Microstructure and fatigue properties of 17Cr2Ni2MoVNb gear steel after gas carburizing and low-pressure carburizing

In this work, the microstructure and fatigue properties of the 17Cr2Ni2MoVNb gear steel after gas carburizing (GC) and low-pressure carburizing (LPC) were comparatively evaluated. The results showed that fewer carbides and a higher fraction of retained austenite (RA) were found in the carburized layer of the LPC specimens, as a result of the different quenching temperature. Rotating bending fatigue tests revealed that both the LPC and GC specimens had a fatigue limit of 980 MPa. Compared with the GC specimens, the LPC specimens had significantly higher fatigue strengths at a specific number of cycles under high cyclic stresses.

Automated summary

The microstructure and fatigue properties of 17Cr2Ni2MoVNb gear steel after gas carburizing and low-pressure carburizing were compared and evaluated. The carburized layer of the low-pressure carburizing specimens had fewer carbides and a higher fraction of retained austenite due to the different quenching temperature. Both gas carburizing and low-pressure carburizing specimens exhibited a fatigue limit of 980 MPa. However, the low-pressure carburizing specimens showed significantly higher fatigue strengths at a specific number of cycles under high cyclic stresses compared to the gas carburizing specimens.