Variation of wear behavior of H13 steel sliding against different-hardness counterfaces

Dry sliding tests for H13 steels sliding against different-hardness counterfaces were performed in air under a load of 50–300 N at 25–600 ℃ on a pin-on-disk elevated temperature tester. The hardness of the counterface was noticed to appreciably affect the wear behavior of H13 steel. When H13 steel slid against a hard counterface (55 HRC), the wear rate increased with an increase of temperature. As the load increased, the wear rate marginally increased at 25 ℃ and 200 ℃ but rapidly increased at 400 ℃ and 600 ℃. When H13 steel slid against a softer counterface (42 HRC), the wear rate roughly decreased with an increase of temperature besides 600 ℃. As the load increased, the wear rate rapidly increased at 25 ℃ but slightly increased at 200 ℃, 400 ℃ and 600 ℃. The large variation of the wear behavior of H13 steel was attributed to the competition of the wear-reduced function and the delamination of tribo-oxide layers. At elevated temperature, the tribo-oxide layer readily delaminated under the abrasive action of the hard counterface; conversely, it stably stayed on worn surfaces to take a wear-reduced function for the soft counterface. Adhesive wear prevailed for the hard counterface at 25–200 ℃ and the soft counterface at 25 ℃. For the soft counterface at 200–600 ℃, oxidative mild wear prevailed, but for the hard counterface, at 400–600 ℃, a mild-to-severe wear transition of oxidative wear occurred.