Sintered alloy for valve seats, valve seat and manufacturing method thereof
AssigneeTeikoku Piston Ring Co., Ltd.
InventorYoshio Koyama
Life of this patent
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Abstract
A sintered alloy for valve seats is comprised of carbon at 1 to 2 percent by weight, chromium at 3.5 to 4.7 percent by weight, molybdenum at 4.5 to 6.5 percent by weight, tungsten at 5.2 to 7.0 percent by weight, vanadium at 1.5 to 3.2 percent by weight, and the remainder of iron and unavoidable impurities. Enstatite particles at 1 to 3 percent by weight, hard alloy particles (A) with a Vickers hardness of 500 to 900 at 15 to 25 percent by weight, and hard alloy particles (B) with a Vickers hardness of 1000 or more at 5 to 15 percent by weight (A+B=35 percent by weight or less) are dispersed in the matrix of the sintered alloy skeleton distributed with carbide. Copper or copper alloy at 15 to 20 percent by weight is infiltrated into pores of the skeleton.
Claims8
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.
Dependencies are inferred from the claim text.