Circumferential welding is common practice in pipe fabrication where welding takes place in circular form. It can be performed using all types of arc welding process and even the solid state welding technique can also be used for joining of large pipes for example friction stir welding.
The processes which are popular today in fabrication industries are; Shield metal arc welding, Metal inert gas welding, Flux core arc welding, Tungsten Inert Gas Welding, Submerged arc welding, Electroslag welding and Friction Stir welding. They have their own advantageous features and limitations for several range of applications. Some are totally automatic and machine operating while some are manually manipulated by welders and operators. Automatic processes are limited to simple joint configurations and positions while manually controlled processes can be applied to complex joints and repairs.
Type of arc welding which has wide range applications in welding world is; Tungsten Inert Gas process where arc is produced between electrode and work metal, under the shield of inert gas and just like soldering, an external filler rod is added to fill the joint. This process is manually manipulated by a welder and hence many artistic results are produced like walking cups in the weldment. Cups looks like ripples made in the molten weld metal which solidify to give an elegant look to the viewer. It also helps to provide desired mechanical and metallurgical properties e-g reinforcement, strength, complete fusion etc.
