Iron-chromium alloy with improved compressive yield strength and method of making and use thereof
AssigneeL. E. Jones Company
InventorsCong Yue Qiao, Todd Trudeau
Life of this patent
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Abstract
A chromium-iron alloy comprises in weight %, 1 to 3% C, 1 to 3% Si, up to 3% Ni, 25 to 35% Cr, 1.5 to 3% Mo, up to 2% W, 2.0 to 4.0% Nb, up to 3.0% V, up to 3.0% Ta, up to 1.2% B, up to 1% Mn and 43 to 64% Fe. In a preferred embodiment, the chromium-iron alloy comprises in weight %, 1.5 to 2.3% C, 1.6 to 2.3% Si, 0.2 to 2.2% Ni, 27 to 34% Cr, 1.7 to 2.5% Mo, 0.04 to 2% W, 2.2 to 3.6% Nb, up to 1% V, up to 3.0% Ta, up to 0.7% B, 0.1 to 0.6% Mn and 43 to 64% Fe. The chromium-iron alloy is useful for valve seat inserts for internal combustion engines such as diesel or natural gas engines.
Claims16
A chromium-iron alloy comprising in weight %:
- 1 to 3% C;
- 1 to 3% Si;
- up to 3% Ni;
- 25 to 35% Cr;
- 1.5 to 3% Mo;
- up to 2% W;
- 2.0 to 4.0% Nb;
- up to 3.0% V;
- up to 3.0% Ta;
- up to 1.2% B;
- up to 1% Mn;
- 43 to 64% Fe;
- and
- comprising a ferrite-carbide matrix with spherical and/or polyhedron-shaped particles distributed throughout the ferrite-carbide matrix.
A chromium-iron alloy comprising in weight %:
- 1 to 3% C;
- 1 to 3% Si;
- up to 3% Ni;
- 25 to 35% Cr;
- 1.5 to 3% Mo;
- up to 2% W;
- 2.0 to 4.0% Nb;
- up to 3.0% V;
- up to 3.0% Ta;
- up to 1.2% B;
- up to 1% Mn;
- 43 to 64% Fe;
- wherein the chromium-iron alloy has an as-cast bulk hardness from 40 to 56 Rockwell C;
- a hot hardness (HV10) from 450 to 500 at 75° F., from 280 to 300 at 1000° F., from 55 to 70 at 1600° F.;
- a compressive yield strength from 90 to 220 KSi at 75° F., from 70 to 130 at 1000° F.;
- a linear thermal expansion coefficient from 8×10−6 to 12×10−6/° C.
A valve seat insert made of a chromium-iron alloy comprising in weight %:
- 1 to 3% C;
- 1 to 3% Si;
- up to 3% Ni;
- 25 to 35% Cr;
- 1.5 to 3% Mo;
- up to 2% W;
- 2.0 to 4.0% Nb;
- up to 3.0% V;
- up to 3.0% Ta;
- up to 1.2% B;
- up to 1% Mn;
- 43 to 64% Fe;
- wherein the insert exhibits a dimensional stability of less than 0.3×10−3 inch per inch of insert outside diameter (O.D.) after heating for 20 hours at 1200° F.
A method of making a chromium-iron alloy comprising in weight %:
- 1 to 3% C;
- 1 to 3% Si;
- up to 3% Ni;
- 25 to 35% Cr;
- 1.5 to 3% Mo;
- up to 2% W;
- 2.0 to 4.0% Nb;
- up to 3.0% V;
- up to 3.0% Ta;
- up to 1.2% B;
- up to 1% Mn;
- 43 to 64% Fe;
- wherein:
- (a) the chromium-iron alloy is cast into a shaped component from a melt at a temperature from about 2700° F. to about 3000° F.;
- or
- (b) a powder of the chromium-iron alloy is pressed into a shaped component and sintered at a temperature from about 1950° F. to about 2300° F. in a reducing atmosphere, wherein the reducing atmosphere is hydrogen or a mixture of dissociated ammonia and nitrogen.
Dependencies are inferred from the claim text.