Heat Treatment Design for Martensitic Alloys for Engine Valvetrain Component Application

Martensitic type of wear and corrosion resistance alloys have been widely used for engine valve seat insert (VSI) applications. This type of martensitic alloys, in general, possess a significant lower manufacturing cost compared to nickel-based or cobalt-based VSI alloys.

Martensitic VSI alloys are used under hardened plus tempered conditions. From elevated wear resistance consideration, a higher hardness obtained through employing lower tempering treatment is preferred. On the other hand, the strength and hardness of martensitic matrix can be noticeably varied if the service temperature is greater than tempering temperature applied. Thus, heat treatment design for these alloys is one of the critical factors affecting VSI dimensional stability and retention capability during an engine operation.

A study of temper response with J120V VSI alloy has been carried along with a VSI sample dimensional stability evaluation. The temper response assessment of martensitic VSI alloy can effectively assist a sound VSI alloy heat treatment design to ensure a desired engine valvtrain performance.