Cup Walking Considerations in Welding Technology
As you are aware, TIG welding comprises of the electrode, current, filler material, and the electrode holder like any other welding procedure.The electrode consists of some type of Tungsten by which the electric current is carried to the metals that are to be fused together. Then the electricity and gas are there for blending together in this process.
The traditional methods of TIG welding demands maintenance of a consistent arc length and to dab filler metal in the weld puddle. This can be tedious and frustrating for the person. Continuously changing angles for the dynamics of welding on pipe is another impediment. The welding person is hard put to create quality welds under these conditions.
But using the cup walking technique is tremendously helpful. In this technique, the nozzle of the TIG torch rests right on the pipe with the filler metal placed in the groove. There is decidedly more arc stability and greater comfort, permitting the operator to change positions more easily. The fact is welding persons can use cup walk method on any type of pipe or other materials barring aluminum as the melting temperature of aluminum is low.
The specific power source settings for cup walking depends largely on the thickness of the material being welded, inter-pass temperatures and the heat input requirements of the given weld procedure. Operators need higher amperage settings for thicker materials, but for the open groove TIG joints present on pipe, setting the power source in a range of 90 to 110 amps works well on most materials.
Walking the cup is a technique should be welcomed by all pipe fitters as it enables the welder to travel long distances uninterruptedly and thus uniformly progress the weld. But some TIG welders avoid walking the cup technique mostly because they are ignorant of this unique application. Of course, there may be occasions when you will not be able to walk the cup.
Sometimes the slowness of the cup walking technique (due to cup changing) may influence the operators to avoid the process. However, it is to be noted that the advantages of walking the cup far outweigh the potential problems. With adequate training and practice, learning to walk-the-cup can become aninvaluable skill and application for use in a wide range of industries.
Walking the cup can be immensely advantageous for two reasons. Firstly, a pipe can get terribly hot and if the welder is somewhat negligent, he can burn his rig hand fingers - the key hand one uses to operate the welding rig. Secondly, there will be times when the welder can cover more ground by walking the cup than by manipulating the weld puddle by hand alone. If a professional welder can become proficient in walk the cup method, he can certainly add this to his armoury of welding techniques.
But the truth is cup walking technique is highly specified and requires intensive practice and skill on the part of the operator. For walking the cup, it is critical to completely align the pieces of pipe and tack them up to make certain that they do not shift while welding. Techniques for tacking also depend on the size of pipes. After tacking, the operators should grind the tack to a feathered edge to assure that solid tie-in is achieved during the root pass procedure. It is necessary to choose the appropriate diameter of filler metal for the specific groove joint.