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 ...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 microstructure of brazing BNi-2 brazing coating is mainly CrB phase, Ni solid solution phase and eutectic phase of Ni_(3)B and Ni_(3)Si. 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 Ni_(3)Si 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 Ni_(3)Si grew and the hardness recovered, but the overall hardness distribution was still lower than the brazing one. The results 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.展开更多
基金Zhongyuan Leading Talents of Science and Technology Innovation(ZYQR20180030)Zhengzhou major Science and Technology Innovation Project(2019CXZX0065)Major Science and Technology Projects of Henan Province(191110210100)。
文摘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 microstructure of brazing BNi-2 brazing coating is mainly CrB phase, Ni solid solution phase and eutectic phase of Ni_(3)B and Ni_(3)Si. 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 Ni_(3)Si 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 Ni_(3)Si grew and the hardness recovered, but the overall hardness distribution was still lower than the brazing one. The results 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.
