Method for casting steel ingots, castings and continuous casting slabs through seed crystal presetting technology

Abstract

The invention discloses a method for casting steel ingots, castings and continuous casting slabs through the seed crystal presetting technology. The method for casting the steel ingots, the castings and the continuous casting slabs through the seed crystal presetting technology is characterized by comprising the steps of 1, adding prefabricated seed crystals inside a material bin, wherein the addition quantity of the prefabricated seed crystals accounts for 1.5-5.0% of molten metal poured into a mould by the mass fraction; and 2, in the casting process, conveying the prefabricated seed crystals through an automatic feeding device system in a quantitative mode, wherein the prefabricated seed crystals are uniformly added into a pouring cup or a guide pipe through an automatic feeding pipeline in a timed and quantified mode for being uniformly mixed with molten steel streams and then enter the forming mould. The method has the advantages that the technology is simple, and composition segregation and columnar crystal growth are reduced; the super-cooling degree is lowered, the shrinkage value is reduced by 20-60%, a columnar crystal zone is reduced, a globular crystal zone is enlarged, inclusion gathering is reduced, chemical component segregation is greatly reduced, the grain size is small, and the hot crack sensitivity is effectively lowered.

Description

technical field [0001] The invention relates to the technical field of metallurgical casting, in particular to a method for casting steel ingots, castings and continuous casting slabs by adopting crystal seed preset technology. Background technique [0002] The casting of traditional steel ingots, castings and continuous casting slabs, whether in vacuum or in the atmosphere, directly injects molten steel into the mold through the ladle. From amorphous to finalized, it is an energy state transformation. In order to achieve a solid shape smoothly, A certain degree of superheat must be required to ensure the fluidity of its liquid metal. In the process of converting liquid to solid, a large amount of heat is stored in the liquid metal in the mold, which creates conditions for fractional crystallization, and in the crystallization process, accompanied by volume changes, the chemical composition is segregated And the grain grows thicker, especially for large steel ingots and cas...

AI Technical Summary

Problems solved by technology

In the process of converting liquid to solid, a large amount of heat is stored in the liquid metal in the mold, which creates conditions for fractional crystallization, and during the crystallization process, accompanied by volume changes, the chemical composition is segregated And the grain grows thicker, especially for large steel ingots and castings, which often leads to a decrease in mechanical properties and an increase in the tendency of hot cracking