高碳钢弹片疲劳断裂失效分析及热处理工艺改进  

Fatigue fracture failure analysis and heat treatment process improvement of high carbon steel spring component

作　　者：王亚蒙 徐志文 郜晋锋 许金玲 Wang Yameng;Xu Zhiwen;Gao Jinfeng;Xu Jinling(Guangdong Lingyi Intelligent Manufacturing Co.,Ltd.,Dongguan Guangdong 523000,China)

机构地区：[1]广东领益智造股份有限公司,广东东莞523000

出　　处：《金属热处理》2024年第6期295-300,共6页Heat Treatment of Metals

摘　　要：应用于某无线耳机充电器的高碳钢弹片在疲劳试验中出现开裂,通过对弹片进行断口、显微组织观察和硬度检测,结合其热处理工艺和疲劳试验工况进行综合分析,确定了弹片的断裂模式及产生原因。结果表明,断裂模式为低应力疲劳断裂,产生原因是弹片经等温淬火和回火后组织内有大量的未溶碳化物,在耐久测试中,弹性臂的圆弧过渡区产生应力集中引发裂纹萌生和扩展,进而导致断裂。结合实际生产条件,对热处理工艺进行了改进设计,取得了良好的效果。最佳热处理工艺为:碳势0.75%下830℃×20 min淬火+305℃×35 min盐浴等温淬火+305℃×90 min回火。经改进工艺处理后的弹片,维氏硬度为584 HV0.2,耐久试验测试寿命均超过9×10^(4)次。High carbon steel spring component of wireless headphone charger cracked in the fatigue test,for which the fracture mode and cause were determined through observation of the fracture and microstructure,hardness test,and combining with the heat treatment process and fatigue test conditions.The results show that the fracture mode is low stress fatigue fracture,the cause of which is that a lot of undissolved carbides exist in the microstructure after austempering and tempering,leading to stress concentration in the circular arc transition zone of the elastic arm of the spring component in the durability test,then leading to crack initiation,propagation,and finally resulting in fracture.By improving heat treatment process according to the actual production conditions,the optimum heat treatment process is found as:quenching at 830℃for 20 min with carbon potential 0.75%+salt bath austempering at 305℃for 35 min+tempering at 305℃for 90 min.After heat treatment with the improved process,the Vickers hardness of the high carbon steel spring component is 584 HV0.2,and the durability test life is over 90000 times.

关 键 词：1074钢弹片 疲劳断裂 热处理 显微组织 硬度 

分 类 号：TG156[金属学及工艺—热处理]