Reasonable solution cooling process can make hot working die steel obtain more strong and hard martensite structure without quenching cracking. In this paper, Deform software is used to simulate the solution cooling process of H13 module with large section size of 460 mm×700 mm×2000 mm, combined with the solution treatment process adopted in the practical production of the factory. By controlling the heat transfer coefficient and adjusting the alternating cooling time of water and air in combination with the phase transformation curve of continuous cooling calculated by Jmatpro software, the changes of temperature field, microstructure field and stress field in the module cooling process under different cooling modes were simulated, and the quenching cooling process was optimized. The results show that the forged H13 hot work die steel does not crack when the designed solution cooling method is used.
After heat treatment by isothermal spherospherification annealing process, the carbides are dissolved in the matrix, and the pearlite particles are smaller and more uniform, which can be rated as AS3. According to statistics, the average particle size of the carbides is 140nm, and a higher quality of the annealed structure is obtained. Therefore, the solution cooling process of water-cooled（180 s）+air-cooled （120 s）+water-cooled（85 s）+air-cooled（35 s）+oil-cooled（2100 s,core point cooling to 200 ℃） + natural air-cooled reduces the risk of module cracking and achieves more martensite structure, which can be applied to the production process of H13 hot work die steel.