Causes and control measures of corner transverse cracks in fine blanking steel continuous casting billet

In order to study the causes of corner transverse cracks in fine blanking steel and formulate corresponding control measures, the temperature field distribution of continuous casting billet in secondary cooling zone was calculated by numerical simulation. On this basis, the section shrinkage of experimental steel under continuous casting conditions was measured by Gleeble 3500 thermal simulator. The composition, microstructure and inclusions in steel near the corner transverse crack were observed and analyzed by metallographic microscope and scanning electron microscope. The results show that the formation of corner transverse cracks is due to the formation of large size inclusions in the steel. During the bending process, the surface temperature of the corner of the continuous casting billet is at 710-765 ℃ in the brittle zone Ⅲ, and the crack propagates further to form corner transverse cracks. Some measures such as prolonging soft blowing time, controlling temperature drop during the process and adjusting the amount of secondary cooling water were put forward to effectively reduce the probability of corner transverse crack of continuous casting billet.