In short, valve seats are seats for intake and exhaust valves. Since they are in contact with the valve, the airtightness of the combustion chamber is maintained.

Valve Seats are needed these main functions. (1)Compression gas sealing Prevents compressed gaseous bodies and combustion gas from leaking into the manifold. (2)Heat transfer Releases heat in the valve to the cylinder head. (3)Strength Holds tight when the valve is mounted. (4)Wear-resistance Hard to wear down under high heat and high load.

In addition, the following are required characteristics of valve seats: - Less aggressiveness toward the partner valve - Reasonable costs→reduction of work processes by the sinter method - Easy to machine for a customer when processing With the sintering method (see chart at right), multiple functions are incorporated in one product.