THE EFFECT OF THERMODIFFUSION BOROCHROMIZING ON THE STRUCTURE AND PROPERTIES OF AISI H12 AND ASTM L6 STEEL

10.25712/ASTU.1811-1416.2024.02.009

Abstract

The paper explores the extensive applications of AISI H12 and ASTM L6 tool steels in the industrial sector, along with their surface treatment requirements. To enhance the hardness and wear resistance of tool steels and address the insufficient bonding strength between boride layers and substrates, the paper proposes a boron-chromium saturation diffusion strengthening method. This method involves simultaneous infusion of boron and chromium to form a boron-chromium layer, improving the performance and bonding strength of boride layers while addressing their brittleness and low high-temperature oxidation resistance. The microstructure and high-temperature oxidation resistance of boride layers were studied using scanning electron microscopy (SEM). The results indicate that when the Cr₂O₃ content increases to 2 %, a dense structure forms in the diffusion layer, leading to thickness increases in AISI H12 and ASTM L6 tool steels to 55.4 μm and 33.4 μm, respectively, with ASTM L6 steel exhibiting notable high-temperature oxidation resistance. This study provides significant references and guidance for enhancing the performance and prolonging the service life of tool steels.