On the theory of crystallization and formation of the structure of castings and ingots

This paper is devoted to the development of the theory of crystallization and to the evaluation of the effect of cooling conditions on the structure of castings in order to elucidate the reasons for the ambiguous relation of the grain size with the cooling conditions and between the macrostructure and microstructure. As a result, the conception for the formation of sizes of macrograins, which takes into account the joint effect of the cooling rate and the effect of insoluble impurities on the nucleation rate, was proposed and tested for the generalized experimental data. Based on this conception, a scientific explanation for variations in the relation of the grain size with the cooling rate and between the macrostructure and the microstructure was provided.