Study On Preparation And Grinding Performance Of Grinding Tool For Sintered Slide Gate

As the core part of the slide nozzle used in continuous casting steelmaking,the main function of sintered slide gate is to control the flow of molten steel during the continuous casting process.Sintered corundum-zirconia-graphite slide gate was wildly used because of its high strength,erosion resistance,and good thermal shock stability.The uneven sliding surface of the sliding will cause steel leakage.In order to obtain a sliding with a flat surface,it was necessary to use a diamond abrasive tool to grind the sliding suface.So that the sliding could reach the shape accuracy and flatness that meet the requirements of use.The characteristics of diamond tools and grinding parameters directly affect the grinding efficiency and the surface quality during the grinding process.The properties of hard brittle materials such as single crystal silicon wafers,engineering ceramics,and integrated circuits was studied by many scholars.A few of studies have been performed on the grinding performance of refractory materials such as slide gate,fused zircon corundum,and functional ceramics.Therefore,it was a great significance to investigate the characteristics of sintered slide gate and grinding performance of diamond tools for guiding the actual production.In this paper,the preparation and grinding performance of grinding tools for sintered slide gate were studied.A kind of metal-bonded diamond tool for grinding sintered slide gate was prepared,in order to improve the performance of diamond tools.Fe-based matrix,diamond segment and Fe-based bond diamond tools were prepared by hot pressing sintering.The effects of Ni mass fraction on the mechanical properties of the matrix and the diamond segment,the bonding strength between the matrix and diamond,the micro morphology of the matrix,and the phase composition of the matrix were studied.In addition,the performance difference between the matrixs that were prepared with elemental powder and pre-alloyed powder were compared.Besides,diamond tools for grinding sintered slide gate were prepared and its grinding performance were tested.The main conclusions are as follows:(1)With the increase of Ni mass fraction,the hardness,bending strength,and density of the matrix of the Fe-based binder matrix was increased.Bending strength and the holding force coefficient of the diamond segment increased first and then decreased,moreover,the maximum value appears when the Ni content is 12%.The cleavage surface on the fracture of the Fe-based matrix became smaller,the number of dimples gradually increased,and the fracture mode was mainly ductile fracture.The main phases of the matrix were?-Fe phase,?(Fe,Ni)phase,Cu₄₁Sn₁₁ solid solution and Cu₃Sn phase.The content of?(Fe,Ni)solid solution increased with the Ni mass fraction increased.The mechanical properties of the matrix samples prepared by pre-alloyed powder are better than those prepared by elemental powder,but the control of diamond is poor.(2)The grinding ratio of diamond tools increased first and then decreased,with the increase of Ni mass fraction.When the Ni mass fraction was 12%,the maximum grinding ratio was 200.79.The sharpness of different diamond tools decreased with the increase of the feed speed,meanwhile,and the sharpness of different diamond tools decreased with the grinding depth increased.Under the same working conditions,the sharpness of diamond grinding tools which were prepared with different Ni contents increased first and then decreased with the increase of Ni content.Among them,the sharpness of diamond tools was best when the Ni content was between 8%and 12%.(3)It can be seen from the microscopic morphology of the diamond and the matrix on the diamond tool that the diamond tail support gradually becomes wider and longer with the Ni mass fraction increases,and the height of the diamond cutting edge gradually increases from the scanning electron microscope's micro-morphology of the diamond tools after a period of used.When the Ni content was between 12%and 16%,the edges height was better.The sharper diamond tools had a higher diamond edge rate and a lower drop rate during grinding.