HEAT INPUT EFFECT OF THE FCAW PROCESS ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF STRUCTURAL STEEL JOINTS

Flux-cored wires are commonly used in structural and pipeline welding, shipbuilding, offshore constructions, petrochemical power generation industries. The higher heat inputs the multi-pass welding result shorter production time while considerably changing properties of welded joint. In this study, robotic flux cored arc with varying (between 0.56-2.52 kJ/mm) was performed to determine effect input on weld microstructure, hardness, tensile properties, impact toughness steel joints. Results exhibited that decrease from 2.52 0.56 kJ/mm changed majority microstructure polygonal ferrite acicular ferrite. Furthermore, increased by 56%, 37%, 47% yield strength, hardness values, respectively, decreasing 30% 15% elongation Charpy test results, respectively. Moreover, all joints displayed a satisfying value than requested 47 J, even at temperature -50 °C. Finally, it can be concluded optimum results were obtained 1.26 kJ/mm, considering minimum requirements AWS A5.20 standard expectations applications.