SAE1538MV非调质钢曲轴裂纹失效分析  

Fracture Failure Analysis of SAE 1538MV Non-Quenched and Tempered Steel Crankshaft

作　　者：李燊 吴锡华 陈启略 邱旻 Li Shen;Wu Xi-hua;Chen Qi-lue;Qiu Min(SAIC GM Wuling Automobile Company Ltd.,Liuzhou,Guangxi 545005 China;Liuzhou City Vocational College,Liuzhou,Guangxi 545036 China)

机构地区：[1]上汽通用五菱汽车股份有限公司,广西柳州545005 [2]柳州城市职业学院,广西柳州545036

出　　处：《内燃机与配件》2023年第23期67-69,共3页Internal Combustion Engine & Parts

摘　　要：曲轴第三连杆颈分模面处存在4mm横向裂纹,通过断口宏观分析、SEM微观分析、金相分析、硬度检测等手段,对SAE1538MV非调质钢曲轴裂纹产生原因进行分析。宏观分析表明,断口表面有经轻微高温灼烧后留下的发蓝现象;SEM分析发现曲轴发生脆性沿晶开裂,且裂纹边缘存在大量条状组织即MnS;金相分析发现,0°位置马氏体深度达到1.35mm,超出90°/180°/270°三个位置均值的35%,0°位置为分模面,同时也是裂纹所在区域。分析结果表明,曲轴分模面局部大量条状MnS杂质聚集,增加了曲轴淬裂倾向,淬火过程能量偏高导致曲轴开裂。There is a 4mm transverse crack at the die parting surface of the third connecting rod neck of the crankshaft.The cause of fractures in SAE1538MV non-quenched and tempered steel crankshafts are analyzed by means of fracture macroscopic analysis,microscopic analysis by SEM,metallographic analysis and hardness testing.The macroscopic analysis showed that bluing phenomenon remained on the fracture surface after mild high temperature burning.Microscopic analysis by SEM shows that there were the crankshaft has brittle intergranular fracture in crankshafts,and there were a lot of strip structures at the fracture edge,namely MnS.Metallographic analysis showed that the depth of martensite at 0-degree was 1.35mm,exceeding 35%of the mean value of the angle 90/180/270 degree.The 0-degree location was the mold parting surface and also the region where the crack was located.These results show that there were a large number of local strip MnS impurities accumulated in mold joints of crankshafts,which increases the tendency of crankshaft quenching fracture,and the instantaneous energy was too high during the quenching process leaded to crankshaft fracture.

关 键 词：非调质钢 曲轴 SEM 分模面 MNS 裂纹 淬火 

分 类 号：TG142[一般工业技术—材料科学与工程]