高压共轨式喷油器开裂失效分析  

Cracking Failure Analysis of High Pressure Common Rail Injector

作　　者：颜婧 黄东亮 向洋 高勇 王砚民 冯继军 Yan Jing;Huang Dongliang;Xiang Yang;Gao Yong;Wang Yanmin;Feng Jijun(Technical Center of Dongfeng Commercial Vehicle Co.,Ltd.,Wuhan 430056)

机构地区：[1]东风商用车有限公司技术中心,武汉430056

出　　处：《汽车工艺与材料》2023年第8期62-66,共5页Automobile Technology & Material

摘　　要：某型柴油发动机在车辆行驶过程中发生失效,行驶里程仅为2743 km,经拆解后发现发动机第6缸高压共轨式喷油器的针阀体发生了轴向开裂,对其进行了失效分析。通过宏观痕迹分析、扫描电镜断口分析、能谱分析、金相分析及显微硬度测试,指出针阀体开裂的主要原因是球头处基体内存在纺锤形缺陷,该缺陷是含Zr、O等元素的原材料夹渣。针阀体材料为ASP钢,在其生产过程中,钢液经过雾化喷嘴(高密度氧化锆材质)时,喷嘴上的小块掉落钢液中形成夹渣,裂纹从夹渣处萌生并扩展,导致针阀体发生早期疲劳开裂。A diesel engine failed during running,its mileage was only more than 2743 kilometers.After disassembling,it was found that the needle valve body of high pressure common rail injector of cylinder 6 cracked in axial direction,failure analysis was performed.By means of macroscopic trace analysis,scanning electron microscope fracture analysis,energy spectrum analysis,metallographic analysis and microhardness test,it is pointed out that the main cause for the cracking of needle valve body is the existence of fusiform defect in the matrix of needle valve body head,which is the raw material slag containing Zr,O and other elements.The material of needle valve body is ASP steel,in its production process,when the liquid steel flows through the atomizing nozzle(high density zirconia material),a small part of the nozzle material falls into the liquid steel,forming the slag inclusion.The crack initiates and spreads from the slag inclusion,leading to early fatigue fracture of needle valve body.

关 键 词：高压共轨式喷油器 针阀体 锆氧夹渣 ASP 钢 早期疲劳开裂 

分 类 号：U465.2[一般工业技术—材料科学与工程]