US4190440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for fabricating steel from ferrous metal particles
Assignee: Primerica Inc
•
Filing: 1978-10-19
•
Granted: 1980-02-26
•
Expires: 1998-10-19
Abstract
Abstract A process for conditioning ferrous particles with heat and a reducing atmosphere to reduce the oxygen content of the particles in a non-agglomerative manner and to make the conditioned particles readily pourable and free-flowing, and to process the particles into steel strip.
Inventors
- 👤 Albert J. Klein
- 👤 Chiou-Tse Chen
- 👤 Lou Kohl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:19
CPC Classifications
C; C22; C22C; C22C33/00; C22C33/02; C22C33/0235; B; B22; B22F; B22F1/00; B22F1/14; B22F1/145; B22F3/00; B22F3/10; B22F3/1003; B22F3/1007; B22F3/18
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
254 words
A process for producing steel strip comprising: (a) providing as-water-atomized ferrous metal powder whose particles have a martensitic structure, a surface layer of mostly iron oxide thereon, a particle size distribution range which includes no more than traces of about 20 mesh, no more than about 16 weight percent smaller than 230 mesh and the balance between 20 and 230 mesh and a total oxygen content of up to about 1.5 weight percent; (b) heating said particles at a temperature between about 900° and 1200° F. for a conditioning period of at least about 10 but no longer than about 30 minutes while simultaneously agitating said particles and continuously flooding them with a controlled reducing atmosphere in sufficient volume to maintain the reducing action throughout said conditioning period to dry the powder particles and to substantially reduce the oxygen content of reducible iron oxides in the surface layer and to reduce the total oxygen content of the powder particles to less than about 0.30 weight percent, thereby obtaining free-flowing, substantially non-agglomerated, un-annealed conditioned, ferrous powder particles having a tempered martensitic structure and a porous, substantially pure ferrite layer thereon; (c) compacting said heated particles in a controlled reducing or neutral atmosphere to produce a hot compacted strip; (d) further heating said compacted strip in a controlled reducing or neutral atmosphere to between 1800°-2400° F.; (e) hot-rolling said heated compacted strip in a controlled neutral or reducing atmosphere; and (f) cooling said hot-rolled strip to between 200°-400° F. in a controlled reducing or neutral atmosphere.
Claim 2
Dependent Claim
254 words
A process for producing steel strip comprising: (a) providing as-water-atomized ferrous metal powder whose particles have a martensitic structure, a surface layer of mostly iron oxide thereon, a particle size distribution range which includes no more than traces of about 20 mesh, no more than about 16 weight percent smaller than 230 mesh and the balance between 20 and 230 mesh and a total oxygen content of up to about 1.5 weight percent; (b) heating said particles at a temperature between about 900° and 1200° F. for a conditioning period of at least about 10 but no longer than about 30 minutes while simultaneously agitating said particles and continuously flooding them with a controlled reducing atmosphere in sufficient volume to maintain the reducing action throughout said conditioning period to dry the powder particles and to substantially reduce the oxygen content of reducible iron oxides in the surface layer and to reduce the total oxygen content of the powder particles to less than about 0.30 weight percent, thereby obtaining free-flowing, substantially non-agglomerated, un-annealed conditioned, ferrous powder particles having a tempered martensitic structure and a porous, substantially pure ferrite layer thereon; (c) compacting said heated particles in a controlled reducing or neutral atmosphere to produce a hot compacted strip; (d) further heating said compacted strip in a controlled reducing or neutral atmosphere to between 1800°-2400° F.; (e) hot-rolling said heated compacted strip in a controlled neutral or reducing atmosphere; and (f) cooling said hot-rolled strip to between 200°-400° F. in a controlled reducing or neutral atmosphere.
Claim 3
Dependent Claim
13 words
The method of claim 1 and further comprising cold rolling said cooled strip.
Claim 4
Dependent Claim
13 words
The method of claim 2 and further comprising trimming said cold rolled strip.
Claim 5
Dependent Claim
12 words
The method of claim 3 and further comprising coiling said trimmed strip.
Claim 6
Dependent Claim
15 words
The method of claim 1 in which said controlled atmosphere is a controlled reducing atmosphere.
Claim 7
Dependent Claim
67 words
The method of claim 5 in which said controlled reducing atmosphere is chosen from the group consisting of substantially pure hydrogen; substantially dissociated ammonia; a mixture of substantially forty percent nitrogen, substantially forty percent hydrogen and substantially twenty percent carbon monoxide; and a mixture of substantially ninety percent nitrogen, zero to five percent hydrogen, zero to five percent carbon monoxide and zero to ten percent hydrocarbon gases.
