Corrosion behaviour of micro-plasma arc welded stainless steels in H3PO4 under flowing conditions at different temperatures

• Published in: Corrosion science Vol. 53; no. 4; pp. 1237 - 1246
• Main Authors: SANCHEZ-TOVAR, R, MONTANES, M. T, GARCIA-ANTON, J, GUENBOUR, A, BEN-BACHIR, A
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier 01.04.2011
• Subjects: Ammeters; Applied sciences; Austenitic stainless steels; Corrosion; Corrosion environments; Current density; Exact sciences and technology; Heat resistant steels; Joining, thermal cutting: metallurgical aspects; Metals. Metallurgy; Microstructure; Polarization; Potential theory; Stainless steels; Welded joints; Welding; Plasma; Temperature; Plasma arc; Welded joint; Corrosion; Welding; C. Welding; Stainless steel; A. Acid solutions; A. Stainless steel; B. Polarization
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2010.12.017

a-[ordm The microstructure of AISI 316L SS is modified as a consequence of the MPAW process. a-[ordm Better passivation film properties are expected for the non-welded SS. a-[ordm The corrosion rate increases owing to the galvanic effect. a-[ordm Temperature increases galvanic current densities. a-[ordm Temperature provides more noble potential values. This paper studies the general corrosion behaviour of the micro-plasma arc welded AISI 316L stainless steel in phosphoric acid at different temperatures (25-60A degree C) and at a Reynolds number of 1456. Galvanic corrosion has been studied using zero-resistance ammeter (ZRA) measurements and polarization curves (by the mixed potential theory). Results show that the microstructure of the stainless steel is modified due to the micro-plasma arc welding procedure. Coupled current density values obtained from polarization curves increase with temperature. ZRA tests present the highest iG values at 60A degree C; however, the values are very close to zero for all the temperatures studied. This is in agreement with the low value of the compatibility limit and of the parameter which evaluates the importance of the galvanic phenomenon. Both techniques present the most positive potentials at the highest temperature. This study reveals that micro-plasma arc welded AISI 316L stainless steels are appropriated working in the studied H3PO4 media from a corrosion point of view for all the temperatures analysed.