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Effect of post-welding heat treatment on the microstructure and properties of BNi-2 brazing coating was analyzed.The phase transformation in the heat treatment process was analyzed by high temperature metallographic microscope,scanning electron microscope and X-ray diffraction,and the microhardness after the post heat treatment was tested by microhardness tester.The results show that the micro-structure of brazing BNi-2 brazing coating is mainly CrB phase,Ni solid solution phase and eutectic phase of Ni3B and Ni3Si.After brazing,the overall hardness value is higher,generally higher than 510 HV,and the microhardness in some areas is higher than 700 HV.After quenching,the solid solution phase of Ni increased,and the eutectic phase of Ni and Ni3Si decreased,leading to the softening of the brazing coating,the area whose microhardness in the range of 342 HV-454 HV increased.After tempering the brazed coating samples,the eutectic phases of Ni and Ni3Si grew and the hardness recovered,but the overall hardness distribution was still lower than the brazing one.The res-ults of the brazing post-heat treatment test show that the post-welding heat treatment will bring adverse effects on the hardness distribution of the coating,which may affect the wear resistance of the coating.