US3864542A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Grain refinement control in tig arc welding
Assignee: National Aeronautics and Space Administration
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Filing: 1973-11-13
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Granted: 1975-02-04
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Expires: 1993-11-13
Abstract
Abstract A method for controlling grain size and weld puddle agitation in a tungsten electrode inert gas welding system to produce fine, even grain size and distribution is disclosed. In the method the frequency of DC welding voltage pulses supplied to the welding electrode is varied over a preselected frequency range and the arc gas voltage is monitored. At some frequency in the preselected range the arc gas voltage will pass through a maximum. By maintaining the operating frequency of the system at this value, maximum weld puddle agitation and fine grain structure are produced.
Inventors
- 👤 James C Administrator Fletcher
- 👤 William F Iceland
- 👤 Edwin L Whiffen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:29
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/09; B23K9/095; B23K2101/00; B23K2101/04; B23K2101/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
148 words
A method for controlling grain size and weld puddle agitation in an inert gas atmosphere welding operation, comprising the steps of: supplying DC voltage pulses between a welding electrode and a pair of members to be welded in the presence of an inert gas atmosphere, said DC voltage pulses being of equal time duration; sensing the voltage in the electric arc formed in said inert gas between said electrode and said member being welded; varying the operating frequency of said DC voltage pulses from a lower frequency to a higher frequency over a preselected frequency range; selecting the frequency in said preselected frequency range which produces a maximum value of said sensed arc gas voltage; and maintaining the operating frequency at said selected frequency producing said maximum value of arc gas voltage to thereby produce maximum weld puddle agitation and fine, uniform grain size in the weld zone.
Claim 2
Independent Claim
148 words
A method for controlling grain size and weld puddle agitation in an inert gas atmosphere welding operation, comprising the steps of: supplying DC voltage pulses between a welding electrode and a pair of members to be welded in the presence of an inert gas atmosphere, said DC voltage pulses being of equal time duration; sensing the voltage in the electric arc formed in said inert gas between said electrode and said member being welded; varying the operating frequency of said DC voltage pulses from a lower frequency to a higher frequency over a preselected frequency range; selecting the frequency in said preselected frequency range which produces a maximum value of said sensed arc gas voltage; and maintaining the operating frequency at said selected frequency producing said maximum value of arc gas voltage to thereby produce maximum weld puddle agitation and fine, uniform grain size in the weld zone.
Claim 3
Dependent Claim
45 words
The method of claim 1 wherein the step of sensing the voltage in the electric arc formed in said inert gas is performed by monitoring said voltage on a cathode ray oscilloscope having a frequency response characteristic sufficiently broad to cover said preselected frequency range.
Claim 4
Dependent Claim
35 words
The method of claim 1 wherein the step of varying the operating frequency of said DC voltage pulses is performed by varying said operating frequency in the preselected frequency range of zero to 10 kilohertz.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein all the steps are performed at a plurality of points along the juncture of said members being welded.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein said welding system employed is a tungsten electrode inert gas welding system.
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) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |