investigations show that it is possible to adjust the conditions of crystallization of rolling rolls due to the cast calibration. This provides the increase in crystallization rate and obtaining of homogeneous structure through the whole perimeter with even wear. Several approaches to the choice of the rolling roll technique have been examined. The best results have been achieved under the conditions of their production in the shaped metal form and in the developed way of their modification. The affect of technological parameters onto the stress and structure of product alloys has been studied. On the base of the investigation, the chemical content for alloys, the method of modification, parameters of casting of products and the methods of their quality and properties control have been proposed. The economic effect from the introduction of the invention has made up 1.4 mln. UAH profit.