Abstract: A batch of automobile hub bearing flanges produced by a factory cracked in the radius area of the large plate during the production. The cracking reasons were analyzed by means of macroscopic examination, chemical composition analysis, hardness test, metallographic examination, scanning electron microscope and energy spectrum analysis. The results show that the cracking of the hub bearing flange inner ring was mainly due to the residual shrinkage defects in raw materials caused by insufficient cutting volume at head and end area of the continuous casting slab. In the process of forging, the crack initiated from the shrinkage cavity and propagated along the deformation direction of the material, eventually leading to the cracking of the flange inner ring. It was recommended to strengthen the incoming quality inspection of raw materials, focusing on its macrostructure and shrinkage defects.