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钎焊材料预处理及烧结气氛对铁基粉末冶金零件烧结钎焊的影响

Effect of brazing material pretreatment and sintering atmosphere on sinter-brazing of iron based powder metallurgy parts

  • 摘要: 采用水雾化Ancorbraze 72(AB72)粉为钎焊料,对铁基粉末冶金材料进行烧结钎焊。通过钎焊料预处理和改变烧结气氛研究钎焊料润湿性及其在母体材料中的渗入深度。结果表明:随着钎焊料预处理温度的上升,钎焊料在母体表面残留物的最大直径明显减少,钎焊料在距离润湿面1000 μm处的扩散范围逐渐降低。当预处理温度为800 ℃时,钎焊料残留物最少,距润湿面1000 μm处扩散范围最小,预处理效果最好。当预处理温度为800 ℃,处理时间长度为2 h,处理气氛为75%N2+25%H2(体积分数)时,烧结钎焊后钎焊料表面残留较少,距润湿面1000 μm处钎焊料的扩散范围最小。烧结钎焊时通入一定量的吸热性气氛可以明显改善钎焊料在基体中的渗入情况,当通入吸热性气氛流量为20 m3∙h−1时,对润湿角和渗入深度的改善效果最好。

     

    Abstract: The iron-based powder metallurgy materials were sintered and brazed with the water atomized Ancorbraze 72 (AB72) powders. The wettability and penetration depth of the brazing materials were studied by brazing material pretreatment and changing sintering atmosphere. The results show that, with the increase of pretreatment temperature, the maximum diameter of brazing residue on the matrix surface decreases obviously, and the diffusion range of brazing material at 1000 μm away from the wetting surface decreases gradually. When the pretreatment temperature is 800 ℃, the brazing residue is the least, the diffusion range is the least at 1000 μm away from the wetting surface, and the pretreatment effect is the best. When the pretreatment temperature is 800 ℃, the treatment time is 2 h, and the treatment atmosphere is 75%N2+25%H2 (volume fraction), the residue on the brazing surface is less, and the diffusion range of the brazing materials is the smallest at 1000 μm away from the wetting surface. A certain amount of endothermic atmosphere during the sintering brazing can obviously improve the penetration of brazing materials in the matrix. When the flow rate of endothermic atmosphere is 20 m3∙h−1, the improvement of wetting angle and penetration depth is the best.

     

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