US4588441A — Process for the preparation of sintered alloys fo…

Claim 1

Independent Claim 166 words

A process for the preparation of an iron-base sintered alloy, well suited for use in valve mechanism members of parts of internal combustion engines, which has a porosity of from 5 to 15% and throughout the iron matrix of which is dispersed from 5 to 25% of an Fe-Mo intermetallic compound in the form of a phase harder than the said matrix, which comprises admixing iron powder with an effective amount of each of phoshorus-containing alloy powder, carbon powder, Fe-Mo alloy powder, and at least one powder selected from the group consisting of copper powder, bronze (copper and tin alloy) powder and a combination of copper powder and tin powder; forming the resulting composition into a green compact having a density ratio of 70-90%, pre-sintering the green compact at a temperature of from 300°-900° C., repressing the pre-sintered green compact until a density ratio of from 90-95% is reached, and finally sintering the repressed bodies at a temperature of from 1030°-1130° C. in a reducing atmosphere.

Claim 2

Dependent Claim 166 words

A process for the preparation of an iron-base sintered alloy, well suited for use in valve mechanism members of parts of internal combustion engines, which has a porosity of from 5 to 15% and throughout the iron matrix of which is dispersed from 5 to 25% of an Fe-Mo intermetallic compound in the form of a phase harder than the said matrix, which comprises admixing iron powder with an effective amount of each of phoshorus-containing alloy powder, carbon powder, Fe-Mo alloy powder, and at least one powder selected from the group consisting of copper powder, bronze (copper and tin alloy) powder and a combination of copper powder and tin powder; forming the resulting composition into a green compact having a density ratio of 70-90%, pre-sintering the green compact at a temperature of from 300°-900° C., repressing the pre-sintered green compact until a density ratio of from 90-95% is reached, and finally sintering the repressed bodies at a temperature of from 1030°-1130° C. in a reducing atmosphere.

Claim 3

Dependent Claim 14 words

A process according to claim 1 wherein the iron powder is atomized iron powder.

Claim 4

Dependent Claim 14 words

A process according to claim 1 wherein the iron powder is reduced iron powder.

Claim 5

Dependent Claim 157 words

A process for preparing an iron-base sintered alloy, well suited for use in a valve mechanism member or a part of an internal combustion engine, which has a porosity of from 5 to 15 persent and throughout the iron matrix of which is dispersed from 5 to 25% of an Fe-Mo intermetallic compound in the form of a phase harder than said matrix, which comprises: incorporating into finely-divided iron powder (having a particle size of not more than 30 microns) an effective amount of phosphorus-containing alloy powder, carbon powder, Fe-Mo alloy powder and a copper-containing powder, granulating the iron powder alone or in combination with other of said powders to an apparent particle size of from 30 to 200 microns, forming the obtained powder mixture into a green compact having a density ratio of from 70 to 90 percent, and sintering the green compact in a reducing atmosphere at a temperature of from 1030° to 1130° C.

Claim 6

Dependent Claim 157 words

A process for preparing an iron-base sintered alloy, well suited for use in a valve mechanism member or a part of an internal combustion engine, which has a porosity of from 5 to 15 persent and throughout the iron matrix of which is dispersed from 5 to 25% of an Fe-Mo intermetallic compound in the form of a phase harder than said matrix, which comprises: incorporating into finely-divided iron powder (having a particle size of not more than 30 microns) an effective amount of phosphorus-containing alloy powder, carbon powder, Fe-Mo alloy powder and a copper-containing powder, granulating the iron powder alone or in combination with other of said powders to an apparent particle size of from 30 to 200 microns, forming the obtained powder mixture into a green compact having a density ratio of from 70 to 90 percent, and sintering the green compact in a reducing atmosphere at a temperature of from 1030° to 1130° C.

Claim 7

Dependent Claim 20 words

A process according to claim 4 wherein the green compact has a density ratio of from 75 to 85 percent.

Claim 8

Dependent Claim 13 words

A process according to claim 5 wherein the copper-containing powder is copper powder.

Claim 9

Dependent Claim 13 words

A process according to claim 5 wherein the copper-containing powder comprises bronze powder.

Claim 10

Dependent Claim 19 words

A process according to claim 5 wherein the copper-containing powder comprises a mixture of copper powder and tin powder.

