某发动机支架发生断裂现象,采用宏观观察、扫描电镜分析、化学成分分析、金相检验等方法分析其断裂原因.结果表明:材料中C、Si元素含量接近技术要求的下限值,同时铸件壁厚较薄,使铸件的基体石墨形态为E型,不符合产品技术要求,导致发动机支架承受交变载荷时发生断裂.建议在材料中加入碳化硅,以提高C元素和Si元素的含量,试验浇注后铸件的石墨形态为A型,长度等级为4级,基体组织为珠光体,其余各项性能指标均满足设计要求.
The fracture phenomenon of an engine bracket was analyzed by macroscopic observation,scanning electron microscope analysis,chemical composition analysis,metallographic examination and other methods.The results show that the content of C and Si elements in the material was close to the lower limit of the technical requirements,and the wall thickness of the casting was thin,so that the matrix graphite of the casting was E-type,which did not meet the technical requirements of the product,resulting in the fracture of the engine bracket under alternating load.It was recommended to add silicon carbide to the material to increase the content of C and Si elements.After the test,the graphite morphology of the casting was A-type,the length grade was 4,and the matrix structure was pearlite.The rest of the performance indicators met the design requirements.
冀鹏;陈世荣
浙江零跑科技股份有限公司, 杭州 310000
金属材料
HT250灰铸铁;裂纹;石墨形态;硅碳比
HT250 gray cast iron;crack;graphite morphology;silicon carbon ratio
《理化检验-物理分册》 2024 (002)
21-23,27 / 4
10.11973/lhjy-wl202402006
评论