Mechanical, Tribologycal and Corrosion Behavior of the P20 Steel Surface Treated by Plasma Nitrited and Plasma Nitrocarburized

Abstract

P20 is the most widely used tool steel for plastic mold fabrication. Usually, the steel for mold are carburized, nitrided or coated when higher surface hardness and better wear resistance, oxidation and erosion are desirable. Together with the nitriding process, the nitrocarburization is considered the most promising engineering techniques to increase the surface hardness and wear resistance of the steels. The objective of this project is to evaluate and to compare the fatigue, microwear and corrosion behavior of the P20 steel with and without plasma surface treated in order to verify if the nitrocarburizing provides better results than nitrided treatment, traditionally realized in this material to service application. Therefore, the plasma nitriding treatment will be carried out in the studied material at 520oC and gas composition of 80% N2 and 20%H2, that is the treatment conventional conditions of this material used commercially. In the plasma nitrocarburization treatment, will be used a gas mixture of X N2 - Y H2 - Z CH4 (in which x, y and z are variables) at 520oC. Then, it will be determined a gas mixture ideal condition to the nitrocarburization treatment. The material with and without treatment will be characterized for metallography, surface hardness profile hardness and x-ray to determine the formed phase. Abrasive microwear, corrosion and fatigue tests will be carried out in the base material and treated materials by plasma nitriding and nitrocarburization. The tests results will be compared and it will be determine if the nitrocarburization treatment would be an alternative to the P20 use in the chlorinated polymer molds. (AU)