Effect of Temperature and Impurities on the AISI 316L/Microplasma arc welded AISI 316L Galvanic Pair in H3PO4 under Flowing Conditions

This work studies the influence of temperature (25, 40 and 60 °C) on the corrosion behavior of base and welded AISI 316L stainless steels in phosphoric acid polluted by sulfuric acid and chloride ions under hydrodynamic conditions (Reynolds number = 1456). Galvanic corrosion is studied by means of the mixed potential theory. The effects of impurities on corrosion and galvanic corrosion rates are considered. Results show that, in polluted acid, the heat treatment due to the welding technique affects on the AISI 316L stainless steel increasing the corrosion current densities. On the other hand, temperature and impurities increase corrosion and galvanic corrosion rates. The galvanic effect of the base/welded pair in polluted phosphoric acid was neither significant nor severe