The effect of surface treatment AISI 316L welded joints on its corrosion behaviour in chloride solution

Abstract

Investigation of different surface treatment effects on the corrosion resistance of AISI 316L stainless steel welded joints is presented in this paper. The research was conducted using gravimetric tests in 6 wt.% ferric chloride solution as well as polarization measurements in 1 mol dm −3 NaCl solution. Additionally, the mechanism of corrosion attack developed on the steel surface was analyzed by optical microscopy, scanning electron microscopy and energy dispersive X-ray analysis. Before the measurements, the surface of stainless steel welded joints samples was treated by ultrasonic cleaning in ethanol (sample A), ultrasonic cleaning and pickling (sample B), ultrasonic cleaning, pickling and passivation (sample C) and grinding, polishing, ultrasonic cleaning, pickling and passivation (sample D). The results show that the corrosion resistance of 316L SS welded joints increased due to the surface treatment.K e y w o r d s : 316L stainless steel, corrosion, polarization, surface treatment, welding

The Effect of Sensitization on the Susceptibility of AISI 316L Biomaterial to Pitting Corrosion

“…The conditions of the applied chemical surface treatment are presented in Table 3 . The treatment solution was chosen to contain nitric acid (HNO 3 ), which is used as an effective oxidizing agent to strengthen the passive surface film and to raise the redox potential [ 8 , 9 , 32 , 39 ]. Hydrofluoric acid (HF) generates H + ions and it also acts as complexing agent for both Fe 3+ and Cr 3+ ions [ 32 ].…”

“…The treatment solution was chosen to contain nitric acid (HNO 3 ), which is used as an effective oxidizing agent to strengthen the passive surface film and to raise the redox potential [ 8 , 9 , 32 , 39 ]. Hydrofluoric acid (HF) generates H + ions and it also acts as complexing agent for both Fe 3+ and Cr 3+ ions [ 32 ]. The other sensitized specimens were left as the “heat tinted” and used for comparison in potentiodynamic polarization tests.…”

“…Despite the low carbon content, sensitization also occurs with AISI 316L stainless steel and induces a higher susceptibility to the pitting corrosion [ 29 , 30 , 31 , 32 ]. According to the authors of [ 25 , 33 , 34 , 35 ], chromium-depleted zones along the grain boundaries more susceptible to corrosive attack compared to the surrounding matrix become preferential sites for pit initiation.…”

“…Most current studies [ 17 , 30 , 31 , 32 , 33 , 34 , 35 ] evaluate the effect of sensitization on the resistance to the pitting corrosion of AISI 316L steel by electrochemical methods (often by potentiodynamic polarization and EIS) in NaCl solutions (0.01–3.5%). The above-mentioned authors record a significantly higher susceptibility to pitting and degraded quality of the passive surface film.…”

A Study on the Effect of Surface Grinding on Chloride Induced Pitting Initiation of Austenitic Stainless Steel 304 under Thermal Insulation at Ambient Temperature

“…It is suspected that Austenitic Stainless Steel type 304 susceptibility to chloride induced stress corrosion cracking (CISCC) at ambient temperature is dependent on the surface preparation method. Machining and grinding procedures of Austenitic Stainless Steel type 304 increases sensitivity to stress corrosion cracking (SCC) [1].…”