Method for producing low-hydrogen-content electroslag steel through CaO-containing slag system

The invention belongs to the technical field of electroslag remelting, and specifically relates to a method for producing low-hydrogen-content electroslag steel through a CaO-containing slag system. The method comprises the following steps: a, determining the slag quantity, wherein an electroslag steel ingot is of a phi 390 to 500mm type, and the slag quantity is controlled to be 43 to 95Kg per furnace; b, pre-melting slags, namely, feeding the slags to melt CaF2, then feeding Al2O3, finally feeding CaO and MgO, and performing electroslag remelting after the slags are completely molten; c, slowly cooling the steel ingot, namely, transferring an electroslag ingot into a sand pit after the electroslag is remolten, compactly burying the electroslag ingot, maintaining the temperature through the afterheat of the electroslag steel ingot and slowly cooling, and removing the electroslag steel ingot from the pit after the temperature of the steel ingot is not greater than 150 DEG C; d, dehydrogenizing and annealing the electroslag steel ingot, namely, maintaining the temperature of the electroslag steel ingot slowly cooled in step c for 30 to 40 hours in a furnace at the temperature of 670 to 690 DEG C, and removing the steel ingot from the furnace when the temperature of the steel ingot is not greater than 250 DEG C, so as to obtain the low-hydrogen-content electroslag steel. The method is carried out under normal-pressure conditions, and the operation is flexible; the hydrogen content of the produced electroslag steel is less than 1*10; the production cost is low.