Patent US2405111A successfully refreshed from Google Patents.
US4028100A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat treating atmospheres
Assignee: ICM Krebsoge Inc
•
Filing: 1974-10-15
•
Granted: 1977-06-07
•
Expires: 1994-10-15
Abstract
Abstract A heat treating atmosphere and method for its use wherein the atmosphere provides precise control over carbon content in metal parts, such as steel, and which is particularly applicable to powder metal sintering. The method uses a mixture of resultant constituents from dissociated ammonia and methane combusted with air to provide an atmosphere of controlled carbon potential. The ammonia is dissociated, the methane is combusted with air and the resultant constituents are mixed together prior to introduction into the heat treating furnace. The method prevents the formation of undesirable hard and brittle phases of carbides during sintering, the resulting products being free of segregated high carbon constituents, i.e., cementite, and being easier to machine, thus providing much longer cutting tool life.
Inventors
- 👤 Henry F. Latva
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:28
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/10; B22F3/1003; B22F3/1007; C; C21; C21D; C21D1/00; C21D1/74; C21D1/76
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
54 words
A method of sintering steel powder metal compacts, comprising: combusting methane to form CO, N 2 and H 2 constituents, dissociating ammonia to form N 2 and H 2 constituents, blending the constituents together and subsequently introducing the blended constituents into a sintering environment containing the compact while heating the compact at sintering temperatures.
Claim 2
Independent Claim
54 words
A method of sintering steel powder metal compacts, comprising: combusting methane to form CO, N 2 and H 2 constituents, dissociating ammonia to form N 2 and H 2 constituents, blending the constituents together and subsequently introducing the blended constituents into a sintering environment containing the compact while heating the compact at sintering temperatures.
Claim 3
Dependent Claim
42 words
The method of claim 1 wherein the sintering is maintained for a period of time sufficient to establish an equilibrium condition between the mixed constituents of the methane and ammonia and the carbon content of the compact whereby carbon content is controlled.
Claim 4
Dependent Claim
52 words
The method of claim 1 wherein the desired carbon content is about 0.20% to 0.25%, the ammonia and methane are provided in a ratio by volume of about 60/40, and following dissociation and combustion of the gases, respectively, the resulting constituents are mixed together to provide the sintering atmosphere for the compact.
Claim 5
Dependent Claim
11 words
The method of claim 2 wherein the compact additionally include manganese.
Claim 6
Dependent Claim
51 words
The method of claim 1 wherein the desired carbon content is about 0.35% carbon, the ammonia and methane are provided in a ratio by volume of about 50/50 and following dissociation and combustion of the gases respectively, the resulting constituents are mixed together to provide the sintering atmosphere for the compact.
Claim 7
Dependent Claim
11 words
The method of claim 5 wherein the compact additionally includes manganese.
Claim 8
Dependent Claim
49 words
The method of claim 1 wherein the desired carbon content is about 0.60%, the ammonia and methane are provided in a ratio of about 40/60 and the following dissociation and combustion of the gases respectively, the resulting constituents are mixed together to provide the sintering atmosphere for the compact.
Claim 9
Dependent Claim
51 words
The method of claim 1 wherein the desired carbon content of the compact is about 0.85% and the overall ratio of ammonia to methane is about 20/80 and the following dissociation and combustion of the gases respectively, the resulting constituents are mixed together to provide the sintering atmosphere for the compact.
Claim 10
Independent Claim
94 words
A method of sintering comprising: providing an endothermic generator and an ammonia dissociator, passing a flow of methane into the generator and a flow of ammonia into the dissociator, regulating the flow of the two gases relative to each other, combusting the methane in the generator and dissociating the ammonia in the dissociator, providing a steel powder metal compact in a sintering environment, passing the combusted constituents out of the generator, passing the dissociated constituents out of the dissociator, mixing constituents together, and introducing the mixed constituents into the sintering environment of the compact.
