OBSERVATIONS ON WEAR OF HIGH-HARDNESS STEELS

Laboratory experiences on wear of several types of high-hardness steels are discussed. The discussions are based on the results and observations obtained in crossed-cylinder wear testing. The microconstituents present in the steel have decisive effects on the wear behavior. The nature of the second phases-carbides or intermetallic compounds-is of key importance in this regard. The amount of MC-type carbides is the prevalent factor in high speed steels; the size of primary carbides is also shown to influence the wear behavior. The wear rate of D2 die steel is reduced by continuous removal of loose debris. The debris consists mainly of oxides, but the presence of Cr7C3 carbide is also evident. Light and electronmicroscopic examinations of wear surfaces allow the observation and interpretation of the actual wear process. Gradual wear of the primary carbides in D2 die steel is indicated, and marked differences in the surface appearances of D2 and A2 die steels are observed. © 1969.