The investigation of influences on primer coating processes on weldability of S235 JR material

In this study, robotic MAG welding and submerged arc welding methods were separately applied for coated (shopprimer) and uncoated S235JR structural steel with diferent thicknesses and the effects of these applications on the mechanical and microstructure properties of the materials were investigated. In the experimental studies, the first group materials were used as they are, second group materials were sandblasted at Sa 2 ½ degree, to the materials they are in the other group 25 µm, 50 µm and 75 µm coatings were applied. Surface conditions and coating thicknesses were selected as the variable parameters. With the examination of the radiography films, it was observed that the surface conditions affects the weld joint. As a result of the study, it was observed that altered coating thicknesses caused defects in the welding zone. It was determined that the coating thicknesses partially affect the mechanical properties and the highest hardness values occur in the weld metal zone in the all samples. According to the tensile and bending test results, unsuitable results were just obtained in the material groups coated as 75 µm thickness and welded by MAG and submerged welding methods. As a result of the impact tests unsuitable results were just obtained in material groups welded by submerged arc welding method and coated as 75 µm thick. The results were verified by the surface fructure, SEM and EDS studies.