DESGASTE E ATRITO DA CAMADA NITRETADA DO AÇO ABNT H13 NITRETADO POR PLASMA PULSADO

Abstract

ABNT H13 tool steel discs were nitrided by pulsed plasma in an atmosphere 20% N 2 and 80% H 2 at a temperature of 400oC in different times: 1 h, 4 h, 9 h, 16 h and 36 h. The discs were tested in a tribometer in order to study the sliding wear of the nitrided material. A sphere of Si 3 N 4 with a diameter of 7.14 mm was used. A normal load of 800 N was applied. The discs slid under the sphere without lubricant for 8 h at a sliding speed of 0.05 ms -1 up to reach a total distance of 1.440 m. The results show that longer nitriding times reduce the volume of wear. The following wear mechanisms are observed: plastic deformation, ploughing and spalling. These mechanisms are correlated to the microstructure of the nitrided layer. The friction coefficient is 0.2 for all tested conditions.