Wang Zaiyou，Chen Huangpu，Xu Yingge，Zhu Jinhua
(State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China)
Abstract：Using a CMS-120 whirling arm vacuum erosion rig and KS-60 vibratory cavitation magnetostrictive instrument, tests on erosion at impact angle of 90 degrees and cavitation erosion for the 20SiMn (0.2%C-0.6%SiMn) steel were carried out. The results show that the erosion process of the steel is divided into three stages-incubation, mass-increase and steady periods; and its cavitation erosion process consists of four stages- incubation, accumulation, attenuation and stationary periods. Cracks principally initiate and propagate along crystal boundaries both in erosion and cavitation erosion processes, and the failure mechanisms are intergranular failure and etching pits in grain interior due to local microzone mechanical effect. Crystal grain's peeling off is one of the major failure modes in cavitation erosion process.
Keywords：erosion；cavitation erosion；failure mechanism；intergranular failure；etching pit