Structure and Hardness of High C-Cr Roller Steel Treated by Laser Melting

Laser melting was performed on high-C high-Cr steel.The structure,phase composition and hardness of the high-Cr C steel after laser melting were studied by means of XRD,OM,SEM and EPMA.The results show that the laser melting led to the distribution improvement of net carbides and the refinement of grains.The structure of the melted zone consisted of equiaxed grains,dendrite and cellular grains from the surface to the bottom with austenite microstructure and a few carbides precipitated at grain boundaries.Convention resulted in uniform distribution of the alloying elements in the melted zone,but fine carbides rich in Cr,Mo,V elements precipitated along grain boundaries.Microhardness in melted zone was low due of the presence of a high volume fraction of austenite,but the highest hardness of the HAZ could reach 759 HV.