Claim 11
Independent Claim
94 words
A method of sintering comprising: providing an endothermic generator and an ammonia dissociator, passing a flow of methane into the generator and a flow of ammonia into the dissociator, regulating the flow of the two gases relative to each other, combusting the methane in the generator and dissociating the ammonia in the dissociator, providing a steel powder metal compact in a sintering environment, passing the combusted constituents out of the generator, passing the dissociated constituents out of the dissociator, mixing constituents together, and introducing the mixed constituents into the sintering environment of the compact.
Claim 12
Dependent Claim
12 words
The method of claim 9 wherein the compact is a steel alloy.
Claim 13
Dependent Claim
38 words
The method of claim 4 wherein: the flow of the two gases relative to each other is regulated to provide a volume ratio of about 60/40, and the steel compact includes about 0.18% to 0.25% by weight carbon.
Claim 14
Dependent Claim
11 words
The method of claim 11 wherein the compact additionally includes manganese.
Claim 15
Dependent Claim
36 words
The method of claim 9 wherein: the flow of the two gases relative to each other is regulated to provide a volume ratio of about 50/50, and the steel compact includes about 0.35% by weight carbon.
Claim 16
Dependent Claim
11 words
The method of claim 13 wherein the compact additionally includes manganese.
Claim 17
Dependent Claim
36 words
The method of claim 9 wherein the flow of the two gases relative to each other is regulated to provide a volume ratio of about 40/60, and the steel compact includes about 0.60% by weight carbon.
Claim 18
Dependent Claim
11 words
The method of claim 15 wherein the compact additionally includes manganese.
Claim 19
Dependent Claim
36 words
The method of claim 9 wherein: the flow of the two gases relative to each other is regulated to provide a volume ratio of about 20/80, and the steel compact includes about 0.85% by weight carbon.
Claim 20
Dependent Claim
11 words
The method of claim 17 wherein the compact additionally includes manganese.
Claim 21
Independent Claim
75 words
A method of sintering a steel powder metal compact, comprising: combusting a hydrocarbon fuel gas to form CO, N 2 and H 2 constituents, dissociating ammonia to form N 2 and H 2 constituents, mixing the constituents of the methane and ammonia together in controlled amounts depending upon the desired carbon content of the compact, and subsequently introducing the mixed constituents into a sintering environment containing the compact while heating the compact at sintering temperatures.
Claim 22
Independent Claim
75 words
A method of sintering a steel powder metal compact, comprising: combusting a hydrocarbon fuel gas to form CO, N 2 and H 2 constituents, dissociating ammonia to form N 2 and H 2 constituents, mixing the constituents of the methane and ammonia together in controlled amounts depending upon the desired carbon content of the compact, and subsequently introducing the mixed constituents into a sintering environment containing the compact while heating the compact at sintering temperatures.
Claim 23
Independent Claim
108 words
A method of sintering comprising: providing an endothermic generator and an ammonia dissociator, passing a flow of hydrocarbon fuel gas into the generator and a flow of ammonia into the dissociator, regulating the flow of the two gases relative to each other, combusting the hydrocarbon fuel gas in the generator and dissociating the ammonia in the dissociator, providing a powder metal compact in a sintering environment, mixing constituents resulting from the combustion of the hydrocarbon fuel gas with constituents resulting from the dissociation of the ammonia, the mixing being in predetermined relative amounts of the constituents, and introducing the mixed constituents into the sintering environment of the compact.
Claim 24
Independent Claim
108 words
A method of sintering comprising: providing an endothermic generator and an ammonia dissociator, passing a flow of hydrocarbon fuel gas into the generator and a flow of ammonia into the dissociator, regulating the flow of the two gases relative to each other, combusting the hydrocarbon fuel gas in the generator and dissociating the ammonia in the dissociator, providing a powder metal compact in a sintering environment, mixing constituents resulting from the combustion of the hydrocarbon fuel gas with constituents resulting from the dissociation of the ammonia, the mixing being in predetermined relative amounts of the constituents, and introducing the mixed constituents into the sintering environment of the compact.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-06 | 1980-12-06 | 1981-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-06 | 1984-12-06 | 1985-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-06 | 1988-12-06 | 1989-06-07 | $7700.00 | Window Closed / Lapsed |