| 摘要 |
PURPOSE:To produce a valve seat having excellent wear resistance and pitting resistance by casting molten alloy in a casting mold as pipe state, solidifying unidirectionally toward shaft direction, cutting as annular state and machining into a valve seat. CONSTITUTION:The molten alloy melted for a valve seat is supplied into the casting mold 3 in a casting apparatus 1 through a sprue 9 to be a pipe shape. Next, the poured molten metal is heated into a mold heating furnace 6 and cooled with a water cooled copper plate 4, and by suitably adjusting the ratio (G/R) of temp. gradient (G) to solidified speed (R) at interface of solid and liquid, the molten metal is solidified unidirectionally toward shaft direction of the pipe. The pipe-state casting having unidirectionally solidified structure is cut as the annular state to machine into the valve seat. By this method, the valve seat providing excellent wear resistance and pitting resistance and having high thermal conductivity, is produced under good productivity.
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