Corrosion Assessment of ASME Qualified Welding Procedures for Grade 2101 Lean Duplex Stainless Steel

Abstract

ASME qualified welding procedures do not guarantee suitable corrosion and passivation properties for lean duplex stainless steel welds. An evaluation of two ASME qualified welding procedures to optimize the corrosion performance of tungsten inert gas (TIG) welded grade 2101 duplex stainless steel using ER2209 weld consumable was conducted. The evolution of the microstructure was examined by optical and electron microscopy, ferrite-scope measurements, and scanning Kelvin probe force microscopy. An electrochemical mini-cell was then used to characterize the electrochemical behavior of different weld regions using the techniques such as the double loop electrochemical potentiokinetic reactivation test, standard potentiodynamic polarization tests, and cyclic potentiodynamic polarization. The fusion line was the most critical zone for localized corrosion for both welding procedures, due to the formation of Cr- and Mo-depleted zones, resulting in the highest degree of sensitization. The best performance was attributed to the weld face, due to the presence of higher Cr and Mo contents, highlighting the pitting corrosion resistance. A heat input range of 1.6 kJ/mm to 1.9 kJ/mm and low current density (WPS 1) indicated better corrosion performance of all weld regions. The electrochemical corrosion response was in all cases related to microstructural characteristics of the weld regions. The influence of weld parameters on microstructure development and corrosion performance is discussed.

Corrosion Behaviour of Type 316L Stainless Steel in Hot Caustic Aqueous Environments

“…A NiO peak was determined at 853.6 with a FWHM value of 1.5 eV, with the Ni(OH) 2 peak at 855.4 eV (FWHM 1.8 eV). The obtained nickel peak positions are in good agreement with literature data [38][39][40]. The exact distribution of nickel oxide and hydroxide in the layer was not determined, due to the presence of the satellite peak at 861 eV.…”

On-site weld quality assessment and qualification for stainless steels tanks

“…Each reproved area was double-checked by field metallography performed after electrolytic etching using a 10% (w/v) oxalic acid aqueous solution to attack the microstructure. It was also observed the preferential corrosion attack of Crdepleted regions around Cr-carbides and Cr-nitrides, which promote increased DL-EPR values, corroborating the on-site DL-EPR measurements (Guilherme et al, 2019b). Figure 4 shows photomicrographs from sensitized surfaces obtained by field metallography, where the morphology of the Crdepleted zones was noticed.…”

“…Cyclic potentiodynamic polarization tests were carried out to measure the passivation level integrity in view of ensure the passive film resistance at all over the surface (Guilherme et al, 2019b), and the procedure was performed in 3.5% wt. NaCl solution to evaluate the pitting corrosion resistance.…”

Passivation Level of AISI 316L Aseptic Tank Surface Quantified by On-Site Electrochemical Techniques

“…Electrochemical tests are well established techniques employed in studies of corrosion and passivation of stainless steels [2][3][4][5][6][7] . The use of a micrometric exposed surface area enables more precise evaluation of the electrochemical behavior of stainless steel surfaces [8][9][10][11][12][13] .…”