Enhanced arc control for magnetically impelled butt welding
First Claim
1. An arc control method for magnetically impelled butt welding, comprising:
- bringing ends of tubulars to be welded adjacent each other for an initial positioning of major longitudinal axes to create a gap therebetween;
producing a condition to create an arc that crosses said gap;
applying a magnetic field to said gap;
moving said arc around on said ends of said tubulars;
angularly skewing said major longitudinal axis of at least one of said tubulars from said initial positioning to obtain a different relative positioning between said tubulars to control the path of said arc on said ends of said tubulars; and
butt welding said tubulars.
1 Assignment
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Accused Products
Abstract
Tubulars are joined for subterranean borehole use in the production of hydrocarbons by a technique of magnetically impelled arc butt (MIAB) welding. Large casing can be accommodated and the weld quality is maintained with control over the pattern of arc movement on the end walls by virtue of relative movements of the tubulars as the arc is generated and the magnetic field is applied. One or both tubulars can be manipulated relatively in a variety of direction to control the movements of the arc as the magnetic field induces circular arc movement along the end walls of the tubulars to heat up the ends to the temperature needed to effectively fuse the wall ends together. Movement can be rotational or axial about a fixed axis or lateral with respect to the axes both with and without skewing of the axes. The movements can be combined to obtain the desired track.
14 Citations
23 Claims
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1. An arc control method for magnetically impelled butt welding, comprising:
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bringing ends of tubulars to be welded adjacent each other for an initial positioning of major longitudinal axes to create a gap therebetween; producing a condition to create an arc that crosses said gap; applying a magnetic field to said gap; moving said arc around on said ends of said tubulars; angularly skewing said major longitudinal axis of at least one of said tubulars from said initial positioning to obtain a different relative positioning between said tubulars to control the path of said arc on said ends of said tubulars; and butt welding said tubulars. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification