Limiting conditions for pitting corrosion of stainless steel EN 1.4404 (316L) in terms of temperature, potential and chloride concentration

Abstract

The main stainless steel grades used for water applications are 1.4307 and 1.4404. The grade selection depends on the conditions: 1.4404 is a more conservative choice and has an improved corrosion resistance over 1.4307. This paper addresses the concept of defining limiting conditions for pitting corrosion of 1.4404 in terms of the environmental parameters such as temperature, potential and chloride concentration. Extensive testing has been done with a combination of short-term electrochemical measurements and long-term chlorination experiments. Results are discussed in the light of the current understanding of the critical levels of key parameters for pitting corrosion.

Complex Corrosion Properties of AISI 316L Steel Prepared by 3D Printing Technology for Possible Implant Applications

“…By entering into the lattice film, the chloride introduces lattice defects, which reduce the resistance of the oxide film to corrosion [62]. Chlorine ions cause local depassivation of spontaneously formed protective oxide layers, and due to the presence of more noble secondary phase particles on exposed surfaces, localized corrosion may occur [63]. The registered values are far under 20 µm/year, which is the maximum corrosion rate commonly accepted for biomaterial design and application [64].…”

Electrochemical corrosion behavior of type 444 stainless steel in synthetic tap water at different temperatures

“…With the reduction of Cl − concentration from 300 mg L −1 , E p shifts positively over the potential of oxygen evolution reaction. As the Cl − concentration reduces to the critical value, the stable pitting corrosion cannot take place (Mameng et al , 2017; Wu et al , 2018). The critical values of Cl − concentration for the pitting corrosion of 444 SS are about 160 mg L −1 , 80 mg L −1 and 60 mg L −1 in the synthetic tap water at 25°C, 55°C and 80°C, respectively.…”

“…the lower the critical Cl − concentration, the worse the pitting resistance. Mameng et al (2017) reported that the critical Cl − content for stable pitting corrosion is temperature independent, e.g. about 35 mg L −1 Cl − at 50°C for 316 L SS.…”

The effect of CeCl3 inhibitor on the localized corrosion of stainless steel in chloride solutions

“…Under certain circumstances, in chloride solutions like seawater, local depassivation takes place bringing about localized corrosion of stainless steels and causing serious accidents. This is especially true for structures with walls, such as pipes and tanks . Welding stainless steel usually increases its susceptibility to localized attacks due to structural transformations and superficial oxidation.…”