The three dimensional thermo-mechanical coupling model of temperature field for medium and heavy plate during straightening process is established by finite element software ABAQUS. The temperature distribution and change of temperature of 20 mm plate with initial temperature 520 ℃ and 55 mm plate with initial temperature 605 Y along plate longitudinal

transverse and thickness direction during straightening process are obtained by simulated calculation and analysis on 0.45 C steel medium and heavy plate

and the effect of plate straightening initial temperature (20 mm plate 420-620 ℃ and 55 mm plate 505-705 ℃) and initial curvature (0.07-0.20) on residual stress in straightened plate is analyzed. Calculated results show that the lower temperature before straightening

the larger residual stress after straightening ； for 520 ℃ 20 mm plate

the temperature of plate after straightening is 505.4 ℃ and the straightening force is 2 161.69 kN

for 605 ℃ 55 mm plate the temperature of plate after straightening is 589.3 °C and the straightening force is 4565.49 kN

their measured values are respectively 507 ℃

2272.93 kN and 591 Y

4397.94 kN. It indicated that the error of calculated value is minor.