Claim 8
Dependent Claim
21 words
The method of claim 1 in which said controlled atmosphere is a gas which has substantially no chemical reaction with steel.
Claim 9
Dependent Claim
14 words
The method of claim 1 in which said controlled atmosphere for cooling is nitrogen.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein said reducing atmosphere is substantially pure hydrogen.
Claim 11
Dependent Claim
13 words
The method of claim 1 wherein said reducing atmosphere is substantially dissociated ammonia.
Claim 12
Dependent Claim
27 words
The method of claim 1 wherein said reducing atmosphere is a mixture of substantially forty percent nitrogen, substantially forty percent hydrogen, and substantially twenty percent carbon monoxide.
Claim 13
Dependent Claim
35 words
The method of claim 1 wherein said reducing atmosphere is a mixture of substantially ninety percent nitrogen, zero to five percent hydrogen, zero to five percent carbon monoxide and zero to ten percent hydrocarbon gases.
Claim 14
Dependent Claim
32 words
The method of claim 1 wherein the time period at temperature of said particles is at least 10 minutes and the processing temperature of said particles is between 1000° and 1200° F.
Claim 15
Dependent Claim
32 words
The method of claim 1 wherein the time period at temperature of said particles is at least 15 minutes, and the processing temperature of said particles is between 900° and 1200° F.
Claim 16
Dependent Claim
32 words
The method of claim 1 wherein the time period at temperature of said particles is at least 20 minutes and the processing temperature of said particles is between 900° and 1200° F.
Claim 17
Dependent Claim
32 words
The method of claim 1 wherein the time period at temperature of said particles is at least 30 minutes and the processing temperature of said particles is between 900° and 1200° F.
Claim 18
Dependent Claim
16 words
The method of claim 1 wherein the processing temperature of said particles is substantially 1100° F.
Claim 19
Dependent Claim
29 words
The method of claim 1 wherein the temperature of said particles is substantially 900° F., and the time period at temperature of said particles is at least 30 minutes.
Claim 20
Dependent Claim
30 words
The method of claim 1 wherein the processing temperature of said particles is substantially 900° F. and the time period at temperature of said particles is at least 15 minutes.
Claim 21
Dependent Claim
29 words
The method of claim 1 wherein the processing temperature of said particles is substantially 1000°F. and the time period at temperature of said particles is at least 15 minutes.
Claim 22
Dependent Claim
26 words
The method of claim 1 wherein the processing temperature of said particles is 1100° F., and the time period at temperature is at least 10 minutes.
Claim 23
Dependent Claim
27 words
The method of claim 1 wherein the processing temperature of said particles is substantially 1200° F., and the time period at temperature is at least 10 minutes.
Claim 24
Dependent Claim
19 words
The method of claim 1 wherein the time period at temperature of said particles is at least 20 minutes.
Claim 25
Dependent Claim
18 words
The method of claim 1 wherein the structure of most of the core of said particles is martensite.
Claim 26
Dependent Claim
11 words
The method of claim 1 wherein said particles are as-water-atomized-ferrous-metal particles.
Claim 27
Dependent Claim
71 words
The method of claim 1 wherein the size distribution of said particles are substantially as follows: ______________________________________
% By Weight Mesh
______________________________________
Trace +20 mesh
18% maximum -20 and +40 mesh
22% ± 3% -40 and +60 mesh
17% ± 2% -60 and +80 mesh
10% ± 2% -80 and +100 mesh
11% ± 2% -100 and +140 mesh
13% ± 2% -140 and +230 mesh
16% maximum -230 mesh
______________________________________
Claim 28
Dependent Claim
39 words
The method of claim 1 wherein the chemical composition of said particles are substantially as follows: ______________________________________
Element Weight Percent
______________________________________
O 1.50% maximum
C 0.006% to 0.20%
Si 0.02% maximum
Mn 0.05% to 0.30%
P 0.015% maximum
______________________________________
Claim 29
Dependent Claim
12 words
The method of claim 1 in which said hot-rolling is dry hot-rolling.
Claim 30
Dependent Claim
13 words
The method of claim 28 and further comprising cold rolling said cooled strip.
Claim 31
Dependent Claim
13 words
The method of claim 29 and further comprising trimming said cold rolled strip.
Claim 32
Dependent Claim
12 words
The method of claim 30 and further comprising coiling said trimmed strip.
Claim 33
Dependent Claim
15 words
The method of claim 28 in which said controlled atmosphere is a controlled reducing atmosphere.
