Abstract: In the assembly process of tube components, the installation of stainless steel tube and bushing often experiences extrusion flaring process. The relationship between material performance and flaring cracks were analyzed by optical microscopy. The results show that the stainless steel tube with flaring cracks had no obvious plastic deformation. If ferrite accounts for more than 20%(volume fraction), the plasticity of austenitic stainless steel will dramatically decline. The poor plasticity of the material is main cause for cracking. It has been proved that the tubes under annealed state can effectively avoid flaring cracks.