YG6X硬质合金/65Mn钢钎焊接头组织与性能研究

Study on Microstructure and Properties of Brazed Joints Using YG6X Cemented Carbide and 65Mn Steel

  • 摘要: 为满足圆形锯齿切割锯片对高耐磨性与强韧性的综合需求,本研究采用BAg5CuZnNiMnIn合金作为钎料,通过高频感应钎焊技术实现了YG6X硬质合金(锯片齿尖)与65Mn钢(锯片基体)的可靠连接。借助金相显微镜(OM)、扫描电子显微镜(SEM)及能谱分析(EDS)对钎焊接头的微观组织与元素分布进行表征,通过剪切强度测试探究焊缝宽度和感应回火温度对接头力学性能的影响。结果表明:钎焊接头形成稳定冶金结合,无明显裂纹,但焊缝中存在部分气孔,呈现出“65Mn钢-焊缝-YG6X硬质合金”的结构特征;Fe、Cu、Co等元素在界面处发生互扩散;焊缝宽度对接头强度影响显著,宽度由20um减小至8um时,剪切强度提升约27.2%;感应回火温度对焊缝剪切强度具有调控作用,400℃回火时强度最优(161.3MPa),较未回火状态提升20MPa,回火温度超过500℃后,剪切强度低于未回火试样。

     

    Abstract: To meet the comprehensive requirements for high wear resistance and toughness in circular saw blades with serrated teeth, this study employed BAg5CuZnNiMnIn alloy as the brazing filler material. Through high-frequency induction brazing technology, a reliable connection was achieved between YG6X cemented carbide (saw blade tooth tip) and 65Mn steel (saw blade body). Microstructure and element distribution of the brazed joint were characterized using optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Shear strength tests investigated the effects of weld width and induction tempering temperature on the mechanical properties of the joint. Results indicate: The brazed joint formed a stable metallurgical bond with no visible cracks, though partial porosity existed within the weld. It exhibited a “65Mn steel-weld-YG6X cemented carbide” structural characteristic; Fe, Cu, Co, and other elements exhibited mutual diffusion at the interface; weld width significantly influenced joint strength, with shear strength increasing by approximately 27.2% when width decreased from 20 μm to 8 μm; Induction tempering temperature regulated weld shear strength, with optimal strength (161.3 MPa) achieved at 400°C tempering—a 20 MPa increase over untempered specimens. Beyond 500°C tempering, shear strength progressively declined below untempered levels.

     

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