Análise da influência dos metais de adição na soldagem de chapas de aço microligado galvanizadas soldadas pelo processo GMAW robotizado

Abstract

The addition of alloying elements has the main purpose to control the microstructure of the material, reflecting in its microscopic, macroscopic, physical, mechanical and electrical properties, allowing the material to perform specific functions. The present work evaluates the influence of silicon (Si) and manganese (Mn) on the macrostructure of weld beads executed in high strength and low alloy microalloyed steels galvanized sheets. Robotized Gas Metal Arc Welding (GMAW) welding was used with 82% Argon/18% CO2 gas mixture, and two wire types (AWS ER70S-6 and ER70S-3) whose main difference is their silicon and manganese contents. Test specimens were extracted from a standard series production product of a car component. Possible changes in the output parameters of the welding power source (Current and Voltage) for the same wire feeding speed and weld bead shape parameters (penetration, length of fillet legs and effective throat size) were evaluated. Weld sections were analyzed by macrographic images generated by the Welding Expert 5 equipment and data collection during the experiment. It was evidenced a different dynamic response of the welding source when the wire was changed from ER70S-6 to ER70S- 3. The macrographic images revealed a considerable difference between the weld bead geometries performed with each wire. The weld beads executed with ER70S-3 wire presented a smaller formation of internal porosities in relation to weld beads welded with the wire ER70S-6.