Research On Brazing Technology Of Cermets And Steel

Ti(C,N) based cermets and Mo2FeB2 based cermets were brazed to 45 steel with Cu based filler in this dissertation, the effect of brazing parameters on shear strength of joints have been studied, the interface product, microstructure and distribution of element across brazing joints have been investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive X-ray analysis(EDS).The development and application of cermets have been reviewed, the research development of connection technology for 20 years have been overviewed, the advantages and disadvantages of various connection technologies have been introduced, varieties of brazing technology and filler have been compared each other, the purpose and significance of this dissertation were introduced based on the contrast.Ti(C,N) based cermets was brazed to 45 steel, with Cu based filler made by ourselves. The effect of brazing parameters on shear strength and microstructure of joints have been studied. The optimal technological parameters were 1060 ℃ and 10 min, the highest shear strength of joints reached 195.3MPa, a certain thickness of diffusion layer have been formed at the interface, the phase were mainly(Cu,Ni)、(Fe,Ni) solid solution.The vacuum brazing of Mo2FeB2 based cermets and 45 steel have been studied for the first time, with the Cu based filler. The effect of brazing parameters on shear strength exhibited parabolic, when the technological parameters were 1020℃ and 15 min, the highest shear strength of joints reached 240.5MPa, the binder diffused from cermets to filler, decreasing the strength of cermets and inhibiting the diffusion of the elements of filler, which resulted to decrease the shear strength of joints at last.Cu based filler with multi-elements alloy have been developed, based on the origin filler, the shear strength of Mo2FeB2 and Ti(C,N) based cermets and 45 steel were increased to 270.4 MPa and 275.7 MPa, with the Cu based filler with multi-elements alloy as filler, the optimal brazing temperature were both increased by 20℃ accordingly. The diffuse reaction was improved, with content of elements changing, as a result, shear strength and temperature of brazing joint were enhanced, the brazing mechanism have been researched at last.