Welding is the way that pieces of metal are permanently joined together. Almost everything around you was either welded or made by some piece of equipment that was welded, from small piping systems to giant skyscrapers. Due to the multiple demands or applications of welding, different types of welding processes are used to bring about the best result. And there is a large variety of welding methods to choose from, there are four which are most commonly used and important welding services.