Effect of solidification rate on the morphology and distribution of eutectic carbides in centrifugal casting high-speed steel rolls

The morphology and distribution of the eutectic carbides has an important influence on the properties of high-speed steel (HSS) rolls. Manufacturing methods reported previously have not achieved effective refinement and dispersal of the eutectic carbides. In order to investigate the effect of the solidification rate (SR) on the eutectic carbides and find a way to refine them, the morphology and distribution of the carbides has been studied systematically under various solidification rates, which were controlled by using different moulds with several initial temperatures. The morphology and distribution of the eutectic carbides was assessed by optical microscopy (OM) and scanning electron microscopy (SEM), as well as by X-ray diffraction (XRD) and X-ray energy dispersive spectrum (EDS). It was found that, with the increase of SR, the eutectic carbides became finer and more uniformly dispersed. A high SR can be recommended as a good way to improve the wear resistance and thermal fatigue properties of high-speed steel rolls.