Patent US3844846A successfully refreshed from Google Patents.
US3844846A
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Desensitization of alloys to intergranular corrosion
Assignee: Boeing North American Inc
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Filing: 1973-06-01
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Granted: 1974-10-29
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Expires: 1993-06-01
Abstract
Abstract Intergranular corrosion is prevented in sensitization susceptible alloys by severely shot peening the alloy surface so that the structure of the original grains at the surface is broken up and grain boundaries are no longer continuous, this peening treatment being done prior to exposure of the alloy to the sensitizing temperature. The method is preferred for the treatment of susceptible austenitic chromium-nickel-iron alloys, particularly the austenitic stainless steels of the 18-8 type.
Inventors
- 👤 W Friske
- 👤 J Page
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:03
CPC Classifications
C; C21; C21D; C21D7/00; C21D7/02; C21D7/04; C21D7/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
53 words
THE METHOD OF DESENSITIZING AN ALLOY SUSCEPTIBLE TO INTERGRANULAR CORROSION FOLLOWING EXPOSURE TO A SENSITIZING TEMPERATURE WHICH COMPRISES SEVERLY SHOT PEENING A SURFACE OF THE ALLOY WITH SUFFICIENT INTENSITY SO AS TO BREAK UP THE GRAN STRUCTURE AND ELIMINATE CONTINOUS GRIN BOUNDARIES THEREOF PRIOR TO EXPOSURE OF SAID ALLOY TO SAID SENSITIZING TEMPERATURE.
Claim 2
Independent Claim
53 words
THE METHOD OF DESENSITIZING AN ALLOY SUSCEPTIBLE TO INTERGRANULAR CORROSION FOLLOWING EXPOSURE TO A SENSITIZING TEMPERATURE WHICH COMPRISES SEVERLY SHOT PEENING A SURFACE OF THE ALLOY WITH SUFFICIENT INTENSITY SO AS TO BREAK UP THE GRAN STRUCTURE AND ELIMINATE CONTINOUS GRIN BOUNDARIES THEREOF PRIOR TO EXPOSURE OF SAID ALLOY TO SAID SENSITIZING TEMPERATURE.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said alloy is selected from austenitic Cr-Ni-Fe alloys.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein said alloy is an austenitic stainless steel of the 18-8 type.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein the grain boundary and grain structure disruption of said surface extends to at least about to 1-5 mils below the surface of said alloy.
Claim 6
Dependent Claim
55 words
The method of claim 4 wherein a surface of a stainless steel alloy of the 18-8 type is shot peened to desensitize it to intergranular corrosion, the required degree of shot peening being determined by a nondestructive test reading prior calibrated against metallographically examined samples of said alloy following shot-peening, sensitization and corrosive treatment thereof.
Claim 7
Dependent Claim
19 words
The method of claim 5 wherein said nondestructive test reading is obtained utilizing ferrite measuring or eddy-current measuring instrumentation.
Claim 8
Dependent Claim
21 words
The method of claim 4 wherein said disruption of said surface is obtained by utilizing ceramic beads for the shot peening.
References Cited (Backward Citations)
US2527287A
Cited
US2795519A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |