Fabrication methods and heat treatment conditions effect on tribological properties of high speed steels

Investigations carried out in this work reveal that the experimental high speed steels of the HS6-5-2 and HS12-1-5-5 types pressureless formed from the polymer-powder slurry and heat treated are characteristic of the high abrasion wear resistance. These steels can be austenitized at a lower temperature compared to the commercial steels, because of the high concentration of carbon remaining after the binder degradation, lowering the solidus temperature. Tribological tests of the experimental steels confirm the sense of employing the pressureless high speed steel forming from the polymer-powder slurry, and especially their sintering in the protective gases atmosphere N₂-5% H₂, due to which nitrogen diffusion occurs and fine carbonitrides of the MX type develop, improving abrasion wear resistance of these steels. The HS12-1-5-5 grade experimental steel made by pressureless forming from the polymer-powder slurry, for which the material volumes removed during the pin-on-disc and pin-on-plate tests are about 0.01 and 0.005 mm₃, respectively, is characteristic of the highest abrasive wear resistance.