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US4435483A
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Loose sintering of spherical ferritic-austenitic stainless steel powder and porous body
Assignee: Nyby Uddeholm Powder AB
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Filing: 1982-02-08
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Granted: 1984-03-06
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Expires: 2002-02-08
Abstract
Abstract A porous sintered body, preferably a filter or filter material, with good corrosion resistance and with a pore volume which can be predicted within specified comparatively narrow limits, is made by loose sintering of a preferably gas-atomized spherical powder a ferritic-austenitic stainless steel.
Inventors
- 👤 Christer Ahslund
- 👤 Karl H. T. Andersson
- 👤 Sven S. Bergh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:06
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/10; B22F3/11; 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: 12
Claim 1
Independent Claim
62 words
A porous sintered body, with good resistance to corrosion and with a pore volume which can be predetermined within given narrow limits, produced by loose sintering of a spherical powder of stainless steel at a sintering temperature between 1200° C. and 1600° C., wherein said stainless steel has a ferritic-austenitic structure at room temperature and a ferritic structure at the sintering temperature.
Claim 2
Dependent Claim
62 words
A porous sintered body, with good resistance to corrosion and with a pore volume which can be predetermined within given narrow limits, produced by loose sintering of a spherical powder of stainless steel at a sintering temperature between 1200° C. and 1600° C., wherein said stainless steel has a ferritic-austenitic structure at room temperature and a ferritic structure at the sintering temperature.
Claim 3
Dependent Claim
16 words
The sintered body as claimed in claim 1, wherein said sintered body is a filter material.
Claim 4
Dependent Claim
15 words
The sintered body as claimed in claim 1, wherein said sintered body is a filter.
Claim 5
Dependent Claim
41 words
The sintered body as claimed in claim 1, wherein the ferritic-austenitic steel has the composition C:0.1% maximum, Cr: 18-26%, Ni: 2-8%, Mo: 6% maximum, other alloying substances totalling not more than 5%, the balance being iron and impurities in normal amounts.
Claim 6
Dependent Claim
33 words
The sintered body as claimed in claim 4, wherein the steel has the composition C: 0.05% maximum, Cr: 20-25%, Ni: 3-6%, Mo: 1-5%, and the balance being iron and impurities in normal amounts.
Claim 7
Dependent Claim
19 words
The sintered body as claimed in claim 5, wherein the powder has an oxygen content not exceeding 1,000 ppm.
Claim 8
Dependent Claim
19 words
The sintered body as claimed in claim 6, wherein the powder has an oxygen content not exceeding 200 ppm.
Claim 9
Independent Claim
65 words
A method for producing a porous sintered body, with good corrosion resistance and with a given pore volume which can be predetermined within narrow limits, comprising loose sintering of a gas-atomized spherical powder of a stainless steel which has ferritic-austenitic structure at room temperature, said loose sintering being conducted in the ferritic state of the steel at a temperature between 1200° C. and 1600° C.
Claim 10
Independent Claim
65 words
A method for producing a porous sintered body, with good corrosion resistance and with a given pore volume which can be predetermined within narrow limits, comprising loose sintering of a gas-atomized spherical powder of a stainless steel which has ferritic-austenitic structure at room temperature, said loose sintering being conducted in the ferritic state of the steel at a temperature between 1200° C. and 1600° C.
Claim 11
Dependent Claim
20 words
The method according to claim 8, wherein the sintering is performed at a temperature between 1250° C. and 1400° C.
Claim 12
Dependent Claim
26 words
The method as claimed in claim 9, wherein the powder is subjected to a pressure loading during sintering of between 10 and 1000 Newton/cm 2 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |