Per: lucas menezes de souza (UENF), Camila Vasconcellos Fernandez (UENF), Elaine Cristina Pereira (UENF), Stephanie Carvalho Mendes Lopes (UENF)
Abstract:
AISI1065 carbon steel is a metallic alloy widely used in civil construction and as a component in the tensile reinforcement of flexible pipelines used by the offshore industry. In some circumstances, this steel requires repairs, using the welding process. Resistance welding is the most applied method for carbon steel, using electric current to generate heat to join discontinuities. This procedure can change the properties of the microstructure due to the increase in stress concentration, increasing the hardness in the weld region. Although it is a high tensile strength alloy, this steel is subject to degradation processes such as electrochemical corrosion, which reduces the material's resistance. In this work, a study was carried out on the corrosion resistance of AISI 1065 carbon steel after the resistance welding process. Resistance welding was carried out with a voltage of 2.5 V and a current of 10337 A on 10 steel test specimens divided into two groups of 5 samples. Then, the samples underwent heat tempering treatment. Subsequently, metallographic characterization of the metal was carried out to evaluate the microstructure. Corrosion tests were carried out on samples with and without welding in order to compare the impact of the corrosive medium of 3.5% NaCl. To analyze the mechanical properties, tensile, hardness and microhardness tests were carried out. It was found, after carrying out the tests, that welding is a factor that alters the mechanical properties of AISI 1065 carbon steel, causing the formation of pores that caused a reduction in the hardness of the welded joints.