纯铝导体电阻钎焊工艺与接头性能

Resistance brazing technology and brazed joints’ properties of pure aluminum conductor

  • 摘要:
    目的 结合电机纯铝导体绕组用材质和接头结构型式,以及钎焊纯铝的固有特点,解决在大气中实现纯铝导体绕组电阻钎焊的技术难点。
    方法 以Zn-Al合金为金属皮、氟氯酸铯钎剂为药芯,与钎料制造厂家共同研制了药芯焊片。以药芯焊片为预置钎焊填充材料,药芯焊条为手工辅助钎焊填充材料,电阻钎焊为钎焊接头连接方法,进行钎焊试验。结合电机绕组用纯铝导体线规和产品结构特点,设计了纯铝导体的钎焊搭接接头,钎焊后进行了目视检测、宏观金相、维氏硬度、面钎着率、拉伸性能、直流电阻和通电温升等检测。
    结果 钎焊接头目视检测结果符合ISO 18279 B级要求,接头宏观金相线钎着率和接头搭接区面钎着率检测结果符合ISO 18279 B级大于等于80%的要求,接头钎缝的维氏硬度平均值为57.8 HV0.1,接头抗拉强度平均值60.59 MPa略低于母材抗拉强度平均值63.08 MPa,接头直流电阻平均值353.64 μΩ略低于母材直流电阻平均值354.93 μΩ,接头通电温升平均值117.2 ℃略低于母材通电温升平均值117.5 ℃。
    结论 采用0.3 mm Zn-Al药芯焊片作为预置钎焊填充材料、同材质\phi 2.0 mm药芯焊条作为外围辅助填充材料,可实现大气中电机绕组用纯铝导体的电阻钎焊,钎焊接头的综合性能可满足设计和工艺要求。

     

    Abstract: Objective Material and joint structure of pure aluminum conductor winding in motor, as well as inherent characteristics of brazing pure aluminum, were combined to solve technical difficulties of resistance brazing of pure aluminum conductor in atmosphere. Methods Taking Zn-Al alloy as metal skin and cesium fluochlorate as flux core, brazing flux-cored piece was developed jointly with brazing material manufacturers. Taking brazing flux-cored piece as the prefabricated filler material, brazing flux-cored bar as the manual auxiliary filler material and resistance brazing as a joint connection method, brazing experiment was carried out. According to conductor size of pure aluminum conductor used in motor winding and characteristics of product structure, brazed joints of pure aluminum conductor were designed. After brazing, visual test, macroscopic metallography, Vickers hardness, surface brazing rate, tensile properties, DC resistance and current temperature rise were measured. Results Visual test results of brazed joints met requirements of ISO 18279 B. Test results of joints’ line brazing rate in macroscopic metallography and area surface brazing rate of joints’ lap area met requirements of ISO 18279 B greater than or equal to 80%. Average Vickers hardness of brazed joints was 57.8 HV0.1. Average tensile strength of brazed joints was 60.59 MPa, which was slightly lower than that of base material 63.08 MPa. Average DC resistance of brazed joints was 353.64 μΩ, which was slightly lower than that of base material 354.93 μΩ. Average current temperature rise of brazed joints was 117.2 ℃, which was slightly lower than that of base material 117.5 ℃. Conclusion Resistance brazing of pure aluminum conductor for motor winding in atmosphere could be realized by using 0.3 mm Zn-Al flux-cored brazing piece as the prefabricated filler material and \phi 2.0 mm flux-cored bar as the peripheral filler material. Comprehensive properties of brazed joints could meet the design and process requirements.

     

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