Hot working process for eliminating blocky structures in large low-alloy steel forgings

The invention belongs to the field of hot working of steel and iron materials, particularly relates to a hot working process for eliminating a blocky structure in a large low-alloy steel forge piece, and is suitable for solving the problem of low impact toughness or serious fluctuation caused by thick and large blocky structures contained in a microscopic structure after heat treatment of the large low-alloy steel forge piece. The hot working process comprises the following specific steps: (1) carrying out high-temperature diffusion on a steel ingot or a blank and then carrying out multi-pass forging; (2) preheat treatment is reasonably designed, that is, after multiple passes of forging, one pass of proper annealing normalizing and tempering treatment is carried out; (3) controlling mass heat treatment consisting of quenching and tempering; and (4) reasonable hoisting and discharging are conducted, after standing and cooling are conducted in air, quenching is conducted in circulating water, and finally tempe