Study On Solidified Shell Thickness And Stress Analysis Of Slab

Continuous casting is key link in steel making. During the continuous casting process, change law of solidified shell thickness have had a significant impact to improve production process, meanwhile, analyzing state of stress and strain to help to in-depth know continuous casting process on the quality of impact.In this paper, solidified shell thickness of steel Q235 and Q345B had been tested for Xinjiang Bayi Iron and Steel Company by nail-shooting method. Four position of horizontal section are selected along the longitudinal direction, three position (1/2, 1/4and1/8) are selected along lateral position, obtained solidified shell thickness under different cooling process. By test results, end of solidification had been calculated, and analyzing change law of solidified shell thickness. Analysis shows that, cooling intensity of caster is greater, end point of solidification is approximately 20m-21m when casting speed is 1.2m/min for Q235, end point of solidification is approximately 23m-25m when casting speed is 1.3m/min for Q345B. Testing research may lay the foundation for optimizing parameters and improving efficiency and implementing dynamic soft reduction.In accordance with structural parameters of BA steel caster, adopted MSC.Marc Finite-Element software, established longitudinal two-dimensional plane model from meniscus to outlet of horizontal section. Boundary conditions of heat transfer model had been modified by test result of solidified shell thickness, obtained two-dimensional temperature field of steel Q235 slab continuous casting. Simulated longitudinal two-dimensional stress changes for slab continuous casting by using calculated temperature field, obtained different position stress-strain distribution. By comparing, the simulation results consistent with test results of slab surface temperature and solidified shell thickness. At the same time, calculated slab shrinkage comparison with the roll gap reduction settings of caster, obtained calculation and settings among the error is less than±0.2mm. Therefore, paper model has important value for evaluating of different cooling technology of roll gap shrinkage.By analyzing different position temperature field and stress field, the results show that maximum of surface equivalent thermal stress is the outlet of mold, equivalent thermal stress is less in early solidification for center position, because of temperature decreasing of end point, equivalent thermal stress increased rapidly. Therefore, ensure uniform cooling of continuous casting, reduce equivalent thermal stress and strain caused by changes of temperature, have had significant impacts to improve quality of continuous casting.