Austenitic stainless steels chromium concentration effect

Fie. 5.26 Effect of chromium concentration on the polarization of chro-° mium modified type 304 austenitic stainless steel. All alloys con-... 

Effect of Thermal History of Austenitic Stainless Steels on Susceptibility to Intergranular Corrosion. The time dependence for the local depletion of chromium sufficient to cause susceptibility to intergranular corrosion as functions of temperature and carbon content is of the form represented in Fig. 7.54 (Ref 83). The curves are typical of type 3xx alloys with nominal chromium concentrations of 17 to 25 wt% and, since they represent times for initiation of intergranular corrosion,... 

Stainless steels are resistant to corrosion by most salts. The exceptions are the halide salts that cause pitting, crevice corrosion, and SCC. Of these salts, those containing chlorides are the most corrosive, followed by fluoride, bromide, and iodide salts. Stainless steels with higher chromium, molybdenum, and nitrogen concentrations will resist pitting and crevice corrosion more effectively. Austenitic stainless steels with higher molybdenum and nickel, ferritic stainless steels with no nickel or copper, and duplex stainless steels will resist SCC. 

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