Wear-resistant sintered ferrous alloy and method of producing same

DETAILED DESCRIPTION What is claimed is: 1.
A wear-resistant sintered ferrous alloy consisting essentially of 2.
0 to 8.
0% of Cr, 0.
1 to 1.
0% of B, 1.
0 to 2.
5% of Si, 0.
3 to 1.
2% of Mn, 1.
2 to 3.
8% of C, by weight, and the balance of Fe.
2.
A method of producing a wear-resistant sintered ferrous alloy, the method comprising the steps of: preparing a powder mixture which consists essentially of 2.
0 to 8.
0% of Cr, 0.
1 to 1.
0% of B, 1.
0 to 2.
5% of Si, 0.
3 to 1.
2% of Mn, 1.
2 to 3.
8% of C, by weight, and the balance of Fe; compacting said powder mixture into a body of a desired shape; and sintering said body in a nonoxidizing atmosphere.
3.
A method according to claim 2, wherein said powder mixture is prepared by mixing a powder of a cast iron with a powder of a quaternary alloy which consists essentially of 10.
0 to 35.
0% of Cr, 1.
0 to 2.
5% of B, 0.
5 to 3.
0% of Si, by weight, and the balance of Fe, the proportion of the cast iron powder to the quaternary alloy powder being in the range from 75:25 to 90:10 by weight.
4.
A method according to claim 3, wherein said cast iron contains 1.
8 to 2.
2% of Si, 0.
6 to 1.
0% of Mn, 3.
0 to 3.
5% of C by weight.
5.
A method according to claim 3, wherein the sintering is performed at a temperature in the range from about 1100.
degree.
C.
to about 1150.
degree.
C.




Description:
BACKGROUND OF THE INVENTION This invention relates to a wear-resistant sintered ferrous alloy for parts subjected to friction and a method of producing the same.
A typical example of metal parts that make continuous rubbing contact with another metal part is the rocker arm of an internal combustion engine.
It is usual to form the tip part of the rocker arm by chilled casting separately from the main part of the rocker arm or alternatively to harden the tip portion of the rocker arm made of steel by either a suitable heat treatment such as carbrizing or nitriding or a surface treatment such as chormium plating.
As the performance requirements to the recent internal combustion engines for automotive uses have become more and more severer, there is the tendency to press the rocker arms against the cams under increased pressures