Effect of RE-Mg Complex Modifier on Structure and Performance of High Speed Steel Roll

The effects of rare earth (RE) and magnesium complex modifier on the structures and performance of high speed steel (HSS) roll were investigated and the mechanism of modification was analyzed by means of optical microscope (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) analysis, tensile testing machine and impact tester. The results showed that RE-Mg complex modifier could refine the grain, change carbide morphology and distribution, and increase mechanical properties. After heat treatment at 1000 °C, many networked carbides in HSS roll were broken and a number of granular carbides appeared. Most of eutectic carbides were spheroidized and distributed uniformly. The networked carbides disappeared completely after heated to 1050 °C. The reason that RE-Mg improves the microstructure of HSS roll was analyzed.