Metodologia para avaliação da corrosão da zona termicamente afetada de aço inoxidável ferrítico AISI 439 soldado

Abstract

Stainless steels are employed in chemical, food and petroleum industries, in which the corrosion resistance of materials is very important. In several of these application it is necessary the utilization of welding operations that affect the mechanical, thermal andmetallurgical properties of the material. The stainless steel corrosion resistance is obtained with the presence of an oxide protect film in its surface. The welding can cause a local composition variation, altering the film stability and the corrosion behavior. In spite of the large utilization of Gas Metal Arc Welding (GMAW) process in stainless steel welding operations there is not much studies about the influence of its parameters on corrosion resistance. The optimization of this process, inserting quality gains and corrosion improvement, becomes important for its better utilization. This work presents a methodology used to set up heat affected zone (HAZ) characterization and determination, through grain size measured by Heyns method. The corrosion resistance was characterized by potentiodynamic electrochemical tests and Pratice W of ASTM A763 standard.