Estudio del efecto de la protección catódica en la corrosión de placas y juntas soldadas a tope de aceros A-36 y SA-516 grado 70.

Abstract

In this titling work, the implementation of the cathodic protection method by sacrificial anodes was carried out, on butt welded joint plates of steels A-36 and SA-516 grade 70, using aluminum as a sacrificial anode, for this way avoid the formation of the phenomenon of corrosion, through an accelerated test in a salt spray chamber, the same one that was carried out under the ASTM B 117 standard. The evaluation of the degradation of the surface layer of the material suffered by corrosion was carried out through the ASTM G 1 standard, in order to identify and quantify the damage generated by the corrosion in the test, where surface discontinuities produced were detected by corrosion such as: pitting and erosion, which are the possible result of the turbulent flow spray of the saline solution used as a corrosive medium, in addition, that the surface layer of the materials have micropores that help increase the damage suffered by corrosion , since it is a means that allows corrosive fluid to penetrate more easily into the metallic material, generating the types of corrosion mentioned above. As a final result, it was obtained that when comparing the performance of the eight case studies in question, it can be seen that the welded joints of SA-516 grade 70 steel without cathodic protection have a greater weakness against corrosion, while the joints A-36 steel welded without cathodic protection show loss of mass, the latter being the least affected by corrosion. It is very important to perform a previous analysis of the parameters to which the material will be exposed, in order to select in a correct way the sacrificial anode that allows to perform the desired function, to decrease the corrosion rate of the material. A thorough control of the modified parameters in the salt spray chamber must be guaranteed, such as: temperature, flow, pressure and pH (hydrogen pressure), to avoid results alterations of the corrosion test, in addition, it is necessary to use a correct connection between the sacrificial anode and the material that is intended to be protected, better guaranteeing that the oxide-reduction reaction occurs between the metallic materials.