Prevention of Hot Cracks of Large-Sized Casting

The paper examines the possibility of computer modeling of the stressed state of large-sized castings with a developed surface using the example of the “Column” casting. During the research, the conditions for the occurrence of a stressed state of the casting body were studied and identified. It is noted that the result of stress is a violation of the continuity of the casting body during the formation of hot cracks. An analysis of the causes of cracking in the “Column” casting was carried out using computer modeling of the pouring and crystallization processes. Analysis of the dynamics of crystallization and changes in the strength characteristics of the structural elements of the casting made it possible to identify the reasons for the formation of defects along hot cracks in it. It has been established that the tensile strength of the alloy increases primarily in the stiffening ribs, and the outer walls of the casting have virtually no effect on the stress-strain state (SSS) of the product during its crystallization and cooling. Continuity failure occurs from the force interaction of the ribs with the casting core. The work mathematically describes the relationship between the geometric parameters of the stiffeners and the stresses arising in them due to the force interaction of the casting with the casting core. It has been determined that the technologically permissible amount of change in the geometry of the stiffener, equal to 100 mm, leads to a reduction in the resulting stresses by 30%. The introduction of changes in the geometry of the structural element confirmed the effectiveness of the technological recommendations, eliminating the violation of the continuity of the casting wall due to the formation of defects along hot cracks in the product, which was confirmed by the implementation certificate.