Claim 34
Dependent Claim
67 words
The method of claim 32 in which said controlled reducing atmosphere are chosen from the group consisting of substantially pure hydrogen; substantially dissociated ammonia; a mixture of substantially forty percent nitrogen, substantially forty percent hydrogen and substantially twenty percent carbon monoxide; and a mixture of substantially ninety percent nitrogen, zero to five percent hydrogen, zero to five percent carbon monoxide and zero to ten percent hydrocarbon gases.
Claim 35
Dependent Claim
21 words
The method of claim 28 in which said controlled atmosphere is a gas which has substantially no chemical reaction with steel.
Claim 36
Dependent Claim
12 words
The method of claim 28 in which said controlled atmosphere is nitrogen.
Claim 37
Dependent Claim
13 words
The method of claim 28 wherein said reducing atmosphere is substantially pure hydrogen.
Claim 38
Dependent Claim
13 words
The method of claim 28 wherein said reducing atmosphere is substantially dissociated ammonia.
Claim 39
Dependent Claim
27 words
The method of claim 28 wherein said reducing atmosphere is a mixture of substantially forty percent nitrogen, substantially forty percent hydrogen, and substantially twenty percent carbon monoxide.
Claim 40
Dependent Claim
35 words
The method of claim 28 wherein said reducing atmosphere is a mixture of substantially ninety percent nitrogen, zero to five percent hydrogen, zero to five percent carbon monoxide and zero to ten percent hydrocarbon gases.
Claim 41
Dependent Claim
32 words
The method of claim 28 wherein the time period at temperature of said particles is at least 10 minutes and the processing temperature of said particles is between 1000° and 1200° F.
Claim 42
Dependent Claim
32 words
The method of claim 28 wherein the time period at temperature of said particles is at least 15 minutes, and the processing temperature of said particles is between 900° and 1200° F.
Claim 43
Dependent Claim
32 words
The method of claim 28 wherein the time period at temperature of said particles is at least 20 minutes and the processing temperature of said particles is between 900° and 1200° F.
Claim 44
Dependent Claim
32 words
The method of claim 28 wherein the time period at temperature of said particles is at least 30 minutes and the processing temperature of said particles is between 900° and 1200° F.
Claim 45
Dependent Claim
16 words
The method of claim 28 wherein the processing temperature of said particles is substantially 1100° F.
Claim 46
Dependent Claim
29 words
The method of claim 28 wherein the temperature of said particles is substantially 900° F., and the time period at temperature of said particles is at least 30 minutes.
Claim 47
Dependent Claim
30 words
The method of claim 28 wherein the processing temperature of said particles is substantially 900° F. and the time period at temperature of said particles is at least 15 minutes.
Claim 48
Dependent Claim
30 words
The method of claim 28 wherein the processing temperature of said particles is substantially 1000° F. and the time period at temperature of said particles is at least 15 minutes.
Claim 49
Dependent Claim
26 words
The method of claim 28 wherein the processing temperature of said particles is 1100° F., and the time period at temperature is at least 10 minutes.
Claim 50
Dependent Claim
27 words
The method of claim 28 wherein the processing temperature of said particles is substantially 1200° F., and the time period at temperature is at least 10 minutes.
Claim 51
Dependent Claim
19 words
The method of claim 28 wherein the time period at temperature of said particles is at least 20 minutes.
Claim 52
Dependent Claim
18 words
The method of claim 28 wherein the structure of most of the core of said particles is martensite.
Claim 53
Dependent Claim
11 words
The method of claim 28 wherein said particles are as-water-atomized-ferrous-metal particles.
Claim 54
Dependent Claim
71 words
The method of claim 28 wherein the size distribution of said particles are substantially as follows: ______________________________________
% By Weight Mesh
______________________________________
Trace +20 mesh
18% maximum -20 and +40 mesh
22% ± 3% -40 and +60 mesh
17% ± 2% -60 and +80 mesh
10% ± 2% -80 and +100 mesh
11% ± 2% -100 and +140 mesh
13% ± 2% -140 and +230 mesh
16% maximum -230 mesh
______________________________________
Claim 55
Dependent Claim
39 words
The method of claim 28 wherein the chemical composition of said particles are substantially as follows: ______________________________________
Element Weight Percent
______________________________________
O 1.50% maximum
C 0.006% to 0.20%
Si 0.02% maximum
Mn 0.05% to 0.30%
P 0.015% maximum
______________________________________
References Cited (Backward Citations)
US3334408A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-25 | 1983-08-27 | 1984-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-25 | 1987-08-27 | 1988-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-25 | 1991-08-27 | 1992-02-26 | $7700.00 | Window Closed / Lapsed |