Uma prospecção de variantes MIG/MAG avançadas com vistas à recuperação ou aumento de espessura de chapas de aço de embarações

Abstract

This study investigates advanced MIG/MAG welding process variants aimed at thickness increment in ASTM A36 steel plates through side-by-side parallel bead overlays. It employs ER70S6 wire and a shielding gas mixture of 85% argon and 15% carbon dioxide, testing variants such as controlled short-circuit, short-circuit with electromechanical control, and adaptive pulsed modes. The research examines the behavior of these variants by varying wire feed speed (WFS) and, subsequently, the Contact Tip to Workpiece Distance (CTWD), while monitoring electrical parameters, wire feed speed, and surface morphology. Metal transfer stability is evaluated using oscillograms and high-speed filming. An equation is developed to estimate welding parameters for predetermined thickness increments. The study demonstrates that the short-circuit variant with electromechanical control, commercially known as Cold Metal Transfer (CMT), excels at high wire feed speeds due to its robust transfer control and lower welding energy. It finds that the available penetration controls fail to maintain constant penetration with CTWD variation under the evaluated conditions. The study concludes that CMT stands out as the most promising variant for this application, offering robust control, uniform deposition, and low welding energy.