Investigation on High Temperature Wear Behavior of a Newly Developed Hot-Work Tool Steel

Dry sliding wear tests were performed at room temperature, 200, 400, 500 and 600 ℃ on a new hot-work tool steel which was developed for special condition. Wear mechanism was determined by observing and analyzing the morphology of the worn surface and subsurface. In addition, the depth of strain hardened zone below wear track and wear behavior of the new steel were evaluated. The experimental results show that the wear rate firstly increased and then decreased and finally increased with the increasing temperature. Average friction coefficient decreased at first and increased subsequently. At room temperature and 200 ℃, fatigue wear prevailed due to inadequate tribo-oxide on the worn surface. A dense of oxide layer generated on worn surface and the thickness increased as the temperature was enhanced from 400 ℃ to 500 ℃。In this case, mild oxidative wear prevailed. At 600 ℃, wear rate rapidly increased with the oxide layer fracture and spalling on worn surface under the lasted experiment load, the wear mechanism was oxidative wear. An obvious strain hardening area generated in subsurface in the process of wear and the hardening effect firstly increased and then decreased with the increase of temperature.