大截面H13钢固溶热处理过程数值模拟与工艺研究

Numerical Simulation and Process Research on Cooling after Solution Heat Treatment for Large Section H13 Steel

摘要:

合理的固溶冷却工艺可以使热作模具钢在不发生淬火开裂现象的情况下，获得更多强硬性高的马氏体组织。利用Deform软件，结合工厂实际生产中采用的固溶处理工艺，对尺寸为460 mm×700 mm×2000 mm的大截面H13模块进行固溶冷却过程模拟。通过控制换热系数及结合Jmatpro软件，计算得到连续冷却相变曲线；通过控制水空交替冷却时间，模拟不同冷却方式下模块冷却过程中温度场、组织场和应力场的变化，优化淬火冷却工艺。结果表明：采用水冷（180 s）+空冷（120 s）+水冷（85 s）+空冷（35 s）+油冷（2100 s，心部点冷至200 ℃）+自然空冷的固溶冷却方式，对锻造态H13热作模具钢进行处理时材料并未开裂；进行等温球化退火工艺热处理后，碳化物多溶解在基体中且珠光体颗粒更加细小且均匀（可评为AS3级），经统计碳化物平均粒径为140 nm，获得了更高品质的退火态组织。表明设计的固溶处理工艺能降低模块开裂的风险，并且获得较多的马氏体组织，可应用于H13热作模具钢的生产过程中。

Abstract:

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.