Brazing Process And Bonding Mechanism Of0Cr18Ni9Steel Brazed With BNi-2Filler And1Cr11Ni2W2MoV Steel Brazed With Cu58MnCo Filler

0Cr18Ni9stainless steel has fine intensity of low temperature, favorableresistance to corrosion and heat, so that it can be applied to the manufacture of thefuel injector of the airspace or aircraft engine.1Cr11Ni2W2MoV stainless steel hasboth high strength and tenacity, as well as excellent resistance to corrosion, heat andfatigue, so that it can be used to manufacture the vanes in casing of the airspace oraircraft engine. So the research on bonding the same base metal of this two kinds ofsteel has great value on applications. The project researches influence of variationsof brazing parameters on the organization and performance of joints by the methodof controling variate. The optimal brazing process is summarized and the bondingmechanisms of this two kinds of joints are analyzed by the means of SEM, EDS andXRD.0Cr18Ni9-0Cr18Ni9joints brazed with BNi-2filler metal consist of the basemetal of0Cr18Ni9stainless steel, interfacial region and filler alloy. Rising ofbrazing temperature and extending of holding time can both suppress the formationof cracks and compounds in the filler alloy. Diminishing of brazing seam width canmake it easier for B and Si element to diffuse adequately, and lead to reduction ofcracks and compounds in the filler alloy. Slowing down the cooling speed canpromote the diffusion of B and Si element and suppress the formation of cracks.Rising of gas pressure of brazing environment can promote the interdiffusion ofelements in joints so that the organization of joints become more homogeneous. Allthe0Cr18Ni9-0Cr18Ni9joints failure in matrix, which means, the bondingstrength of joints is higher than the strength of the original0Cr18Ni9steel so thatthe brazing process can be appplied to practical products. The project selects1050℃,10min,10μm,15℃/min and10-2Pa as the optimal brazing parameter forthe0Cr18Ni9-0Cr18Ni9joint brazed with BNi-2filler metal, and brazed theemulational fuel injector successfully.1Cr11Ni2W2MoV-1Cr11Ni2W2MoV brazed with Cu58MnCo filler metalconsist of the base metal of1Cr11Ni2W2MoV stainless steel, diffusion zone, filleralloy. Rising of the brazing temperature and extending of the holding time candecrease the atomic percentage of the Mn element in the filler alloy, so that thesheer strength of joints deteriorate, Although the wider brazing seam results in thehigher concentration of Mn element in the filler alloy, the higher proportion ofCu[Mn] which is regarded as the weaker organization can deteriorate theperformance of the joint as the dominant factor. For vacuum brazing, using the process of990℃,10min,30μm can obtain the joint whose sheer strength is309MPa.The joint brazed in the atmosphere of argon has the higher strength than that of thejoint brazed in vacuum.990℃,10min,50μm, the average sheer strength of the jointbrazed in the atmosphere of argon achieves363MPa. The project selects990℃,10min,30μm and argon atmosphere as the optimal brazing parameter for the1Cr11Ni2W2MoV-1Cr11Ni2W2MoV brazed with Cu58MnCo filler metal.