Surface Nitriding Response of Alloys J120V and J160
February 15th, 2024
C Paul Qiao, Joe Schreiner, Levi Kempka, Dominic Grillo
L.E. Jones Company
Menominee, MI 49858
Ferritic nitrocarburizing process have been widely adopted for surface nitriding J120V and J160 alloys commonly used for engine valve seat insert applications. While J120V is an M2 similar tool steel, J160 is an iron-based corrosion and wear resistant alloy. The difference in nitrided surface structures from these two substrate materials was investigated to correlate their service performance as engine valvetrain component. With J160 substrate, formation of surface compound zone can be practically controlled. Hence, nitrided J160 can have nitrogen/carbon situated diffusion zone surface layer alone or combined with a compound zone. For a specific application, with or without compound zone formation can be important to the intended application. Under high valve/VSI dynamic contact velocity and higher service temperature cases, applying diffusion zone alone can be beneficial to reduction of the potential abrasive wear caused by broken hard compound zone materials.
In this study, Rockwell and superficial hardness measurements, microhardness distribution, dimensional stability, and microstructural investigation were performed to reveal the correlation between microstructure and surface mechanical properties. Plint wear test was utilized to compare the wear resistance of nitrided J120V and J160. Both OLM and SEM/EDS methods have been used to characterize the primary wear mechanisms occurred in the Plint tested samples for predicting the wear performance of engine service operation.