Improvement of pitting corrosion resistance of AISI 444 stainless steel to make it a possible substitute for AISI 304L and 316L in hot natural waters

Abstract

The pitting corrosion resistance of AISI 444, 304L and 316L stainless steels in two tap waters with different chloride concentrations at 80 8C was studied. Cyclic potentiodynamic polarization (CPP) tests were carried out starting from E corr À 30 mV until the current density reached 0.1 mA/cm 2 (scan rate 0.166 mV/s); the scan was then reversed and continued until new passivity conditions were achieved. The corrosion potential was measured before the polarization experiments. From the E-log i plots, the values of pitting and protection potential were obtained; from these potentials, the perfect and the imperfect passivity regions were defined to compare the corrosion resistance of the studied steels. CPP tests were performed both on as received stainless steel samples and on samples submitted to different cleaning-passivation treatments to improve their corrosion resistance. The results indicate that, for industrial production, AISI 444 stainless steel can substitute the more expensive AISI 304L or 316L after a cleaning-passivation treatment that reduces the presence of inclusions.

Corrosion behaviour of austenitic and duplex stainless steels in an industrial strongly acidic solution

“…These results indicate that 2707 can be considered the best stainless steel in the strongly acidic solution studied in this work if it will have a mirror like surface finishing (F1), which is, from a practical point of view, quite difficult to achieve in the metallic components of an industrial plant. Therefore, for studying the corrosion performances of stainless steels, it is important to consider their surface finishing, as previously found . Furthermore, the anodic polarisation curves (Fig.…”

The role of titanium in the initiation of localized corrosion of stainless steel 444

“…Similar behavior was documented for samples of SS 444 immersed for a prolonged period of time 20 or immersed in more diluted saline electrolytes. 18,19 The lack of premature pitting before reaching the transpassive region proves the material's low susceptibility to pitting corrosion and highlights the impressive Fig. 5 a 3D model geometry used for the finite element simulations.…”

“…18 Although in many studies the microstructure of the material was characterized using scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (XEDS), little attention was given to the heterogeneous microstructure's effect on localized corrosion. 19,20 In order to investigate the material's polarization behavior on the micro-scale, the micro-droplet cell technique has been performed over Ti-stabilized ferritic SS materials to investigate the relationship between their microstructures and pitting potentials.…”

Effect of antibody solution conditions on filter performance for virus removal filter Planova™ 20N

“…Due to its good mechanical properties at high temperatures and stress corrosion resistance, the AISI 444 ferritic stainless steel (FSS) has been used in many industrial applications such as a coating for equipment in the petroleum refining industry, tubes for heat exchangers in the sugar and alcohol industry, tanks for hot natural water and so forth 1, 2. In many cases, welding is the main manufacturing and maintenance process used to manufacture these components and it may contribute to a particular case of corrosion denominated stress corrosion cracking (SCC).…”