Development Of Powder Core Material For Surface Arc Spraying Used On Hot Working Die

Aiming at solving the failure of hot forging die in service,such as localized wear and thermal fatigue cracking,three kinds of alloy powder core spraying material,FeCrNiAl,FeBSiCrAlNi and FeCrMoBSiAlNi,were designed and manufactured.A series of test coatings were prepared on 5CrNi Moby using high-speed arc spraying technology.According to the results,no obvious appearance defects were found in the coating samples except for the poor bonding degree between FeCrNiAlcoating and substrate.The structures,composition and properties of the coatings were studied by means of OM,SEM,EDS,XRD,Vickers Indenter and Friction/Wear Machine.In addition,the effect of hot pressing deformation on the structures and properties of the coatings was preliminarily explored by using a four-high reversible plate mill.The results show that all coatings show typical layered inhomogeneous structures,with a large number of pores and unmelted structures.?-Fe,Fe-Cr,Ni-Cr-Feand intermetallic compounds of Ni with Aland Feare the main phases found in the coatings,containing a small amount of Cr₂O₃,Al₂O₃.The average microhardness of FeBSiCrAlNi coatings reaches 864.56 HV0.2,and the lowest is 682.17 HV0.2 after increasing the content of Ni element in FeBSiCrAlNi,respectively,which are higher than those of the substrate.The coating exhibits good thermal shock resistance,which is superior to the substrate in high temperature oxidation resistance,friction and wear resistance and high temperature erosion resistance.With the increase of Ni content,the density of FeCrMoBSiAlNi coating increases and the chemical micro-inhomogeneity coefficient decreases and the highest number of thermal shock is 116 and the high temperature oxidation resistance is superior to the substrate.Friction and wear test shows that the friction coefficients of the coatings fluctuate less than substrate.The weight loss rates of friction and wear are less than 50%of the substrate,and the erosion weight loss rates of coatings at high temperature are less than substrate.Among them,the friction and wear weight loss of the FeCrMoBSiAlNi coating with high Ni content is the lowest of 0.08%and the erosion weight loss at high temperature is the lowest which is only 24.7%of the substrate.The hot-pressing deformation test of the coating shows that the density and microhardness of coatings can be obviously improved by a certain amount of deformation at 450?.The density of coatings with high alloying degree and good plasticity increases obviously.