Method for reducing total oxygen of tundish of thick plate steel grade

The invention discloses a method for reducing total oxygen of a tundish of a thick plate steel grade, which comprises the following steps: controlling a converter to stop blowing free oxygen, adjusting a deoxidation process behind the converter, optimizing an RH (Ruhrstahl Heraeus) charging mode and improving an argon blowing mode after wire feeding, namely setting an oxygen blowing stop index of the converter to be lower than 600ppm, deoxidizing by adopting silicon iron, then adding an alloy, controlling the addition amount of the alloy in the early stage of RH to be more than 70% of the total input amount, and controlling the total amount of the alloy in the early stage of RH to be more than 70% of the total input amount; a soft blowing mode is adjusted, steel ladle argon blowing is adjusted firstly, the molten steel level slightly fluctuates, molten steel is not exposed, then calcium wires are fed, argon blowing is conducted in the whole wire feeding process, and soft argon blowing continues to be conducte