Metallographic characterisation of 2205 duplex stainless steel brazed joint

摘要

Based on that shown one can conclude that: a) In the BNi-1 and BNi-2 fillers, an austenitic phase was formed, Ni-a, a Ni-Fe-Cr-Si compound in the interface between the base metal and filler metal. Whilst the BNi-7 formed an Ni-Fe-Cr austenitic phase. When this phase is continual as in the case of the ideal gap of a brazed joint, the joint properties are superior to those of the base metal. In the case of non-ideal gaps, the joints formed phases with a high level of hardness at the centre of the joint, deteriorating its mechanical and corrosion properties in all the filler metals studied. Due to the high C and B content of the BNi-1 alloy, Fe, Cr and Mo boron carbides were formed when the gap is larger than the ideal joint gap. All three alloys caused the formation of an intermetallic phase in the base metal close to the transition joint/base metal. This indicates that brazing conditions are not adequate for 2205 duplex stainless steel.