[en] The susceptibility to stress corrosion cracking of the austenitic stainless steel AISI 304 in MgCl, solution was studied. When changes on the surface film were produced like a prepassivation of the steel in HNO₃ solution or chromate solution or even a previous cathodic reduction. A mixture of MgCl₂ + NaCl was also used in such a way that the cation influence on the scc process could be analised. Results show that the surface film seems to have great importance in the see mechanism and that addition of Na⁺ ions inhibit cracks at the corrosion potencial. (Author)

[en] Hydrogen embrittlement of type 304 austenitic stainless steel was studied by charging thin tensile specimens with hydrogen through cathodic polarization. The elognation decreases with cathodic charging but no longer at the excess of a critical current density. The increase in hydrogen cracking susceptibility by sensitizing is attributted deformation induced martensite and the transport of hydrogen, as cottrell atmosphere on dislocation. The effect of cold working in the case of sensitizing at 800 deg C was that the elongation increases with the degree of cold work. The fracture mode was changed from intergranular to transgranular by cold working and sensitizing. (Author)

[en] The electrochemical behaviour of AISI 304 and 304L stainless steels implanted with N⁺ or Ne⁺ ions in 0.5 and 0.02 M NaCl solutions is compared. The role of dose and implantation current density is studied. Surface analyses of the samples are systematically carried out before and after corrosion tests. The pitting potential of implanted samples is always lower than that of unimplanted ones: the defects generated by the implantation process are probably active sites for pitting. The pit propagation is hindered. The nitrides or α'-martensite layers obtained after elimination of the superficial layers (iron oxide and nickel phase) by electrochemical attack of implanted steel in acidic solution play an important role in this process. (Author)

[en] The main propose of this work, was the determination of the optical conditions for obtaining welded joints of stainless steel, the quality control of joints obtained by destructive and non-destructive essays, as well as, the first specific essays of fluence and fatigue of the base metals employed. All tests performed in the base metals are very important from the joint of view that the comparison between results obtained with base metals and welded joints allows a the evaluation of the efficiency of the welded joints. (author)

[en] The effects of grain sizes and sensitization on the creep behavior of AISI 304 stainless steel was investigated. The study state creep rate of sensitized specimens was always larger than that of non-sensitized ones. The carbides were precipitated on grain boundary during creep and this seemed to have an effect on steady-state creep rate. All of ruptured specimens mainly showed intergranular cracking. (Author)

[en] Corrosion rates of three types of welded 304 stainless steel specimens immersed in 1 N H₂SO₄ solution at room temperature were obtained from potentiodynamic polarization curves, Tafel plots and polarization resistance curves. Corrosion rate measurements by using AC impedance technique were also carried out in order to investigate whether these values agreed fairly well with the values obtained from other electrochemical techniques. Corrosion rates of welded specimens were increased with increasing frequency of GTAW and decreasing current density of GTAW. It was concluded that an A.C. impedance technique could be successfully utilized for determining a local corrosion rate of welded parts. (Author)

[en] The crack propagation behavior of the SUS 304 stainless steel under creep-fatigue conditions was reviewed. Cracks propagated either in purely time-dependent mode or in purely cycle-dependent mode, depending on loading conditions. The time-dependent crack propagation rate was correlated with modified J-integral J^* and the cycle-dependent crack propagation rate was correlated with J-integral range ΔJ_f. Threshold was observed in the cycle-dependent crack propagation, and below this threshold the time-dependent crack propagation appeared. The crack propagation rates were uniquely characterized by taking the effective values of J^* and ΔJ_f, when crack closure was observed. Change in crack propagation mode occurred reversibly and was predicted by the competitive damage model. The threshold disappeared and the cycle-dependent crack propagation continued in a subthreshold region under variable amplitude conditions, where the threshold was interposed between the maximum and minimum ΔJ_f. (orig.)

No abstract available

[en] The criterion is determined for the instability of radial growth of a part-through and part-circumference circumferential crack in a stainless steel pipe that is built-in at both ends and is subject to equal and opposite rotations at the pipe-ends. The instability criterion, obtained by use of the tearing modulus methodology, is expressed in terms of the pipe's geometrical parameters, the crack's configurational parameters and the material's crack growth resistance. The criterion for radial instability is compared with the corresponding criterion for instability of circumferential growth of the through-wall crack that develops as a result of the radial instability. (author)

[en] Abrasive blasting techniques are being developed for canister decontamination. Abrasive blasting with a slurry of frit followed by rinsing with high pressure water is the present reference process. The present reference process was reevaluated, because of equipment design concerns due to the abrasiveness of the slurry, and potential corrosion problems due to possible water intrusion into the canister. The ability of candidate processes to remove radioactive contamination from Type 304L stainless steel specimens has now been quantitatively determined under DWPF conditions. The type of contamination, the amount of contamination, and the heating conditions used spanned the range of conditions expected in the DWPF