Investigation of high temperature dry sliding behavior of borided H13 hot work tool steel with nanoboron powder

摘要

Boride layer characterization and dry sliding wear behaviors of bonded H13 steel at different durations and temperatures with nanoboron powder have been investigated. A single phase boride layer was formed at 800 degrees C and a double phase boride layer was obtained at 900 degrees C and 1000 degrees C. According to the bonding process with Ekabor II, higher ratio FeB/FeB + Fe2B and total boride layer were formed when nanoboron was used in the bonding process. It has been observed that the increment in the bonding temperature and bonding duration has increased the boride layer thickness from 6,34 mu m to 103.26 mu m. Manganese boride and chromium boride phases were determined along with iron borides in the boride layer. The hardnesses of borides formed on the H13 steel reached 2028 HV(0.1 )and the change in hardness from the surface to the interior was slower at samples which were bonded at higher temperatures and durations. Fracture toughness was found to be in the range of 1.32-5.23 MPa-m(1/2) depending on boronizing time in samples which were bonded at 1000 degrees C. The increase in the bonding temperature and bonding duration led to increased wear resistance. At high temperature, microcrack-induced plastic deformation and fatigue; at room temperature, microcrack formation were dominant wear mechanisms.