Evaluations of Microstructure and Electrochemical Anodic Polarization of AISI 304L and AISI 316L Stainless Steel Weld Metals with Cr_(eq)/Ni_(eq) Ratio

摘要

This pitting corrosion study of welded joints of austenitic stainless steels (AISI 304L and 316L) has addressed the differentiating solidification mode using three newly introduced filler wires with a flux-cored arc welding process (FCAW). The delta ferrite (δ-ferrite) content in the welded metals increased with an increasing equivalent weight ratio of chromiumickel (Cr_(eq)/Ni_(eq)). Ductility dip cracking (DDC) was observed in the welded metal containing ferrite with none of AISI 304L and 0.1% of AISI 316L. The potentiodynamic anodic polarization results revealed that the Cr_(eq)/Ni_(eq) ratio in a 3.5% NaCl solution didn't much affect the pitting potential (E_(pit)). The AISI 316L welded metals with a-ferrite content of over 10% had a superior E_(pit), value. Though the AISI 316L welded metal with 0.1% ferrite had larger molybdenum contents than AISI 304L specimens, it showed a similar E_(pit) value because the concentration of chloride ions and the corrosion product induced severe damage near the DDC.