制动盘黑斑缺陷的成因分析与防止措施

Black Spot Formation Reason and Prevention Measures of Brake Disc

介绍了实心制动盘和通风制动盘铸件的结构,铸件在加工后发现在制动面根部出现黑斑缺陷,其外观形貌和出现部位类似,仅通过宏观形貌很难区分。利用EVO18钨丝灯扫描电镜、OXFORD电制冷能谱、ZEISS金相显微镜对缺陷的微观形貌进行检验对比,发现两种缺陷存在明显差别,结合形成机理,认为两种缺陷分别为缩松和石墨粗大。最后通过增加冒口颈模数,增大冒口补缩通道,解决了实心制动盘的缩松问题;通过在安装面根部以及摩擦面与安装面之间铸出凹槽,减少局部热节,解决了石墨粗大问题。

The casting structures of the solid and ventilated brake discs were introduced.Black spots defect was found at root place of the braking surface after casting being machined,its outer morphology was similar to the occurring location,it's very hard to distinguish only according the macroscopic appearance.The micro morphology of the defects were compared by using EVO18 tungsten wire lamp SEM,OXFORD and ZEISS metallographic scopes,it was found there were obviously difference between two sorts defects.Combining with formation mechanism,it was considered that two sorts defects were shrinkage porosities and large graphite respectively.Finally,by increasing modulus of riser neck to enlarge feeding channel of the riser,the shrinkage porosities problem was solved,by cast-making concave grooves at root location of mounting surface and friction surface to reduce local hot spots,the large graphite problem was solved.