Pipelines are used to transport gas, water, oils, and other liquids from one point to the other. Note that there is a specific difference between pipe welding and pipeline welding. Pipe welding normally refers to the welding of pipes inside chemical plants and oil refineries. Inside the plant a varying range of pipe sizes and materials require welding. On the contrary, pipeline welding concentrates on welding pipes of uniform size and material spread over hundreds of kilometers. Pipeline welding is an indispensable part in all kinds of devices and equipments, the quality of pipeline welding directly affects the normal operation, pipeline welding is a very important activity in pipeline construction.