The Effect of Vacuum-Carbosintering Heat Treatment on the Wear Behaviors of Pre-Alloyed Powder Metallurgy Steel Parts

Abstract This study investigated the effects of vacuum-carbosintering on the wear behaviors of pre-alloyed powder metallurgy (PM) steel parts. Sintering (S), S + vacuum carburizing (VC), S + VC + intercritical annealing (ICA), vacuum-carbosintering (VCS), and VCS + ICA heat treatment processes were applied to the specimens produced by using the warm pressing method. Then, characterization studies, wear tests, and hardness measurements were carried out on them. In the VCS heat treatment, a carbon concentration of 2.025 wt% C was provided to the specimens. This rate was 1.184 wt% C in the S + VC heat treatment. The carbon concentration decreased from the surface to the center and a carbon diffusion depth of about 2 mm was obtained. The S treatment had a surface hardness of 99.78 HV1.0, the S + VC treatment had a surface hardness of 520.71 HV1.0, and the VCS treatment had a surface hardness of 471.44 HV1.0. The ICA heat treatments increased the surface hardness of the specimens. The S heat treatment caused the highest volume loss and specific wear-rate in the specimens, which was followed by the VCS treatment. The S + VC and ICA heat treatments caused a low volume loss, a low specific wear-rate, and a low coefficient of friction (CoF) in the specimens. The S heat-treated specimens had the highest CoF value (0.437). The VC, VCS, and ICA heat treatments caused CoF values in the range of 0.238–0.264, and there was no significant difference between them.