Effect of welding processes on mechanical and microstructural properties of S275 structural steel joints

Abstract

Abstract S275 structural steel is a popular low carbon steel type that can be used in many different general engineering and structural applications. These steels are widely used in steel construction, maintenance, machinery and manufacturing industries. Welded joints of this steel used in the mentioned industrial areas are important. In this study, 10-mm thick S275 structural steel sheets were joined by using gas metal arc welding (GMAW) and flux cored arc welding (FCAW) methods. Tensile, bending, and hardness tests were performed to determine the mechanical properties of the welded samples. In addition, metallographic investigations were carried out to determine the microstructural properties of the weld zones. As a result of the microstructural studies, it was found that different structures such as grain boundary ferrites, polygonal ferrites, Widmanstatten ferrites and acicular ferrites are formed in the weld metal and coarse-grained region. It was determined that the hardness of the weld metal was higher than HAZ and base metal in all welding parameters. The highest tensile and bending strengths were obtained from those samples joined by using the FCAW method. As a result of the tensile test, separation occurred in the transition region between the weld metal coarse-grained regions.