Welding is a crucial part of any fabrication and construction activities for Oil and Gas industries. Achieving the welding with the highest quality possible is the main objective of all companies in this field. Therefore, great attention was given for selection of the proper welding process and optimize the variables to achieve welding quality that meets or exceeds customer requirements. In this paper we will focus on the selection of Gas Metal Arc Welding (GMAW) process and its characteristics. We will also explain in details one of the lessons learned in how to control the high weld rejection rate to the minimum possible by utilizing the proper investigation tools and implementing the immediate corrective actions