US3871925A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of conditioning 18{14 8 stainless steel
Assignee: Pall Filtration and Separations Group Inc
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Filing: 1972-11-29
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Granted: 1975-03-18
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Expires: 1992-11-29
Abstract
Abstract A method of conditioning type 18-8 stainless steel material for cold work by subjecting the material to a mechanical deforming operation of less than 85% above the Md30 temperature. This processing enables the stainless steel, upon cold work, to transform the austenite to martensite at a much higher rate than in unconditioned stainless steel so that much higher tensile strengths may be achieved with much lower amounts of cold work. In another embodiment of the invention, a method of producing a type 18-8 stainless steel with a tensile strength of over 325,000 psi. at about a 60% cold work level is achieved.
Inventors
- 👤 John Nunes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:53
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/06; C21D6/00; C21D6/004
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
70 words
A PROCESS FOR CONDITIONING TYPE 18-8 STAINLESS STEEL FOR SUBSEQUENTLY COLD DEFORMING COMPRISING THE STEPS OF: A. ANNEALING THE MATERIAL IN A TEMPERATURE RANGE OF FROM ABOUT 1,500*F, AND, B. MECHANICALLY DEFORMING THE MATERIAL NOT MORE THAN APPROXIMATELY 85% AT A TEMPERATURE OF FROM 150*F ABOVE THE MD30 TEMPERATURE, THEREBY C. DECREASING THE AMBIENT TEMPERATURE STABILITY OF THE AUSTENITE WHEREIN IT FORMS MARTENSITE AT RAPID RATE UPON BEING COLD WORKED.
Claim 2
Dependent Claim
70 words
A PROCESS FOR CONDITIONING TYPE 18-8 STAINLESS STEEL FOR SUBSEQUENTLY COLD DEFORMING COMPRISING THE STEPS OF: A. ANNEALING THE MATERIAL IN A TEMPERATURE RANGE OF FROM ABOUT 1,500*F, AND, B. MECHANICALLY DEFORMING THE MATERIAL NOT MORE THAN APPROXIMATELY 85% AT A TEMPERATURE OF FROM 150*F ABOVE THE MD30 TEMPERATURE, THEREBY C. DECREASING THE AMBIENT TEMPERATURE STABILITY OF THE AUSTENITE WHEREIN IT FORMS MARTENSITE AT RAPID RATE UPON BEING COLD WORKED.
Claim 3
Dependent Claim
76 words
A process for conditioning type 18-8 stainless steel for subsequent cold deforming comprising the steps of: a. annealing the material in a temperature range of from about 1,500*F to about 2,100*F; and, b. mechanically deforming the material not more than approximately 85% at a temperature of from 200*F to 400*F above the Md30 temperature, thereby c. decreasing the ambient temperature stability of the austenite wherein it forms martensite at a rapid rate upon being cold worked.
Claim 4
Dependent Claim
76 words
A process for conditioning type 18-8 stainless steel for subsequent cold deforming comprising the steps of: a. annealing the material in a temperature range of from about 1,500*F to about 2,100*F; and, b. mechanically deforming the material not more than approximately 85% at a temperature of from 200*F to 400*F above the Md30 temperature, thereby c. decreasing the ambient temperature stability of the austenite wherein it forms martensite at a rapid rate upon being cold worked.
Claim 5
Dependent Claim
77 words
A process for strengthening Type 18-8 stainless steel comprising the steps of: a. annealing the material in a temperature range of from about 1,500*F to about 2,100*F. b. mechanically deforming the material not more than approximately 85% at a temperature of from 150*F to 500*F above the Md30 temperature as defined in the specification; and c. cold deforming the material at room temperature at least 60% to produce a tensile strength of at least 325,000 psi therein.
Claim 6
Dependent Claim
77 words
A process for strengthening Type 18-8 stainless steel comprising the steps of: a. annealing the material in a temperature range of from about 1,500*F to about 2,100*F. b. mechanically deforming the material not more than approximately 85% at a temperature of from 150*F to 500*F above the Md30 temperature as defined in the specification; and c. cold deforming the material at room temperature at least 60% to produce a tensile strength of at least 325,000 psi therein.
Claim 7
Dependent Claim
19 words
The process of claim 3 wherein the mechanically deforming is accomplished at 200*F to 400*F above the Md30 temperature.
Claim 8
Dependent Claim
13 words
The conditioned Type 18-8 stainless steel formed by the process of claim 1.
Claim 9
Dependent Claim
22 words
A high strength 18-8 stainless steel having a tensile strength of at least 325,000 psi made by the process of claim 3.
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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |