Microstructure and mechanical behavior of AISI 8620 steel subjected to solid-state boriding

Boriding is a thermochemical surface treatment widely applied to steels to enhance hardness and wear resistance. However, the relationship between boriding parameters and mechanical performance under bending stresses remains insufficiently explored. This study evaluates the influence of boriding time on the microstructural evolution and mechanical behavior of AISI 8620 steel. Solid-state boriding was performed at 950 °C for 2, 4, 6, and 8 h, followed by microstructural characterization and mechanical testing. The results revealed a progressive increase in boride layer thickness from approximately 100 µm–170 µm and a significant improvement in surface hardness, reaching values above 2,000 H V. Flexural strength exhibited optimal performance for samples treated for 4 and 8 h, indicating a balance between hardness and toughness. These findings provide an integrated understanding of how boriding time affects both surface and bulk properties, offering practical guidelines for optimizing treatment conditions in components subjected to combined wear and mechanical loads.