【摘要】 冷却废气再循环(EGR)系统可以有效降低汽车尾气中NOx的排放,核心部件EGR冷却器一般采用真空钎焊工艺制造。综述了应用于真空钎焊不锈钢EGR冷却器的高温钎料的研究进展,分析镍基、铜基钎料以及新型铁基钎料的优缺点,重点介绍新型铁基钎料的研究进展。分析钎料合金元素对钎料熔融温度、钎缝组织及钎焊接头力学性能的影响,阐述钎焊工艺对不锈钢母材溶蚀和钎缝组织的影响规律,并对不锈钢高温钎料的未来研究方向和发展趋势进行了展望。更多还原

【Abstract】 The cooled exhaust gas recirculation(EGR) system can effectively reduce the NOx emissions in the vehicle exhaust. The EGR cooler is the core component of the cold EGR system and is vacuum brazed. The research progress of high temperature brazing filler metal for vacuum brazing stainless steel EGR cooler is reviewed. The advantages and disadvantages of traditional nickel-based,copper-based brazing filler metals and new iron-based brazing filler metal are analyzed. The new iron-based brazing filler metal is mainly introduced. The effects of brazing filler metal alloy elements on melting temperature,microstructure and mechanical properties of brazing joint are analyzed. The influence rule of brazing technology on the corrosion of stainless steel base metal and the microstructure of brazing joints is introduced emphatically. And future research direction and development trend of high temperature brazing filler metal for stainless steel are prospected.更多还原