40Cr钢紧固轴疲劳断裂原因分析及改进  

Analysis and improvement of fatigue fracture reasons for 40Cr steel screw bolt

作　　者：庞维彬 郑东方 潘冬 侯震彪 刘志伟 PANG Weibin;ZHENG Dongfang;PAN Dong;HOU Zhenbiao;LIU Zhiwei(CRDC(Jinan)Electrical Equipment Co.,Ltd.,Jinan 250200,Shandong,China;Jinan Railway Material Industry Group Co.,Ltd.,Jinan 250001,Shandong,China)

机构地区：[1]铁设(济南)电气设备有限公司,山东济南250200 [2]济南铁路物资工业集团有限公司,山东济南250001

出　　处：《金属加工（热加工）》2024年第6期50-53,共4页MW Metal Forming

摘　　要：一批40Cr钢紧固轴在疲劳试验检测过程中连续出现早期断裂,达不到试验要求次数。为了探索此批紧固轴断裂的原因,对断裂件进行了成分分析、硬度检测、宏观断口分析与扫描电镜、金相组织检测,以及螺纹外形轮廓测量。结果表明:紧固轴的螺纹牙底过渡圆弧半径R≤0.07mm,且调质后的金相组织超过6级,不合格,导致疲劳试验检测中的紧固轴因螺纹根部应力集中形成细微裂纹并逐步扩展而断裂。通过分析讨论,制定改进措施并严格控制紧固轴的生产过程,最终使紧固轴的力学性能达到了技术要求。A batch of 40Cr steel screw bolt broke continuously early during the fatigue test,failing to meet the required times of test.In order to explore the cause of this batch of fastening shaft fracture,the fracture component analysis,hardness detection,macro fracture analysis and scanning electron microscope,metallographic tissue detection and thread contour measurement,the results show that the thread of fastening shaft bottom transition arc radius R≤0.07mm,and the alignment more than 6 level unqualified,resulting in the fastening shaft fatigue test thread root stress concentration formed subtle cracks and gradually expand and fracture.Through analysis and discussion,the improvement measures are formulated and the production process of the fastening shaft is strictly controlled,and finally the mechanical properties of the fastening shaft meet the technical requirements.

关 键 词：紧固轴 疲劳断裂 应力集中 过渡圆弧 

分 类 号：TG115[金属学及工艺—物理冶金] TG142.1[金属学及工艺—金属学]