Method and device to build-up, clad, or hard-face with minimal admixture
AssigneeLincoln Global, Inc.
InventorsSteven R. Peters, Michael J. Morlock, Bruce E. Fulmer, James E. Hearn
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Abstract
An electric arc device and methods to build up, clad, join, or overlay an alloyed metal onto a parent metal with minimal admixture. The methods employed in the electric arc device provide a high frequency waveform with a high amplitude pulse, a low amplitude background current, and a special shorting routine, to alleviate the problem of generating too much ad-mixture. A fast transition from a peak current level to a background current level along with a shorting response and a plasma boost pulse reduces the droplet size and reduces the heat input required to achieve good welding performance.
Claims19
A method of cladding or hard-facing an alloyed metal onto a parent metal with minimal admixture by generating a series of electric arc pulses between an advancing electrode comprising said alloyed metal and a workpiece comprising said parent metal, said method comprising:
- (a) increasing an output current level above a background current level over a first time segment;
- (b) regulating said output current level to a peak current level over a second time segment;
- (c) decreasing said output current level from said peak current level toward said background current level in an attempt to induce a first short of molten metal between said advancing electrode and said workpiece;
- (d) regulating said output current level to said background current level;
- (e) remaining at said background current level when said first short is not detected as occurring;
- (f) when said first short is detected as occurring, ramping said output current level above said background current level, until said first short is cleared at a ramped output current level;
- (g) generating a plasma boost pulse immediately upon clearing said first short by pulsing said output current level above said ramped output current level, starting when said first short is cleared, over a third time segment to prevent a second short from occurring;
- and
- (h) repeating steps (a) through (g) at a pre-defined pulse repetition rate for said series of pulses.
An electric arc device used for cladding or hard-facing an alloyed metal onto a parent metal with minimal admixture by generating a series of electric arc pulses between an advancing electrode comprising said alloyed metal and a workpiece comprising said parent metal, said electric arc device comprising:
- a waveform generator for repeatedly generating output welding waveforms having:
- a peak pulse segment having an output current level regulated to a peak current level and a pulse width, wherein said peak current level is above a background current level, and wherein said output current level is reduced to about said background current level at a first rate for inducing a first short of molten metal between said advancing electrode and said workpiece,
- a short clearing current segment ramping said output current level above said background level to clear said first induced short, wherein said first induced short is cleared at a ramped output current level, and
- a plasma boost segment pulsing said output current level above said ramped output current level, starting immediately when said first induced short is cleared, to prevent a second short from occurring after said first short.
Dependencies are inferred from the claim text.