US4885455A
Expired / Lapsed
US
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Process for terminating closed through-hole plasma arc welding
Assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Filing: 1988-08-18
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Granted: 1989-12-05
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Expires: 2008-08-18
Abstract
Abstract To terminate welding, the mean energy of the arc is first reduced to obtain plugging of the hole, then this energy is briefly increased before again being decreased. Application to plasma arc welding of carbon steels.
Inventors
- 👤 Jean-Pierre Schultz
- 👤 Eric Verna
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:02
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/02; B23K10/00; B23K10/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
59 words
In a process for terminating through-hole plasma arc closed welding during which a plasmagenic gas passes through said hole, the improvement wherein the mean arc energy is continuously decreased until the hole is plugged, then said mean arc energy is increased while the plasmagenic flow rate is decreased before said mean arc energy is again continuously decreased to zero.
Claim 2
Dependent Claim
59 words
In a process for terminating through-hole plasma arc closed welding during which a plasmagenic gas passes through said hole, the improvement wherein the mean arc energy is continuously decreased until the hole is plugged, then said mean arc energy is increased while the plasmagenic flow rate is decreased before said mean arc energy is again continuously decreased to zero.
Claim 3
Dependent Claim
25 words
Process according to claim 1, characterized in that the increase of the mean energy of the arc continues longer than said reduction of flow rate.
Claim 4
Dependent Claim
28 words
Process according to claim 1, characterized in that during the first period of reduction of mean energy of the arc, the speed of advance of welding is reduced.
Claim 5
Dependent Claim
40 words
Process according to claim 1, characterized in that, after the period of mean energy increase of the arc, and during the time the mean energy of the arc is again decreased, the welding torch is moved away from the piece.
Claim 6
Dependent Claim
28 words
Process according to claim 1, characterized in that, during the time the mean energy of the arc is again decreased, addition metal is added to the weld zone.
Claim 7
Dependent Claim
31 words
Process according to claim 1, characterized in that at the beginning of the period of increase of the mean energy of the arc, the flow rate of plasmagenic gas is decreased.
Claim 8
Dependent Claim
29 words
Process according to claim 1, characterized in that the increase of the mean energy of the arc continues at least twice as long as said reduction of flow rate.
References Cited (Backward Citations)
FR1579377A
Cited
JPS50975A
Cited
US4195216A
Cited
GB2074071A
Cited
DE3405242A1
Cited
EP0256525A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-04 | 1993-06-05 | 1993-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-04 | 1997-06-05 | 1997-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-04 | 2001-06-05 | 2001-12-05 | $7700.00 | Window Closed / Lapsed |