| 摘要 |
PROBLEM TO BE SOLVED: To provide a wear resistant sintered alloy for a valve seat improved in impact resistance and wear resistance and free from the fear of the leakage of gas or the like by the prevention of incorporation of huge grains, and to provide its producing method. SOLUTION: This wear resistant sintered alloy for a valve seat is obtained by performing the first stage in which an alloy essentially consisting of iron and blended with prescribed amounts of carbon, chromium, molybdenum, vanadium, tungsten, silicon, cobalt and manganese is compacted under the facial pressure of 5 to 8 ton/cm2, the second stage in which the compact is sintered at 1,140 to 1,180 deg.C and is air-cooled, the third stage in which the sintered body is subjected to subzero cooling treatment at -200 to -160 deg.C, the fourth stage in which lead is deposited thereon and the last barrel stage at a same temperature of lead deposition. In this alloy, the size of the grains is extremely small, and its magnetic lubricity and workability are improved accompanied with the increase of wear resistance and impact resistance.
|