Claim 11

Dependent Claim 21 words

A process according to claim 5 wherein said green compact comprises from 5 to 20 percent of copper or copper alloy.

Claim 12

Dependent Claim 34 words

A process according to claim 5 wherein the phosphorus-containing alloy powder is Fe-P alloy powder or Cu-P alloy powder and comprises from 0.2 to 1.5 percent (calculated as elemental phosphorus) of said green compact.

Claim 13

Dependent Claim 20 words

A process according to claim 5 wherein the carbon powder comprises from 1 to 3 percent of said green compact.

Claim 14

Dependent Claim 23 words

A process according to claim 5 wherein molybdenum of the Fe-Mo alloy powder comprises from 3 to 15 percent of said green compact.

Claim 15

Dependent Claim 146 words

A process for preparing an iron-base sintered alloy, well suited for use in valve mechanism members or parts of internal combustion engines, which has a porosity of from 5 to 15% and throughout the iron matrix of which is dispersed from 5 to 25% of an Fe-Mo intermetallic compound in the form of a phase harder than the said matrix, which comprises: admixing an effective amount of each of phosphorus-containing alloy powder, carbon powder, Fe-Mo alloy powder and a copper-containing powder with finely-divided atomized or reduced iron powder having a particle size of not more than 30 microns and comprising in excess of 50 percent of the resulting admixture, forming the obtained powder mixture into a green compact having a density ratio of from 70 to 90 percent, and sintering the green compact in a reducing atmosphere at a temperature of from 1030° to 1130° C.

Claim 16

Dependent Claim 146 words

A process for preparing an iron-base sintered alloy, well suited for use in valve mechanism members or parts of internal combustion engines, which has a porosity of from 5 to 15% and throughout the iron matrix of which is dispersed from 5 to 25% of an Fe-Mo intermetallic compound in the form of a phase harder than the said matrix, which comprises: admixing an effective amount of each of phosphorus-containing alloy powder, carbon powder, Fe-Mo alloy powder and a copper-containing powder with finely-divided atomized or reduced iron powder having a particle size of not more than 30 microns and comprising in excess of 50 percent of the resulting admixture, forming the obtained powder mixture into a green compact having a density ratio of from 70 to 90 percent, and sintering the green compact in a reducing atmosphere at a temperature of from 1030° to 1130° C.

Claim 17

Dependent Claim 65 words

An iron-base green compact having a density ratio of from 70 to 90 percent and comprising: from 5 to 20 percent of copper or copper alloy powder, from 0.2 to 1.5 percent (calculated as elemental phosphorus) of Fe-P alloy powder or Cu-P alloy powder, from 1 to 3 percent of carbon powder, and from 3 to 15 percent (calculated as elemental molybdenum) of Fe-Mo powder.

Claim 18

Dependent Claim 65 words

An iron-base green compact having a density ratio of from 70 to 90 percent and comprising: from 5 to 20 percent of copper or copper alloy powder, from 0.2 to 1.5 percent (calculated as elemental phosphorus) of Fe-P alloy powder or Cu-P alloy powder, from 1 to 3 percent of carbon powder, and from 3 to 15 percent (calculated as elemental molybdenum) of Fe-Mo powder.

Claim 19

Dependent Claim 21 words

A green compact according to claim 14 comprising finely-divided iron powder having a particle size of not more than 30 microns.

Claim 20

Dependent Claim 28 words

A green compact according to claim 15 wherein the iron powder is in the form of granules having an apparent particle size of from 30 to 200 microns.

Claim 21

Dependent Claim 50 words

A sintered compact having a porosity ranging from 5 to 15 percent and an iron-base alloy matrix or substrate throughout which is dispersed a hard-phase Fe-Mo intermetallic compound in an area ratio of from 5 to 25 percent, the compact being that of a green compact according to claim 14.

Claim 22

Dependent Claim 20 words

A sintered compact according to claim 17 wherein the green compact has a density of from 75 to 85 percent.

Claim 23

Dependent Claim 27 words

A green compact according to claim 14 wherein the iron comprises in excess of 50 percent and is derived from atomized iron powder or reduced iron powder.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-05-12	1989-11-11	1990-05-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-05-12	1993-11-11	1994-05-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-05-12	1997-11-11	1998-05-13	$7700.00	Window Closed / Lapsed

Process for the preparation of sintered alloys for valve mechanism parts for internal combustion engines

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