Method for reducing alloy usage amount in P20 steel smelting

The invention belongs to the technical field of steelmaking, and particularly relates to a method for reducing alloy usage amount in P20 steel smelting, which comprises the following steps: (1) when 25wt%-28wt% of steel is tapped from a converter, adding ferrochrome and silicon-manganese alloy, and then adding slag charge until the tapping is finished; (2) after the molten steel reaches the LF furnace, blowing off slag crust on the surface of the molten steel by using argon of 90-110 cubic meters per hour until the slag crust is completely changed into a liquid state, (3) supplying power to heat by using first power, then adding slag charge, and intermittently providing argon at the same time, so that slag melting is complete; then, the second power is changed for power transmission and temperature rise, and the argon flow is lowered; after the total power transmission time is longer than 8 min, alloy is added; (4) carrying out second-power power transmission and temperature rise, and sampling I; and (5) prep