摘要 |
A method of applying a welded overlay to the interior surface of curved hollow articles such as 90 degree elbows utilizing a submerged arc welding gun curved to follow the radius of the hollow article and comprised of an elongated cylindrical body (27) and a curved weld head (10), welding tip holder (24) and welding tip (28) and incorporating a flux conveying system (16), (18) and (20) and a plurality of air release slots (22) by which the flow of flux to the weld area is controlled. A first series of overlapping welds is applied longitudinally to the interior surface of the hollow article to cover 90 degrees of the surface therein. The article is rotated and a second series of overlapping welds are applied 180 degrees from the first series and again covering 90 degrees of the interior surface. A third series of overlapping welds are applied beginning at either of the end welds of the first series and covering 90 degrees of the interior surface. A forth and final series of overlapping welds are applied, 180 degrees from the third series, covering the remaining 90 degrees of the interior surface.
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