AUTOMATIC PIPE WELDING: REAL-TIME CONTROL OF WELD SIZE, SHAPE, AND PENETRATION USING THE ELECTRODYNAMIC ARC AND PUD-DLE CONTROL SYSTEM

AUTOMATIC PIPE WELDING, FOR BOTH NEW CONSTRUCTION AND REPAIRWELDING, CURRENTLY DEPENDS UPON OPERATOR SKILL AND OTHER CONTROLS TO ASSURE SOUND WELDED JOINTS. ADDITIONAL EXPENSESSUCH AS X-RAY INSPECTION COMBINE TO MAKE THE COSTS OF ANY NECESSARY REWORK OF WELDED PIPES PROHIBITIVE. ELECTRODYNAMIC ARC AND PUDDLE CONTROL (EDAP) IS A THROUGH-THE-ARC METHOD OF SENSING BOTH WELD PUDDLE SIZE AND PENETRATION, WITH REAL-TIME CONTROL. THE SYSTEM DOES NOT REQUIRE ACCESS FROM THE BACK SIDE NOR EXTERNAL SENSORS IN THE HARSH ENVIRONMENT OF THE WELDING ARC. POLY-PULSE WELDING (SQUARE WAVE MILLI-PULSE WITH SUPERIMPOSED MICROPULSE), BY SELECTED COMBINED FREQUENCIES, WILL CHANGE WELD BEAD SHAPE, I.E., A NARROW PENETRATING BEAD FOR ROOT PASSES OR A WIDE SMOOTH BEAD FOR THE CAP PASS. THIS TECHNIQUE ELIMINATES THE NEED FOR CUMBERSOME MECHANICAL OSCILLATORS ON THE WELD HEAD AND IS PROGRAMMABLE. THE IDEALMETHOD FOR THE HIGHEST QUALITY OF PIPE WELDING IS TO COMBINETHE EDAP CONTROL WITH THE POLY-PULSE PROCESS. THIS WILL PROVIDE, FOR THE FIRST TIME, REAL-TIME CONTROL OF THE FINAL WELDED JOINT THAT IS BOTH AUTOMATIC AND PROGRAMMABLE. THIS RESEARCH PROJECT SHOULD PROVE THE FEASIBILITY OF THIS NEW CONCEPT.