[en] Several testing methods for determining intergranular corrosion properties of type 430 stainless streel are described. These include a new electrochemical potentiokinetic reactivation (EPR) test, a chemical etching test, and modified immersion tests from the ferric sulfate-sulfuric acid and cupric sulfate-sulfuric acid tests. A good agreement was observed between the tests. The tests described in this paper can be utilized for both heat treated and welded samples. (Author)

No abstract available

[en] Decontamination by pickling of steel parts, especially of reactor components, is obtained with a solution containing citric acid 0.1 M to 0.3 M, maleic acid 0.2 M to 0.5 M and hydrofluoric acid 0 to 0.1 M. No intergranular corrosion is observed

No abstract available

[en] Be it nuclear fission or fusion technology, the most severe problems that plague the nuclear fission industry and the breakthrough in the nuclear fusion research and development programs are materials-related problems. Extreme hazardous environments of intense radiation field and high temperature resulted from the fission and fusion reactions demand a careful selection of materials employed in nuclear applications. Materials-related problems do not only occur in the nuclear part of the plant but also in the steam cycle part of the unit similar to fossil fuel plants. Degradation of turbines and corrosion of heat exchanger unit have often stalled the electricity production of power plants leading to significant financial burden on the industry and consumers. The phenomena of intergranular stress corrosion cracking (IGSCC) and irradiation assisted stress corrosion creaking (IASCC) are of particular concern due to its severity and subsequent impacts on nuclear power systems. Despite much of the extensive research to improve materials resistance to IGSCC and IASCC, problems still persist. New materials have been introduced and may help reducing the problems is needed. Recent experiments indicate that intrinsic properties of grain boundaries can affect a wide variety of grain boundary phenomena which in turn affect the bulk properties of polycrystals. The geometrical model of grain boundary structure and potential applications of grain boundary engineering to improve IGSCC and IASCC properties is introduced and discussed

[en] We prove an existence-uniqueness result for the solution of a nonlinear fourth-order differential equation which determines the shape of a grain boundary groove forming by surface diffusion. A variational approximation of the problem leads to an efficient numerical method

[en] Corrosion susceptibility under stress of AISI 304 steel sensitized in a sodium thiocyanate solution has been studied and results were compared with those obtained with solutions of thiosulfate and tetrathionate. Sensitized steel type 304 is highly susceptible to corrosion when under intergranular stress (IGSCC) in thiocyanate solutions but the aggressiveness of this anion is less than that of the other sulphur anions studied (thiosulfate and tetrathionate). This work has been partly carried out in the Chemistry Department. (Author)

[en] The importance of transcrystalline and intercrystalline fatigue cracking in failure analysis is shown. Characteristic differences between intercrystalline corrosion fatigue and intercrystalline stress corrosion cracking are pointed out. Time-dependent stress corrosion crack growth under sustained loads gives rise to strongly frequency-dependent corrosion fatigue crack growth under cyclic loads. Intercrystalline 'true' corrosion fatigue depends on the cyclic stress intensity range and on the environment. Intergranular cracks can definitely be due to fatigue. (orig.)

No abstract available

[en] The behaviour of the Inconel 718 relating to the intergranular corrosion resistance in asreceived condition and in two states of sensitization is studied. The recommendation insert inn the ASTM G-28 and DIN 50.914 has been followed. (E.G.)