Effect of Sulphide on Fatigue Crack Initiation of W6Mo5Cr4V2 Cold Ring-rolling Mandrel

There is plus-minus duplicity in the effect of sulplide inclusion on fatigue crack initiation.The effect of sulplide shapes,size,distribution and mechanical property on the fatigue fracture of high speed steel W6Mo5Cr4V2 cold ring-rolling mandrel is analyzed.It is considered that soft sulplide has some effects on brittle inclusion,such as encapsulation and buffering.These effects could slow up the mosaic stress of hard brittle non-metal inclusion to the matrix and inhibit the initiation of fatigue crack,however the inelusian still acts as rending to the matrix.