[en] Rotating bending fatigue tests were performed on the commercial medium carbon steel(S45C) coated with two kinds of only aluminium and aluminium-beryllium. A decrease of the fatigue strength was observed and increased according as the thickness of a alloy layer increased. But the addition of beryllium to molten aluminium bath decreased the hardness of alloy layer and improved the more fatigue strength than pure aluminium coating. (Author)

[en] In this thesis the material behaviour of Ck 15 under strain and stress control is presented. A new bounding surface model is developed. The hardening and softening behaviour is described in the experimental part by cyclic loading with strain limits. Ratchetting is the result of uniaxial cyclic tests under stress control. Small differences between loading and reloading path sum up to a cyclic creep strain. This behaviour is observed in nonproportional processes, too. To prevent overprediction of the cyclic creep, a transient bounding surface in stress space with constant radius is introduced. The evolution of the bounding surface is divided into an oscillating part and a recovery part. That way shakedown as well as ratchetting can be modeled. Material functions are determinated phenomenologically. Numerical simulation shows good results compared with the experimental data in a wide range of application. (orig.)

No abstract available

[en] The thrust of this work was to investigate published J material resistance and stress-strain data applicable to the understanding of crack propagation in tough ductile steels, particularly SA 106 Grade B pipe steel. This data has been assembled from PIFRAC, AECB report INFO-0254-1 and Ontario Hydro sources and has been uniformly formatted and presented to facilitate comparison and assessment. While the data is in many aspects incomplete it has enabled an evaluation of the influence of temperature, specimen thickness and specimen orientation to be made in the context of the experimental J-R curves so determined. Comparisons of the stress-strain data within the Ramburg-Osgood formulation are also considered. A further component of this report addresses the development of the required software to utilize what is referred to as the engineering approach to elasto-plastic analysis to investigate the load carrying capacity of selected cracked pipe geometries which are representative of applied crack propagation studies associated with piping systems in the nuclear industry. Three specific geometries and loading situations, identified as Condition A, B and C have been evaluated; the results are presented and illustrate the variation in applied load as a function of an initial and final crack extension leading to instability

[en] Stabilization time is an important parameter in long-term prediction of carbon steel corrosion in atmosphere. The range of the stabilization time of carbon steel in atmospheric corrosion has been published in many scientific literatures. However, the results may not precise because engineering experiences is dominant. This paper deals with the recalculation of stabilization time based on ISO CORRAG program, and analyzes the results and makes a comparison to the data mentioned above. In addition, a new thinking to obtain stabilization time will be proposed. (paper)

[en] Sulphate-reducing bacteria (SRB) are the most important organisms in microbiologically induced corrosion. In this context, the paper presents an assessment (by experimental tests) of the behaviour of carbon steel samples (SA106gr.B) in SRB media. Some of samples were immersed in microbial environment in order microbiological analysis of their surface and another part was used to perform accelerated electrochemical tests to determine electrochemical parameters for the system carbon steel / microbial medium (corrosion rate, the polarization resistance of the surface, susceptibility to pitting corrosion). The surfaces of the tested samples were analyzed using the optical and electronic microscope, and emphasized the role of bacteria in the development of biofilms under which appeared characteristics of corrosion attack. The correlation of all results confirmed that SRB accelerated the localized corrosion of the surfaces of SA 106gr.B carbon steel. (authors)

[en] This specification prescribes requirements for carbon steel covered electrodes for shielded metal arc welding of carbon and low alloy steels. These electrodes are the most widely used in the welding industry

[en] Hydrogen diffusivity through steels at room temperature has been known to deviate considerably from the expected Arrhenius relation. This deviation is due to the attractive interactions between dissolved hydrogen and trapping sites (imperfections in the steel lattice). In a previous work it was shown that the apparent diffusion coefficients attain a minimum value in a fresh martensite and diffusivity increases in the same material tempered at 453 k during six hours. In order to explain this difference, the variation of hydrogen trapping sites with the tempering time, at the mentioned temperature, was studied by means of hydrogen permeation tests. Carbides precipitation was followed by means of the extraction replica technique using transmission electron microscopy. The hydrogen diffusivity obtained by the hydrogen permeation tests attained a minimum value in the quenched specimens and increased with increasing tempering time up to reach a constant value between three and six hours. This change in the hydrogen diffusivity was attributed to the trapping sites decrease promoted by carbides precipitation and their precipitation kinetics was described by an Avrami equation. (author). 4 refs., 4 figs

[en] With respect to structural carbon steel(SM 22C), it was studied how the overstress or the understress has effects on fatigue inside crack propagation curve of a two level stress. Obtained results are summarized as follows. 1) The overstress or the understress, at a slip band occurrence stage, does not change the inside crack propagation curve because the crack closure and opening phenomena do not happen. 2) The overstress, at a crack propagation stage, does not change the inside crack propagation curve because the crack closure of overstress in compressive state is nearly same that of base stress in compressive state. 3) The understress, at a crack propagation state, give rise to an acceleration of crack growth because the crack closure of understress in compressive state is more open than that of base stress in compressive state and the phenomenon is the essential increase of the actual applied stress of the specimen. (Author)

[en] The corrosion behavior of carbon steel in 3 and 5 mol/L aqueous solutions of lithium hydroxide at 95 degrees C under a hydrogen atmosphere was investigated in immersion tests lasting ten days. Corrosion rates were determined by wight loss, and the corrosion products were characterized by bulk chemical analysis, by light and electron microscopy, and by powder X-ray diffraction. Corrosion was uniform and the corrosion rates were moderately high (0.42 mm/y in 3 mol/L and 0.56 mm/y in 5 mol/L). The corrosion products consisted of a mixture of well-formed, octahedral crystals, and poorly crystallized masses and spherules that formed by precipitation from solution. These products formed a scale on the metal surface that continually sloughed off and afforded only minor protection. Both phases were identified as lithium-iron oxides, each possessing a disordered, non-stoichiometric structure. The predominant phase was a magnetic spinel LiFe₅0₈ and the minor phase was LiFe0₂. A corrosion mechanism is outlined. (2 figs., 5 tabs., 20 refs.)