Resumen en inglés

The effect of the heat input generated by the GMAW welding process and protective gas 90Ar10CO2 on the fracture toughness of the different welding zones in the joints of ASTM A572 Gr 50 steel, which is a high-quality steel, was evaluated. High strength and low alloy (HSLA). Initially, the characterization of the base metal was carried out through techniques such as: optical emission spectrometry, optical microscopy, tensile tests, hardness tests and fracture toughness tests, with these data on chemical composition, microstructure, stress creep, hardness and fracture toughness values, respectively. Subsequently, the welding of the 400mmX150mmX6,35mm steel plates was carried out, by means of GMAW, using different heat inputs (high and low). From the welding coupons, the different welding zones were identified by macrography; and the phases in said zones were identified by means of metallography and X-ray diffraction. Then the fracture toughness test was carried out on specimens with the pre-crack located in the thermally affected zone (HAZ) and in the weld metal zone, welded joints. It was evidence that the fracture toughness is correlated with the microstructural changes in the ASTM A572 Gr 50 steel product of the thermal inputs of the GMAW welding process, this has an impact on the resulting phases; as well as the size, location and composition of the precipitates.