Method for orbital welding using a pulsed current

1. A method for the orbital welding of tubular elements held in abutment comprising the steps of:

a) striking an arc at a strike point with an orbital welder between an electrode and a seam formed by a first tubular element and a second tubular element held in abutment within a fixture, said first tubular element having a wall, said second tubular element having a wall;

b) initiating an orbit of said electrode around an abutment of said first tubular element and said second tubular element;

c) adjusting the current of said arc in a pulsed manner from a maximum current to a minimum current at a set frequency;

d) decreasing said maximum current in a generally continuous manner as said orbit of said electrode progresses from said strike point, the rate of decrease of said maximum current having a generally inverse relationship to the rate of increase in temperature experienced by said tubular elements;

wherein an average current is generally decreasing continuously over time;

and wherein said minimum current is held generally constant;

and wherein an average temperature of said tubular elements is maintained within a predetermined range;

and wherein a resulting weld bead is fully penetrated through said walls of said first tubular element and said second tubular element.

2. The method of claim 1 further comprising the steps of:

decreasing rapidly said average current in a generally continuous manner at the conclusion of at least a first orbit of said electrode around said seam formed between said first tubular element and said second tubular element;

disengaging said arc.

3. A method for the orbital welding of tubular elements held in abutment comprising the steps of:

a) striking an arc at a strike point with an orbital welder between an electrode and a seam formed by a first tubular element and a second tubular element, held in abutment within a fixture, said first tubular element having a wall, said second tubular element having a wall;

b) initiating an orbit of said electrode around an abutment of said first tubular element and said second tubular element;

c) adjusting the current of said arc in a pulsed manner from a maximum current to a minimum current at a set frequency;

d) decreasing said maximum current in a generally continuous manner as said orbit of said electrode progresses from said strike point, the rate of decrease of said maximum current having a generally inverse relationship to the rate of increase in temperature experienced by said tubular elements;

e) decreasing said minimum current in a generally continuous manner as said orbit of said electrode progresses from said strike point, the rate of decrease of said maximum current having a generally inverse relationship to the rate of increase in temperature experienced by said tubular elements;

wherein an average current is generally decreasing continuously over time;

and wherein said minimum current is held generally constant;

and wherein an average temperature of said tubular elements is maintained within a predetermined range;

and wherein a resulting weld bead is fully penetrated through said walls of said first tubular element and said second tubular element.

4. The method of claim 3 further comprising the steps of:

decreasing rapidly said average current in a generally continuous manner at the conclusion of at least a first orbit of said electrode around said seam formed between said first tubular element and said second tubular element;

disengaging said arc.

5. A method for the orbital welding of tubular elements held in abutment comprising the steps of:

a) striking an arc at a strike point with an orbital welder between an electrode and a seam formed by a first tubular element and a second tubular element, held in abutment within a fixture, said first tubular element having a wall, said second tubular element having a wall;

b) initiating an orbit of said electrode around an abutment of said first tubular element and said second tubular element;

c) adjusting the current of said arc in a pulsed manner from a maximum current to a minimum current at a set frequency, combination of said maximum current and said minimum current forming an average current;

d) decreasing said average current in a generally continuous manner as said orbit of said electrode progresses from said strike point, the rate of decrease of said maximum current having a generally inverse relationship to the rate of increase in temperature experienced by said tubular elements;

wherein an average temperature of said tubular elements is maintained within a predetermined range;

and wherein a resulting weld bead is fully penetrated through said walls of said first tubular element and said second tubular element.

6. The method of claim 5 further comprising the steps of:

decreasing rapidly said average current in a generally continuous manner at the conclusion of at least a first orbit of said electrode around said seam formed between said first tubular element and said second tubular element;

disengaging said arc.