Intergranular corrosion effect

Haynie, F. H. and Ketcham, S. J., Electrochemical Behaviour of A1 Alloys Susceptible to Intergranular Corrosion. Electrode Kinetics of Oxide-covered Al , Corrosion, 19,403t (1963) Ketcham, S. J. and Haynie, F. H., Electrochemical Behaviour of Al Alloys Susceptible to Intergranular Corrosion. Effect of Cooling Rate on Structure and Electrochemical Behaviour in 202A Al Alloy , Corrosion, 19, 242t (1963)... 

Levin, LA. and Maksimova, G. F., Effect of Cold Work on the Tendency Towards Intergranular Corrosion of Type 18-8 Stainless Steel, Khim Mashinosiroenie, 5, 35 (1%1) C.A., 56, 3219... 

Doshi, C. P. and Austin, W. W., Effect of Grain Size on Carbide Precipitation and Intergranular Corrosion in AISI Type 201 Stainless Steel , Corrosion, 21, 332 (1965)... 

France, W. D. and Greene, N. D., Some Effects of Ex(>erimental Procedures on Controlled Potential Corrosion Tests of Sensitised Austenitic Stainless Steel , Corros. Sci., 10,379(1970) Tedmon, C. S. (Jr.), Intergranular Corrosion of Austenitic Stainless Steel , J. Electrochem. Soc., 118, 192(1971)... 

Hodges, R. J., Intergranular Corrosion in High Purity Ferritic Stainless Steel. Effect of Cooling Rate and Alloy Composition , Corrosion, 27, 119 (1971)... 

Gizhermo, R. and Khristo, E., Effect of the Deoxidation Method on the Intercrystalline-corrosion Tendency of Cr-Ni Austenitic Steels , Melalurgiye, 5, 17 (1972) C.A., 80, 98898y Joshi, A. and Stein, D. F., Chemistry of Grain Boundaries and its Relation to Intergranular Corrosion of Austenitic Stainless Steel , Corrosion, 28, 321 (1972)... 

As with most other metal and alloys systems, nickel and certain of its alloys may suffer intergranular corrosion in some circumstances. In practice, intergranular corrosion of nickel alloys is usually confined to the vicinity of welds as a result of the effects produced by the welding operation on the structure of the material in those regions. Alloys that are subjected to other similarly unfavourable thermal treatments may also become susceptible. The compositions of most commercial nickel alloys that are marketed today are. 

Corradi and Gasperini claimed that the potentiostatic method was more effective and simpler than the Strauss test for determining intergranular corrosion of stainless steels, and suggested that the method may lend itself for use on finished equipment in service as a non-destructive test. 

Prevention. In North America, susceptibility to intergranular corrosion and sensitization can be avoided generally by the use of low-carbon grades such as type 316L (0.03% C maximum) in place of sensitization-susceptible type 316 (0.08% C maximum). In Europe, it is more common to use 0.05% C (maximum) steels, which are still reasonably resistant to sensitization, particularly if they contain molybdenum and nitrogen these elements appear to raise the tolerable level of carbon and/or heat input. (Wahid)61, (Krysiak)14 However, this method is not effective for eliminating sensitization that would result from long-term service exposure at 425-815°C. 

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,... 

Fig. 7.55 Effect of carbon content on susceptibility to intergranular corrosion of 1 8 wt% Cr-10 wt% Ni stainless steels in boiling acidified copper sulfate. Open circle, no corrosion solid circle, intergranular corrosion, (a) 0.050% C, 18.22% Cr, 10.95% Ni, 0.049% N. (b) 0.027% C, 18.35% Cr, 10.75% Ni, 0.043% N. Redrawn from Ref 84...

Fig. 7.57 Effect of carbon and nickel content on intergranular corrosion penetration rate of 1 8 wt% Cr-base stainless steels. Alloys sensitized for 100 h at 550 °C. Immersion in boiling 65% nitric acid. Pds., periods (48 h) of exposure. Redrawn from Ref 84...

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