Manufacturing method of highly clean tool steel with improved macro-micro solidification structure

摘要

The present invention relates to a high-clean alloy tool steel (hot tool steel, cold tool steel) to which a light rare earth element (REM) and REM + Ca are added based on a vacuum induction furnace melting furnace and an electric melting furnace.;A method for manufacturing a high-clean hot tool steel according to the present invention comprises the steps of: C: 0.1 to 1.0%, Si: 0.2 to 0.8%, Mn: 0.3 to 4.0%, Ni: 0.001 to 4.0% And the balance of Fe and Cu in the electric furnace can be contained in an amount of 0.1 to 5% by weight, Fe: 0.3 to 4.0%, V: 0.1 to 3.5%, W: 0.005 to 0.2% and Al: 0.005 to 0.1% The molten steel consisting of trace impurities is dissolved. Then, the molten steel is deoxidized and desulfurized at a predetermined degree of vacuum. Thereafter, a step of adding a light rare earth element to the deoxidized and desulfurized molten steel so that the weight percentage is in the range of 0.0002% to 0.25%, and then cooling the molten steel to produce a steel ingot.