Microstructure characterization and high-temperature wear behavior of plasma nitriding mold steel

Considering the cyclic variation of temperature and load in the glass molding, the mechanical properties and wear behavior of the nitriding mold steel at high temperatures are necessary to investigate. In this research, the microhardness variation of mold steel after plasma nitriding is elucidated and associated with the microstructure. The high-temperature nanoindentation experiments are conducted to clarify the impact of temperature on mechanical behavior of the nitriding steel. The hardness and elastic modulus of the nitriding steel are decreased by 40.9 % and 19.5 % when the temperature increased from room temperature to 400 °C. Correspondingly, due to the hardness dropping, the wear resistance of the nitriding mold steel decreases gradually with the temperature. However, the wear resistance of the nitriding mold steel under high temperatures is still superior to that of conventional mold steel. A wear schematic model is developed to elucidate the wear behavior evolution mechanism of the nitriding steel with temperatures. This work provides a comprehensive investigation of the mechanical and wear behavior of the nitriding mold steel under high temperatures which avoids mold wear failure in glass compressing molding.