油冷器法兰板真空钎焊溢料问题分析和改善

Analysis and Improvement of Overflow in Vacuum Brazing of Oil Cooler Flange Plate

以油冷器法兰板用3003/6063/3003三层铝合金复合材料为研究对象,采用金相显微镜和扫描电子显微镜对真空钎焊后形成的溢料缺陷进行宏观形貌、显微组织观察,并和正常区域进行对比。通过优化材料的生产工艺,对溢料问题进行改善,并对效果进行验证。结果表明:油冷器法兰板真空钎焊后产生溢料主要是因为钎焊过程中熔化后的焊料发生了流动,在法兰板冲压孔附近表面形成了堆积;材料冷轧后进行中间退火,材料的总变形储能减小,成品退火时再结晶过程驱动力减小,有利于晶粒的长大;材料晶粒尺寸增大,钎焊后溢料有明显改善,主要是因为晶粒增大后,晶界的数量相应减少,钎焊过程中法兰板表面的焊料流动和堆积减少。

Taking 3003/6063/3003 three-layer Al alloy composite for oil cooler flange plate as the research object,the morphology and microstructure of the overflow defects formed after vacuum brazing were observed by metallographic microscope and scanning electron microscope,and compared with the normal area.Through optimizing the production process of materials,the overflow problem is improved and the effect is verified.The results show that the overflow of oil cooler flange plate after vacuum brazing is mainly due to the flow of melted solder during brazing,which forms accumulation on the surface near the stamping hole of flange plate.The material is intermediate annealed after cold rolling,the total deformation energy storage of the material is reduced,and the driving force of recrystallization process is reduced,which is conducive to the increase of grain size.With the increase of the grain size of the material,the overflow after brazing is obviously improved.The main reason is that the amount of grain boundary is decreased with the increase of grain size,and the solder flow and accumulation on the surface of flange plate are decreased during brazing.