防脱盘断裂失效分析  

FRACTURE FAILURE ANALYSIS ON DISK OF PREVENTION ABSCISSION

作　　者：李茂林[1,2] 杨承刚[1] 严峰鹤[1] 时艳清[2] 

机构地区：[1]环境保护部核与辐射安全中心,北京100082 [2]北京北方车辆集团有限公司,北京100072

出　　处：《机械强度》2013年第5期700-703,共4页Journal of Mechanical Strength

摘　　要：针对某重型车辆关键零部件之一防脱盘的大批量断裂现象,应用金相显微镜、直读光谱仪、洛氏硬度计、显微硬度测量仪等分析测试手段,对其进行断裂失效分析。分析认为:断口表面平齐粗糙,没有可见的塑性变形;并且其边缘没有剪切唇边,属于脆性断裂。导致防脱盘断裂的主要原因是大量铸造缩松和夹杂物的存在,以及严重的枝晶偏析增大组织应力,从而在使用过程中,易于形成早期裂纹,最终发生断裂。为防止此断裂的再度发生,在其制造加工过程中,可以遵循以下原则:冶炼过程减少夹杂物的产生,浇铸过程避免缩松的形成,通过扩散退火消除铸件内部的枝晶偏析。According to the phenomena of Disk of Prevention Abscission （DPA） which is one of the key parts in heavy vehicle fractured vastly, the reason of fracture failure was analyzed by means of metallographic microscope, direct-reading optical spectrometer, rock well hardness tester, mieroharduess instrument. Experimental results showed that the surface of fracture was planished and coarse. Not only visible plastic deformation could not be found, but also shear lip was not exist on the fracture edge. So the fracture belonged to brittle fracture. The prime factor leads to fracture about DPA is lots of casting shrinkage porosity and impurities exist in DPA, and severe dendritic segregation may increase structural stress. Initial cracks are easy formed in the using process and fracture is caused in the end. In order to avoid fracture again, following principle can be adopted： decreasing impurities during at smehing, avoiding shrinkage porosity during casting, and dendritic segregation of casting must been cancelled by diffusion annealing.

关 键 词：防脱盘 脆性断裂 缩松 夹杂物 枝晶偏析 

分 类 号：TG115.21[金属学及工艺—物理冶金]