US4420336A
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Process of improving corrosion resistance in porous stainless steel bodies and article
Assignee: SCM Metal Products Inc
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Filing: 1982-02-11
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Granted: 1983-12-13
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Expires: 2002-02-11
Abstract
Abstract A foraminous body formed of a tin-containing atomized, compacted and sintered austenitic stainless steel powder, and process including the steps of sintering and cooling in a dissociated ammonia atmosphere.
Inventors
- 👤 Erhard Klar
- 👤 Mary A. Pao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:19
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/24; B01; B01D; B01D39/00; B01D39/14; B01D39/20; B01D39/2027; B01D39/2031; B01D39/2034; C; C22; C22C; C22C33/00; C22C33/02; C22C33/0257; C22C33/0278; C22C33/0285; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12014; Y10T428/12153
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
58 words
A foraminous body having improved corrosion resistance to aqueous nitric acid, 10%, and being formed of tin-containing water atomized, compacted and sintered austenitic stainless steel alloy powder compacted and sintered to less than 80% of theoretical density and characterized by being formed of a prealloyed stainless steel alloy powder containing from 0.1% to 10% by weight of tin.
Claim 2
Dependent Claim
58 words
A foraminous body having improved corrosion resistance to aqueous nitric acid, 10%, and being formed of tin-containing water atomized, compacted and sintered austenitic stainless steel alloy powder compacted and sintered to less than 80% of theoretical density and characterized by being formed of a prealloyed stainless steel alloy powder containing from 0.1% to 10% by weight of tin.
Claim 3
Dependent Claim
16 words
A foraminous body as defined in claim 1 wherein the stainless steel powder also contains copper.
Claim 4
Dependent Claim
20 words
A foraminous body as defined in claim 2 wherein the stainless steel powder contains about 1% tin and 2% copper.
Claim 5
Dependent Claim
92 words
A process for improving the corrosion resistance to aqueous nitric acid, 10%, of austenitic stainless steel foraminous body comprising: (a) compacting water atomized austenitic stainless steel alloy powder in the form of said foraminous body and containing from 0.1% to 10% by weight of prealloyed tin to form a compact; (b) sintering the compact in a dissociated ammonia or synthetic nitrogen atmosphere at a temperature of at least about 1125° C. to a final density less than 80% of theoretical density; and (c) cooling the sintered compact in a dissociated ammonia atmosphere.
Claim 6
Dependent Claim
92 words
A process for improving the corrosion resistance to aqueous nitric acid, 10%, of austenitic stainless steel foraminous body comprising: (a) compacting water atomized austenitic stainless steel alloy powder in the form of said foraminous body and containing from 0.1% to 10% by weight of prealloyed tin to form a compact; (b) sintering the compact in a dissociated ammonia or synthetic nitrogen atmosphere at a temperature of at least about 1125° C. to a final density less than 80% of theoretical density; and (c) cooling the sintered compact in a dissociated ammonia atmosphere.
Claim 7
Dependent Claim
22 words
A process as defined in claim 4 additionally characterized by the step of pickling the foraminous body in dilute aqueous nitric acid.
Claim 8
Dependent Claim
88 words
A process for improving the corrosion resistance to aqueous nitric acid, 10%, of an austenitic stainless steel foraminous body comprising: (a) compacting water atomized austenitic stainless steel alloy powder in the form of said foraminous body and containing from 0.1% to 10% by weight of prealloyed tin to form a compact; (b) sintering the compact in a dissociated ammonia or synthetic nitrogen atmosphere at a temperature of at least about 1125° C. to a final density less than 80% of theoretical density; and (c) cooling the sintered compact.
Claim 9
Dependent Claim
88 words
A process for improving the corrosion resistance to aqueous nitric acid, 10%, of an austenitic stainless steel foraminous body comprising: (a) compacting water atomized austenitic stainless steel alloy powder in the form of said foraminous body and containing from 0.1% to 10% by weight of prealloyed tin to form a compact; (b) sintering the compact in a dissociated ammonia or synthetic nitrogen atmosphere at a temperature of at least about 1125° C. to a final density less than 80% of theoretical density; and (c) cooling the sintered compact.
References Cited (Backward Citations)
US3425813A
Cited
US3711341A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-12 | 1987-06-13 | 1987-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-12 | 1991-06-13 | 1991-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-12 | 1995-06-13 | 1995-12-13 | $7700.00 | Window Closed / Lapsed |