Patent ID: 6951579

Claim:
A sintered alloy for valve seats comprising a skeleton having a matrix of a tempered martensite structure, containing distributed carbides and having the following elements: carbon: 1.0 to 2.0 percent by weight chromium: 3.5 to 4.7 percent by weight molybdenum: 4.5 to 6.5 percent by weight tungsten: 5.2 to 7.0 percent by weight vanadium: 1.5 to 3.2 percent by weight iron and unavoidable impurities: remainder; wherein enstatite particles, hard alloy particles (A) with a Vickers hardness of 500 to 900, and hard alloy particles (B) with a Vickers hardness of 1000 or more are dispersed in the following proportions in the matrix of said skeleton: enstatite particles: 1 to 3 percent by weight hard alloy particles (A): 15 to 25 percent by weight hard alloy particles (B): 5 to 15 percent by weight (A + B: 35 percent by weight or less); and copper or copper alloy at 15 to 20 percent by weight is infiltrated into pores of said skeleton.