Investigation of tribological behaviour of plasma paste boronized of AISI 8620, 52100 and 440C steels

Abstract

370-376In the present study, AISI 8620, 52100 and 440C steels were plasma paste boronized (PPB) by using 100% borax paste. PPB process was carried out in a dc plasma system at temperature of 700 and 800<span style="font-family:Symbol; mso-ascii-font-family:" times="" new="" roman";mso-hansi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-US">°C for 3 and 5 h in a gas mixture of 70%H2-30%Ar under a constant pressure of 4 mbar. Wear tests of the bearing steels were performed using a ball-on-disc test device. The applied loads on the ball were 5 and 20 N and the sliding time was 60 min for each test. Wear tests were carried out in the unlubricated and lubrication conditions at room temperature in air. Wear volume of the disc specimen was determined from the cross-sectional area of the wear track, obtained perpendicularly to the sliding direction. Worn surfaces of the samples were PPB characterized by scanning electron microscopy and the results were compared with those obtained for plasma paste boronized specimens. </span