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单层高温钎焊超硬磨料砂轮具有传统电镀砂轮无法比拟的优异磨削性能 ,国内应及早研制开发应用此种砂轮。本文利用真空炉中钎焊的方法 ,用Ni Cr合金钎料 ,适当控制钎焊温度、保温时间和冷却速度 ,实现了金刚石与钢基体间的高强度连接。扫描电镜X射线能谱 ,结合金相及试样逐层的X射线结构分析 ,剖析了Ni Cr合金与金刚石和钢基体钎焊界面的微区组织结构 ;揭示了Ni Cr合金对金刚石和钢基体表面的浸润和钎焊机理。即在钎焊过程中会在金刚石界面形成富Cr层并与金刚石表面的C元素反应生成Cr7C3,在钢基体结合界面上Ni Cr合金和钢基体中的元素相互扩散形成冶金结合 ,这是实现合金层与金刚石和钢基体都有高结合强度的主要因素。最后重负荷磨削试验表明金刚石为正常磨损 ,没有整颗金刚石脱落 ,说明金刚石确有高的把持强度
Single-layer high-temperature brazing superabrasive grinding wheel with traditional electroplated grinding wheel can not be compared to the excellent grinding performance, the domestic should be the early development and application of such grinding wheel. In this paper, the use of vacuum furnace brazing method, with Ni Cr alloy brazing filler metal, brazing temperature, holding time and cooling rate, the realization of the high strength steel and steel matrix connection. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to analyze the micro-structure of the interface between NiCr alloy and diamond and steel substrate. The effects of NiCr alloy on the microstructure of diamond and steel substrate Surface wetting and brazing mechanism. In the process of brazing, a Cr-rich layer is formed on the diamond interface and reacts with the C element on the surface of the diamond to form Cr7C3. The elements in the Ni-Cr alloy and the steel matrix interdiffuse form a metallurgical bond at the steel substrate interface, Layer and diamond and steel substrates have a high bond strength of the main factors. Finally, heavy-duty grinding test showed that the normal wear of diamond, not the whole diamond off, indicating that the diamond does have a high holding strength