Abstract: A cobalt-rich wear resistant and corrosion resistant alloy useful for parts of a combustion engine such as valve seat inserts includes, in weight % about 0.1 to about 0.8% C, about 0.1 to about 1.5% Mn, about 3 to about 5% Si, about 10 to about 20% Cr, about 5 to about 32% Fe, about 0.5 to about 4% W, about 10 to about 30% Mo, up to about 20% Ni, about 20 to about 40% Co, up to about 6% V, up to about 3% Nb, total V plus Nb of about 0.5 to about 8.5% and balance unavoidable impurities including up to 0.035% P, up to 0.015% S and up to 0.250% N.

Abstract: A cobalt-rich wear resistant and corrosion resistant alloy useful for parts of a combustion engine such as valve seat inserts includes, in weight % about 0.1 to about 0.8% C, about 0.1 to about 1.5% Mn, about 3 to about 5% Si, about 10 to about 20% Cr, about 5 to about 32% Fe, about 0.5 to about 4% W, about 10 to about 30% Mo, up to about 20% Ni, about 20 to about 40% Co, up to about 6% V, up to about 3% Nb, total V plus Nb of about 0.5 to about 8.5% and balance unavoidable impurities including up to 0.035% P, up to 0.015% S and up to 0.250% N.

Abstract: Disclosed herein is a nickel based alloy comprising, in weight percentage: carbon from about 0.5 to about 1.5; chromium from about 25 to about 35; tungsten from about 12 to about 18; iron from about 3.5 to about 8.5; molybdenum from about 1 to about 8; manganese up to about 0.50; silicon up to about 1.0; and the balance nickel and incidental impurities. The alloy is suitable for valve seat insert applications in internal combustion engines.

Abstract: A cobalt-rich wear resistant and corrosion resistant alloy comprises in weight %, 0.5 to 1.2% C, 0.6 to 2.1% Si, 17 to 24% Cr, 27 to 38.5% Fe, 1.4 to 20% W, 3.8 to 9.7% Mo, less than 1% Ni and balance Co. A preferred cobalt-rich alloy comprises in weight %, 0.5 to 0.9 C, 0.75 to 1.15% Si, 17.5 to 20.5 Cr, 27.0 to 32.0 Fe, 12.5 to 16.5 W, 6.25 to 8.25 Mo, 0.45 to 1.00 Ni and balance Co. The alloy preferably has a microstructure free of primary carbides and comprises up to about 50% by volume eutectic reaction phases in a solid solution matrix. The solid solution matrix is an ?Fe-?Co face-centered cubic solution with W, Cr and Mo as solute elements and the eutectic reaction products comprise a (Co,Cr)7(W,Mo)6 phase and an ?Fe-?Co phase. The alloy is useful as a valve seat insert for internal combustion engines such as diesel engines.

Abstract: A cobalt-rich wear resistant and corrosion resistant alloy comprises in weight %, 0.5 to 1.2% C, 0.6 to 2.1% Si, 17 to 24% Cr, 27 to 38.5% Fe, 1.4 to 20% W, 3.8 to 9.7% Mo, less than 1% Ni and balance Co. A preferred cobalt-rich alloy comprises in weight %, 0.5 to 0.9 C, 0.75 to 1.15% Si, 17.5 to 20.5 Cr, 27.0 to 32.0 Fe, 12.5 to 16.5 W, 6.25 to 8.25 Mo, 0.45 to 1.00 Ni and balance Co. The alloy preferably has a microstructure free of primary carbides and comprises up to about 50% by volume eutectic reaction phases in a solid solution matrix. The solid solution matrix is an ?Fe-?Co face-centered cubic solution with W, Cr and Mo as solute elements and the eutectic reaction products comprise a (Co, Cr)7(W,Mo)6 phase and an ?Fe-?Co phase. The alloy is useful as a valve seat insert for internal combustion engines such as diesel engines.

Abstract: A prehardened valve seat insert and a process for forming a prehardened valve seat insert for insertion into a cylinder head or an engine block of an internal combustion engine. The process comprises the steps of (a) forming the valve seat insert; (b) precision machining the valve seat insert to precise tolerances so that the valve seat insert can be installed in one of the cylinder head and the engine block without the need for additional seat machining; and (c) treating the valve seat insert to form a wear resistant surface layer prior to inserting the valve seat insert into one of the cylinder head and the engine block.

Abstract: A prehardened valve seat insert and a process for forming a prehardened valve seat insert for insertion into a cylinder head or an engine block of an internal combustion engine. The process comprises the steps of (a) forming the valve seat insert; (b) precision machining the valve seat insert to precise tolerances so that the valve seat insert can be installed in one of the cylinder head and the engine block without the need for additional seat machining; and (c) treating the valve seat insert to form a wear resistant surface layer prior to inserting the valve seat insert into one of the cylinder head and the engine block.

Abstract: A method of manufacturing surface treated, prefinished valve seat inserts. The method entails forming the valve seat insert, precision machining the valve seat insert to precise tolerances so that the valve seat insert can be installed in one of the cylinder head and engine block without the need for additional seat machining and treating the valve seat insert with a wear resistant treatment prior to inserting the valve seat insert into on of the cylinder head and engine block.