| 摘要 |
The present invention concerns a method of manufacture of valve seats which comprises forming a series of vertically stacked molds each having at least one mold cavity with a configuration approximating that of a ring-shaped valve seat insert blank. After the molds are formed, they are stacked and the cavities are connected by a common molten metal passageway in such a way that the passageway connects with an axially facing outer surface of each mold cavity to provide a lap gating relationship. Molten metal is then poured into the lap gated passageway to form a series of valve seat insert blanks each having a gate formed on an axially outer face. The blanks are then removed from the molds. Various grinding operations are then applied to the blanks and the axially outer-facing surfaces of the blanks are ground to remove the gates to form valve seats for use in internal combustion engines.
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