A Fe-Ni-Cr system filler metal for brazing of stainless steel

New Fe-Ni-Cr system brazing alloys were designed,in which elements Si and B as well as Cu-Ti binary alloy were added as the temperature depressants.The brazing alloys were fabricated into filler foils by a rapidly-solidifying technique.It was found that,to acquire a suitable liquidus temperature of the filler alloy,the addition of Cu-Ti binary alloy decreased the needed amount of Si and B,and it had an effect on improvement in mechanical properties of the brazed joints.Based on the results of melting and wettability experiments,one filler metal was used to join stainless steel at 1 140 ℃ for 15 min.The microstructure of the joint was analyzed by means of a scanning electron microscope（SEM） equipped with X-ray energydispersive spectroscopy（EDS）.It was found that the typical joint was mainly composed of solid solution with a small quantity of Cr-rich borides strips,Ti-rich boride blocks and Cu-rich silicide particles.The brazed joints show an average tensile strength of 210.8 MPa and an average impact toughness of 35.6 J/cm².