7Ni steel medium plate and production method and application thereof

The invention discloses a 7Ni steel medium plate and a production method and application thereof. The production method comprises the steps of molten iron pretreatment, converter smelting, LF and RH/VD refining, continuous casting, heating furnace heating, rolling, MULPIC cooling, finishing and heat treatment. The surface of the casting blank is ground, polished and sprayed with an anti-oxidation coating before being heated, and low-temperature steel burning of a heating furnace is combined, so that the oxide scale pressing-in and double skin defects on the surface of a steel plate are effectively reduced; the rough rolling process is large in rolling reduction, the finish rolling temperature is controlled in the finish rolling process, and the grain size is effectively controlled; a one-time quenching and tempering process is adopted in the heat treatment process, offline quenching is replaced by online quenching, the one-time quenching procedure is reduced compared with a conventional quenching, quenching a