Carbide Defect in High Speed Steel

The most important microstructure of high speed steel(HSS) is featured by the large number of carbides in it which have crucial effect on the quality and properties of HSS.High quality steels are those which have uniformly distributed,fine grained and regularly shaped carbides.However,these ideal conditions are not so easy.Several common defects of carbides in HSS W18Cr4V,W6Mo5Cr4V2,W9Mo3Cr4V and W2Mo9Cr4VCo8 are analyzed,such as inhomogeneous distribution of carbides,large sized and angular shaped carbides,microcrack carbides,adherence between carbides,and lack of secondary carbides.Necessary measures for avoiding these defects are discussed.