Friction and Reciprocating Wear Behavior of Borided AISI H13 Steel Under Dry and Lubricated Conditions

In this work, the tribological performance of borided and untreated AISI H13 steels under dry and lubricated conditions was studied. The formation of the boride layer on the AISI H13 steel was conducted using the powder-pack boriding process at 950 degrees C for 6 h of exposure. The tribological performance was studied by reciprocating sliding wear tests, conducted with an alumina ball establishing a sliding distance of 100 m and a speed of 30 mm s(-1). The normal loads in dry tests varied from 10 to 25 N, compared with the loads ranged from 75 to 150 N under lubricated conditions (SAE 10W-40). The results showed that under dry conditions, the coefficient of friction (COF) ranged between 0.59 and 0.68 for the borided AISI H13 steel, and from 0.64 to 0.71 for the untreated H13 steel; the wear rates, at 25 N, were estimated around of 0.8 x 10(-5) and similar to 6 x 10(-5) mm(3) N-1 m(-1), respectively. In contrast, using lubricant, the COF decreased to values from 0.10 to 0.11, for both materials, in which the wear rates decreased one order of magnitude. Finally, for the overall set of experimental conditions, failure mechanisms such as smearing, cracking, pitting and plastic deformation were identified.