Research On The Control Of Carbide And Inclusions In 8Cr13MoV Steel By Rare Earth Ce

8Cr13MoV steel is a kind of advanced martensitic stainless steels.It has been increasingly applied as high-grade cutter,valve,structural part,due to their high strength,hardness,excellent corrosion resistance and wear resistance.Especially in the production of high quality knives and scissors occupies a large proportion,but with the improvement of people's quality of life,The demand is gradually increasing for high-grade knife and shear products,therefore,the quality of knife and scissors products is placed in higher requirements.In this paper,based on the comprehensive properties of8Cr13MoV steel,The mechanism of modification of carbide and inclusion in8Cr13MoV steel with different content of rare earth Ce was explored.And the optimization results of microstructure and properties under the appropriate addition amount of rare earth.The conclusions was described as below.The microstructure observation of as-cast 8Cr13MoV steel shows that after adding rare earth,it will lead to refine grain.The microstructure is still austenite and martensite.Martensite transformation temperature decreased.The number of high-angle boundaries increased significantly.The number of small Angle grain boundaries decreased significantly.Meanwhile,when the Ce content was 0.14%,the segregation of carbide elements is inhibited,the number of carbide precipitates decreased from 876to 475,and the area of carbide precipitates decreased from 939?m² to 801?m² the carbide evenly distributed in steel.The increase of Ce content made the morphology of carbides change from large composite rod morphology into single lamellar morphology.The content of O and S in steel decreased significantly with the increase of the content of Ce,the purification effect of molten steel is obvious.Inclusions existing in steel without Ce are mainly Al₂O₃,MnS and Si-O-S-Mn composite inclusions,the shape of the inclusions is irregular and the size of 2?10?m.After adding Ce,the inclusions are modified into Ce₂O₃,AlCeO₃ and Ce₂O₂S.When the Ce content was 0.14%,the average size of inclusions in steel is reduced.When the Ce content was 0.64%,larger rare earth inclusions are formed.The formation of rare earth inclusions was calculated by thermodynamic.At 1873K,the inclusions of Ce₂O₃,Ce₂O₂S were stable existed in steel.the thermodynamic calculation results were consistent with the observation results of scanning electron microscope.The properties of steel before and after adding rare earth elements were detected,When the Ce content was 0.14%,the hardness is increased from 45 HRC to 48 HRC,the yield strength of the steel increases 78 MPa,the tensile strength increases 99 MPa and the elongation increases 1.2%.The self-corrosion potential of steel was increased,the anode current density was decreased,and the corrosion resistance of steel was improved.