Simulation Of The Effect Of Reheating On Temperature And Stress Fields Of Hot Roller Steel Specimen

The hardfacing specimen was taken from the hot roller steel 60CrMnMo,whose temperature field during hardfacing and residual stress field afterhardfacing were measured. By using ANSYS software, the finite element model(FEM) was established based on the welding plane. Then, the temperature andthe stress fields during the process of hardfacing were simulated.Comparing the measured results of the temperature and residual stressfields with those simulated ones, they are keep agreement very well, whichprove this model for the hardfacing simulation is effective. Based on mentionedabove, the temperature field of the specimen during hardfacing was simulated.The temperature distribution of the specimen at the different times and curves ofthe temperature distribution at different section were obtained. Meanwhile, thetemperature field of the hardfacing specimen, which was cooled to 180s, and itsbalance state temperature field were simulated when the preheating temperaturewere 200℃, 300℃ and 400℃ respectively. The simulated results of thetemperature show that, the temperature distribution before and after thespecimen was cooled to 16s is different largely. The quantity of heat transmits tobelow surface quickly. When the specimen is cooled to180s, the temperaturefield became balance state. The temperature of the specimen can be increasedand the temperature difference between center and the side surface can bereduced by preheating, which makes temperature distribution of the specimenuniform.According the model and simulated results of the temperature field,several process stress fields at the key times when the martensite transformationoccurs in the specimen were simulated during hardfacing process withoutpreheating. Meanwhile, the stress fields when the specimen was cooled to 180sand residual stress were simulated when the preheating temperatures were 200℃, 300℃ and 400℃ respectively. The simulated results of the stress fieldshow that, without preheating, the tensile stress is appeared at the boundarybetween the heat-affected zone and hardfacing one, and the maximum ofthe tensile stress is located in the heat-affected zone inside of the specimen.Whit the increasing of the preheating temperature, the locations of the tensilestress maximum at three sections are similar, while, the stress distributions ofthe whole specimen are decreased.