柴油机铸铁气缸套黑斑缺陷形成机理与解决方案研究

Study on Formation Mechanism and Solution of Black Spots Defect in Cast Iron Cylinder Liner of Diesel Engine

柴油机铸铁气缸套加工质量要求提高后,在气缸套外壁表现出大量黑斑缺陷,导致废品率上升。以缸套黑斑为研究对象,通过对比实验的方法,对大中型气缸套黑斑缺陷的产生原因进行系统研究,从孕育剂、浇注速度、组织硬化、冷却凝固条件、加工工艺和离心机主轴振动等方面,研究了黑斑缺陷的形成机理。结合黑斑缺陷形成的机理,提出了有效防控措施。结果表明,冷却凝固条件和离心机主轴异常振动直接影响黑斑缺陷的形成;黑斑缺陷显著下降,气缸套铸造废品率恢复正常。

After the processing quality requirement of diesel engine cast iron cylinder liner was improved,a large number of black spot defects appeared on the outer wall of cylinder liner,leading to the increase of reject rate.Taking the black spot of cylinder liner as the research object,through the method of comparative experiment,the causes of the black spot defect of large and medium cylinder liner were systematically studied.The formation mechanism of black spot defect was studied from inoculant,pouring speed,microstructure hardening,cooling and solidification conditions,processing technology and centrifuge spindle vibration.Combined with the formation mechanism of black spot defects,the efifective prevention and control measures are put forward.The results show that the conditions of cooling and solidification and the abnormal vibration of the centrifuge spindle directly affect the formation of black spot defects.The black spot defects decreased significantly,and the casting reject rate of cylinder liner returned to normal.