ЗАСТОСУВАННЯ РОЗРЯДНИКІВ НАПРУЖЕНЬ В ОСНОВНИХ ВУЗЛАХ ТЕХНОЛОГІЧНОГО УСТАТКУВАННЯ МБЛЗ

Abstract

Presence of cracks and other surface defects is completely prohibited at exploitation of industrial facilities. This condition is of vital importance for component parts of a complex of big equipment. For example, for continuous casting machines (CCMs), whose total weight exceeds several thousand metric tons a failure of a single component part can lead to serious consequences, due to imminent hue material losses. Such hard conditions of such equipment not only influence its operation, reducing its service life, but also may have a negative impact on the quality of production. Such negative influence can be expressed in the following way: regulation of the main units may be altered following overheating of the equipment, due to thermal expansion of mostly heated elements. In case of presence of cracks in the most loaded unit of dummy bar –its head part its bearing capacity may be altered and appearance of excessive deformations may not be excluded, i.e. its transverse dimensions may be changed. Besides, cracks in the locking part of the dummy bar are out of the question, in order to avoid solidification of liquid metal in cracks.The problem of reducing intensity of cracks formation can be solved in different ways. Its practical solution depends upon the part’s design and peculiarities of its loading. For operation of dummy bars of slab casting CCMs it should be noted that this problem is closely connected with asymmetric design of dummy bars heads and one-way heat delivery and removal for its locking part. The finite elements method was used for the analysis of stress-strain state in the article. Three-dimensional simulation models were divided into finite elements and after that they underwent various theoretically possible loads. Simulation made it possible to establish the most vulnerable sections of the design, undergoing most severe loads, in case they are applied. Particularly, it was found out that the edge parts of transverse section of a dummy bar head experience the biggest deformations, consequently, cracks can spring up at a certain pitch and develop on the surface of the projection of the lock. The analysis of the initial data showed that for reduction of thermal strain in the lock projection it was necessary to make deformation inside its upper layers more free. It will be is possible if a transverse slot is made, dividing the projection length into two elements. Heating and cooling of the surface lock’s layer could become safer, at that, from the point of view of elongating stresses, thus reducing the probability of cracks formation.