The welding procedure I chose to write about is GTA welding in the 1G horizontal rolled pipe position. I have explained how to prepare the weld joint, set up the welding process and how to physically weld up the joint from beginning to end.
On a 1G rolled pipe procedure the ends of the pipe are to be grooved before welding. Doing this you are insuring yourself a sound weld. The type of groove prepared on the end of the pipe depends on the application, pipe material, and thickness. V groove and U grooves are the 2 most common found in the field because they are easily done with flame cutting. The grooves are to be prepared with a 37 ½ degree bevel leaving a 1/16in to 1/8in root face. When both sides are prepared they should form a 75-degree V groove. The reason for doing this angle is for good visibility and a minimal amount of filler metal to fill the groove. The grinding or machining the sharp end on the end of the bevel creates a root face. The root face is a small flat surface at the root of the groove. If you fail to remove the root edge it can result in burning back the material and cause a large keyhole to be filled. A concave root or suck back face often results when you do that.
Before you assemble the joint you will need to ensure yourself that the metal is clean, smooth, uniform and free of any contaminants. To remove possible contamination you can grind, wire brush, or use filing. The cleaning process chosen needs to be done 1in or more, on the inside and outside of the pipe.
The pipe needs to be tacked together with a root opening of 3/32 to 1/8. There should be 4 or more evenly spaced tacks around the pipe. These tacks should be located so that they do not interfere with the starting or stopping of the root pass. Starting and stopping on a tack can cause poor penetration.
When setting up a GTA welder you will need a GTA welder, remote control welding torch, gas flow meter, gas source, tungsten, nozzle, collet, collet body, cap, and any...