Abstract：During the magnetic particle test of the S38MnSiV steel crank shaft produced in a factory，it was found that there were linear magnetic marks on the journal of the crank shaft，which was not allowed in the magnetic particle test of the crank shaft.The cause of unqualified magnetic particle test of S38MnSiV steel crank shaft was studied by means of optical emission spectrometer（OES）， optical microscope（OM）and scanning electron microscopy（SEM）. The results showed that the core steel with segregation of alloying elements migrated to the surface of the journal during the forging process，resulting in the formation of the residual austenite on the surface of the journal during quenching. The differ-enceinmagnetic permeability betweenthe residual austenite and martensite caused the magnetic marks.Corresponding technical improvement measures were proposed for such magneticmarks.
董凤奎，龙慧芝，廖美华，何荣福，李世晶. S38MnSiV钢曲轴磁粉探伤不合格原因分析[J]. 物理测试, 2019, 37(2): 40-43.
宝武集团广东韶关钢铁有限公司，广东 韶关 512123. Analysis of unqualified reason for magnetic particle test of S38MnSiV steel crank shaft. PHYSICS EXAMINATION AND TESTING, 2019, 37(2): 40-43.
2019, Vol. 37 
