40钢球头挂环的断裂失效分析  

Fracture Failure Analysis of 40 Steel Ball Head Hanging Ring

作　　者：林双平 钟振前[1] 司红[1] 李云玲 高群 郑凯 LIN Shuangping;ZHONG Zhenqian;SI Hong;LI Yunling;GAO Qtm;ZHENG Kai(Central Iron and Steel Research Institute,Beijing 100081,China;No.714Research Institute of China Shipbuliding Industry Corporation,Beijing 100097,China)

机构地区：[1]钢铁研究总院,北京100081 [2]中国船舶重工集团公司第七一四研究所,北京100097

出　　处：《热加工工艺》2018年第22期256-260,共5页Hot Working Technology

摘　　要：输电线路球头挂环在使用过程中发生断裂。通过宏观断口特征、微观断口、化学成分、力学性能和显微组织等对球头挂环进行了断裂原因分析。结果表明,球头挂环在双向循环弯曲载荷作用下发生多源疲劳断裂,疲劳源位于球头挂环两侧次表层,裂纹沿径向由次表层向心部扩展,最后瞬断区位于心部;球头挂环次表层的基材表面尺寸不等的显微凹坑(10~30μm)和硬度较低(184HV0.05)的脱碳层的存在,使得球头挂环在根部的显微凹坑底部的最大应力集中处萌生裂纹,这是造成球头挂环断裂失效的重要原因。在球头挂环加工以及后续热处理过程中,避免基材表面产生显微凹坑缺陷和防止表面发生脱碳,是减少球头挂环发生疲劳断裂失效的有效措施。The ball head ring of transmission line is broken during operation. The fracture analysis of ball head ring was carried out by means of macroscopic fracture characteristics, micro fracture surface, chemical composition, mechanical properties and microstructure analysis. The results show that, under the action of bidirectional cyclic bending load, the ball head ring is subjected to multi-source fatigue fracture. The fatigue source is located at both sides of the ball head ring, the crack propagates along the radial direction from the subsurface to the center, and the final transient fracture zone is located at the center. The existence of the microcrater with different sizes on spherical ring hanging rings subsurface(10-30 μm) and decarburized layer with low hardness(184 HV0.05) makes the ball head ring crack at the maximum stress concentration at the bottom of the microcrater in the root, which is an important reason for the failure of the ball-head ring. In the process of ball head hoisting and heat treatment, it is an effective measure to reduce fatigue fracture failure of ball head hanging ring by avoiding micro-pit defects and decarbonization on the surface of the substrate.

关 键 词：球头挂环 断口形貌 疲劳裂纹 失效分析 

分 类 号：TG111.91[金属学及工艺—物理冶金] TG142.33[金属学及工艺—金属学]