Selecting the Appropriate Filler Metal to Join HSLA-100 Steel by Gas Tungsten Arc Welding Process

In the present research, the welding of HSLA-100 steel was performed using ER100S-G, ER120S-G, and ER2209 filler rods via the gas tungsten arc welding process. The microstructure, mechanical properties, erosion behavior, and corrosion resistance of all three weld metals were evaluated and compared. Microstructural investigations showed that the ER100S-G weld metal microstructure comprised grain boundary, widmanstatten and acicular ferrites with a continuous network of M/A constituents (mainly the blocky type) at grain boundaries, and that the microstructure of ER120S-G weld metal consisted of acicular, polygonal, and quasi-polygonal ferrites with finely dispersed M/A constituents (mainly the stringer type) at grain boundaries and within the grains. The microstructure of the ER2209 weld metal was also comprised of two phases: ferrite (47%) and austenite (53%). The mechanical tests demonstrated that the ER120S-G weld metal had the highest strength and hardness and that the ER2209 weld metal had the highest impact energy. Moreover, the erosion test results showed that the ER120S-G and ER100S-G weld metals had a better erosive behavior at the 90 degrees impact angle and that the ER2209 and ER120S-G weld metals revealed better behaviors at 30 degrees impact angle. In addition, it was found that all weld metals have lower erosion rates than the base metal. The corrosion test results also disclosed that the ER2209 weld metal had the highest uniform and pitting corrosion resistance.