Study on Formation Mechanism and Solution of Black Spots Defect in Cast Iron Cylinder Liner of Diesel Engine
Author of the article:PU Xiaotao;WEN Jun;LIU Yi;DENG Xiwen;LEI Jilin
Author's Workplace：Chengdu Galaxy Power Co.,Ltd.,Chengdu 610505,China;Faculty of Transportation Engineering,Kunming University of Science and Technology,Kunming 650500,China
Key Words：cylinder liner black spots defect formation mechanism research
Abstract：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.
