重载汽车用U型螺栓断裂失效分析  

Fracture Failure Analysis of U-bolts Used in Heavy Duty Vehicles

作　　者：黄山 骆玉城 HUANG Shan;LUO Yu-cheng(Guilin Fuda Gear Co.,Ltd.,Guilin Guangxi 541199,China;Guilin Fuda Co.,Ltd.,Guilin Guangxi 541199,China)

机构地区：[1]桂林福达齿轮有限公司,广西桂林541199 [2]桂林福达股份有限公司,广西桂林541199

出　　处：《热处理技术与装备》2023年第1期35-39,共5页Heat Treatment Technology and Equipment

摘　　要：某U型螺栓在重载汽车底盘耐久试验过程中发生断裂失效,失效行驶总里程约为2100 km。本文通过断口分析和理化检验确定U型螺栓断裂失效的原因,同时讨论了螺纹表面黑色组织的形成原因及其对断裂失效的影响,并提出了针对黑色组织的改善措施。U型螺栓在服役过程中发生松动,导致其受到周期性冲击应力的作用,这是发生疲劳断裂失效的主要原因;同时,螺纹表面深度8~15μm的网状黑色组织,也促进了裂纹的萌生和扩展。A U-bolt broke and failed in durability test of heavy-duty vehicle chassis, with a total mileage of 2100 km. Through fracture analysis and physical and chemical examination, the cause of fracture failure of U-bolt was determined. At the same time, the formation cause of black structure on thread surface and its influence on fracture failure were discussed, and the measures to improve the black structure were put forward. The results showed that the main reason of fatigue fracture failure was that the U-bolt was loosened during service and subjected to periodic impact stress. And the reticular black structure with the depth of 8 to 15 μm on the thread surface promoted the initiation and propagation of cracks.

关 键 词：U型螺栓 疲劳断裂失效 松动 周期性冲击应力 网状黑色组织 

分 类 号：TG115[金属学及工艺—物理冶金]