工程机械高强度螺栓的疲劳断裂分析  

Fracture Analysis of High Strength Bolts for Engineering Machinery

作　　者：王海金 WANG Hai-jin(School of Mechanical and Aerospace Engineering,Jilin University,Changchun 130025,China;XCMG Foundation Construction Machinery Co.,Ltd.,Jiangsu Xuzhou 221000,China)

机构地区：[1]吉林大学机械与航空航天工程学院,长春130025 [2]徐州徐工基础工程机械有限公司,江苏徐州221000

出　　处：《失效分析与预防》2024年第4期284-289,共6页Failure Analysis and Prevention

基　　金：国家自认科学基金(52272434)。

摘　　要：旋挖钻机是一种基础钻孔类工程机械,其工作装置钻桅普遍使用高强度螺栓连接,在其使用1000~2000 h时多次出现连接螺栓断裂故障。为了查明螺栓断裂原因,对断裂螺栓断口进行宏观及微观检查,对同一批次未使用螺栓进行拉伸性能、冲击性能、螺栓截面硬度分布、螺纹底部圆弧形貌、表面脱碳情况、表面和心部金相组织进行分析。结果表明:螺栓断裂形式为螺纹部位疲劳断裂。螺栓性能符合标准要求,但其螺纹牙型处存在尖锐、裂纹等缺陷,这些缺陷主要是由于滚丝过程中折叠以及搓丝板未进行定期更换修型所致。在螺栓承受较大的交变载荷情况下,易在牙型缺陷处造成初始起裂点,最终造成螺栓失效。Rotary drilling machines are a kind of foundation drilling engineering machinery,and their drilling masts are generally fastened with high-strength bolts.After a rotary drilling machine was used for 1000 to 2000 hours,the high-strength connection bolts of the drilling mast fractured for several times.In order to find out the fracture cause of the bolts,macro and micro inspection of the fracture of the fractured bolts was carried out,and tensile and impact properties testing,hardness distribution testing of cross section,thread bottom arc inspection,as well as analysis of surface decarburization and metallographic structure of surface and core were performed on the same batch of new bolts.The results show that the fracture mode of the bolts is fatigue fracture at thread.The mechanical properties of bolts meet the standard requirements,but there are sharp shapes,cracks and other defects at the thread.The form of the defects is mainly because there was folding in the process of wire rolling and the rolling plate was not replaced regularly.Under alternating load,cracks were inclined to initiate from the thread defects,eventually leading to the failure of the bolts.

关 键 词：高强度螺栓 疲劳断裂 工程机械 交变载荷 

分 类 号：TG115.5[金属学及工艺—物理冶金]