Manual metal arc welding of dissimilar 30MnB5 and S 235 low alloyed steels for agricultural applications

Abstract

Abstract In agricultural mechanization industry, different types of materials are assembled with each other to establish agricultural machine systems. However, the necessity of joining dissimilar materials used in the same machine system may cause some problems. Joining two different materials by welding and selecting the most appropriate weld metal (electrode) for this is a very difficult problem. The increasing importance of the economic factors in today’s industry requires both the use of dissimilar materials in agricultural mechanization and the production of longer-lasting agricultural machines, thus making it necessary to use dissimilar steels in agricultural mechanization systems. Therefore, it is important to apply a welding process to dissimilar steels used in agricultural mechanization. In this study, 30MnB5/S235 steel pairs were joined by the manual metal arc welding (MMAW) method using different covered electrodes. In order to determine the mechanical properties of the welded samples, hardness, bending, and impact tests were carried out. In addition, visual inspection to the weld seams, liquid penetrant testing, and metal-lographic examinations to determine the microstructural properties were conducted. As a result of the microstructure studies, structures such as grain boundary ferrite, Widmanstätten ferrite, acicular ferrite, bainite, and martensite were determined in the weld metal and HAZs. As a result of the hardness test, the highest hardness values were determined in HAZs on the side of 30MnB5 steel. As a result of the bending test, the highest mechanical properties were obtained in the weld seams made with basic flux-cored wire. As a result of the notch impact test, the highest mechanical properties were obtained in the weld seams made with basic flux-cored wire, after the base metals.