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The demands on valve seat insert materials, in terms of providing greater wear-resistance at higher temperatures, enhanced machinability and using non-environmentally hazardous materials at a reasonably low cost have intensified in recent years. Due therefore to these strong demands in the market, research was made into the possibility of producing a new valve seat insert material. As a result a high speed steel based new improved material was developed, which satisfies the necessary required demands and the evaluation trials, using actual gasoline engine endurance tests, were found to be very successful.

A new high-performance and lightweight TiA1 intermetallic compound exhaust valve has been developed. The TiA1 valve can improve power output and fuel economy by contributing higher engine speeds and a reduction in valvetrain friction. It was achieved by developing a Ti-33.5A1-0.5Si-1Nb-0.5Cr (mass%) intermetallic compound, a precision casting method for TiA1 that provides a low-cost, high-quality process, and a plasma carburizing technique for assuring good wear resistance on the valve stem end, stem and face.

Sintered materials have been applied widely for Valve Seat Inserts (VSI) due to their high flexibility of material design. Hard particle dispersion type materials, which have specific microstructures in sintered material, are popular for VSIs. The load - temperature, combustion pressure, etc. - on the VSI has become severer along with increasing demands for better engine performance. (1) Especially, there is increasing tendency of the amount of wear on VSIs when used in heavy-duty engines such as diesel/gas (LPG, CNG) engines because of their dry environments.(2) In this paper, two new developed high performance VSI materials for heavy-duty engines are introduced. These materials adopt new hard particles and a new method of distribution of the solid lubricant to increase wear resistance. Hard Particles: The new developed hard particle has superior wear resistance due to increasing the amount of intermetallic compounds.