灰铸铁水泵壳体铸件裂纹形成原因分析OACSTPCD

TAutomobile water pump shell is one of the components of automobile engine cooling system,and its quality has an important impact on the normal operation of engine cooling system.The casting material of the automobile water pump shell produced by a company is HT200.The cracking phenomenon occurs in the casting during the production process.In order to analyze the reasons for the crack defects,the microstructure of the casting is characterized by metallography microscope(OM)and scanning electron microscope(SEM),and the phase composition and mechanical properties of the casting are detected by energy Spectrum analyzer(EDS)and hardness tester.The experimental results show that the crack morphology is broken line with uneven width,and the oxidation degree of the crack fracture is serious,which is judged as a hot tearing.The crack forming is a composite effect of several causes including the metallographic structure of the casting does not meet the design requirements,the excessive content of S element in the fracture,the existence of oxide inclusion and the appearance of stress concentration area in the casting process,and so on.