The mechanism of pitting initiation and propagation at deformation bands intersection of cold-rolled metastable stainless steel in acidic ferric chloride solution

Pitting Performance of Cold- and Hot-Rolled Nickel-Saving High-Strength Metastable Austenitic Stainless Steel

“…In order to investigate the pitting mechanism of the experimental MASS, the CRand HR-MASS samples were separately subjected to immersion tests via acidic ferric chloride solution for different time in ambient temperature (~25 • C). The samples used for the immersion tests were prepared by the same grinding and polishing procedure as mentioned in Section 2.2, and the acidic ferric chloride solution was prepared by mixing 6 wt.% FeCl 3 and 0.05 M HCl with 900 mL deionized water as the solvent [34]. Then, the samples were immersed into the corrosive solution for a cumulative time of 3 min.…”

“…Mudali et al, studied the pitting corrosion resistance of a nitrogen alloyed 316 L SS after cold working, pointed out that the cold work reduction beyond 20% is detrimental to the pitting resistance of the steel, and the Cr-depleted zone caused by shearing of Cr-N rich clusters in deformation bands could become the active site for pits initiation [33]. Zhang et al, also had proposed that the "dislocation etch-pits" on a cold-rolled 14Cr10Mn MASS surface were initiated at the deformation bands intersection and related to the crystallographic plane orientations [34]. The vacancy bands and groups formed by edge dislocation slipping and partial dislocation outcrops dissolving, respectively, should trigger the regular-shaped "dislocation etch pits".…”