Hot working diagram construction method of large-size non-quenched and tempered steel

The invention discloses a hot working diagram construction method of large-size non-quenched and tempered steel, which comprises the following steps: (1) carrying out hot compression on a non-quenchedand tempered steel sample under different deformation conditions, drawing hot working diagrams under different dependent variables, and giving a safe hot working process range and an instability interval; (2) carrying out hot compression simulation on the large-specification non-quenched and tempered steel in the safe hot working process range by adopting finite element software; (3) extracting temperature, strain and other data of different parts of the finite element simulation large-specification non-quenched and tempered steel; and (4) comparing data extracted by finite element simulationwith the hot working diagram to ensure that different parts of the large-specification non-quenched and tempered steel are located in a non-unstable area, further reducing to a proper hot working range, obtaining an optimal h