Influence of plasma nitriding pressure on microabrasive wear resistance of a microalloyed steel

• Main Authors: Henver Effgen Ludovico Ramos, Adonias Ribeiro Franco, Jr., Estéfano Aparecido Vieira
• Format: Article
• Language: English
• Published: Elsevier 2019-04-01
• Series: Journal of Materials Research and Technology
• Online Access: http://www.sciencedirect.com/science/article/pii/S223878541730892X

Microalloyed steels have been studied not only by the advent of the pre-salt, but also by the continuous search for improvement of their tribological properties. In this work, the influence of the plasma nitriding (PN) pressure on the nitrided layer formed on top of an API 5L X70 microalloyed steel was studied. PN treatments were carried out using a pulsed plasma reactor at temperatures of 410 °C and 440 °C, in a gas mixture of N2 and H2, for 3 h and under different pressures. Results showed that the pressure has a significant effect on the uniformity and width of the plasma sheath and, consequently, on the structure and thickness of the resulting nitrided layer. It has been observed that higher pressures and temperatures have led to the formation of nitrided layers containing a thinner white layer and without nitride needles. The best wear results were offered by the thicker nitrided layers, besides thinner white layer. This type of structure can be produced when PN treatments are performed using low-width plasma sheaths. Keywords: Plasma nitriding, API 5L X70 microalloyed steel, Pressure, Plasma sheath, Micro-abrasive wear resistance