摘要
利用剪切试验研究了焊接电流对铁路信号继电器银接点点焊质量的影响,并采用金相显微镜和扫描电子显微镜观察了不同焊接电流下焊接接头剪切断裂行为。结果表明:随着焊接电流的增大,焊接接头的剪切强度先升高后降低,随后又迅速升高;当焊接电流为7.0 kA时,剪切强度达到585 N,此时焊核质量最高。结合焊接接头剪切断裂行为分析发现,相对于空穴缺陷,焊核尺寸是影响接点点焊接头剪切性能的主要因素,焊核尺寸的增大会引起焊接接头界面区域的剪切强度增加。
This paper conducts a shearing test to study the impact of welding current on the spot welding quality of the silver contacts of railway signal relays,and uses a metalloscope and a scanning electron microscope to observe the shearing and fracturing behaviors of welded splices under diff erent welding currents.The results show that as the welding current increases,the shear strength of the welded splices fi rst increases,and then decreases,followed by a rapid rise.When the welding current is 7.0 kA,the shear strength reaches 585 N,which is when the quality of the welding nugget is the highest.Analysis based on the shearing and fracturing behaviors of the welded splices found that,with respect to the defects of pores in welds,the size of the welding nuggets is the main factor aff ecting the shear performance of the spot welding splices of the relay contacts.An increase in the size of the welding nuggets will cause an increase in the shear strength of the weld interface area.
出处
《铁路通信信号工程技术》
2024年第S1期133-136,共4页
Railway Signalling & Communication Engineering
关键词
继电器
电阻点焊
焊接强度
失效机理
relay
resistance spot welding
welding strength
failure mechanism
