The cracked part is analyzed with metallographic microscope and scanning electron microscope aiming at the peeling and cracking of hot rolled high strength beam steel plate during the process of bending. The results showed that many continuous punctiform or banded inclusions containing O,Al and Ti elements were distributed close to the surface lay-er at cracking;metallographic microstructure of decarburized layer on surface layer of steel plate was coarse equiaxed fer-rite. The analysis suggests that hard inclusions,TiO2 and Al2O3 destroy the continuity of product matrix and plasticity of surface layer is reduced by microstructures of oxidation and decarbonization,the matrix with inclusions fractures firstly in bending process,which makes the deformation of upper surface layer increase and it is out of tolerance range so that peeling and cracking are formed. The problem of lamellar cracking during bending for steel plate is solved by adopting the technolo-gy of pre-blowing argon in tundish to prevent oxide inclusion caused by secondary oxidation of molten steel at the initial stage of pouring.
关键词
高强大梁钢/起皮开裂/夹杂物/二次氧化
Key words
high strength beam steel/peeling and cracking/inclusions/secondary oxidation
维普
万方数据