Surface Hardening Behavior of Advanced Gear Steel C61 by a Novel Solid-Solution Carburizing Process

During vacuum carburizing, coarse reticulated carbides tend to precipitate along grain boundaries due high-carbon-potential conditions. This phenomenon is often one of the main factors in failure conventional gear steels. In this paper, a novel solid-solution carburizing process was proposed achieve nano-carbide formation surface layer, and material thermodynamic calculations were combined study carburized layer by changing parameters process, optimize microstructure properties layer. The results showed that high carbon potential or long-time boost could easily cause enrichment many atoms traditional carburization, thus forming carbide network decreasing carburization efficiency. minor increase large-sized M7C3 did not significantly improve hardness wear resistance. However, presence small dispersed M2C factor improving microhardness mechanical properties. efficiency transform into nano-dispersed carbides. content 1.07% 875 HV, respectively, increased 17.7 2.4% compared processes at 1100 °C. On other hand, surface’s ultimate tensile strength found be 1900 MPa mini-tensile testing, core had good match toughness. It concluded dissolve effectively content, achieving fully nanosized on surface. Modifying size, morphology, distribution nano-M2C within lath-martensite after tempering test steel