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Crevice growth velocities in samples of AISI L stainless steel thermally welded and sensitized were obtained by the Rising displacement method or of growing displacement. To the end of the rehearsal it was carried out the fractographic analysis of the propagation surfaces. The values of the growth velocities obtained by this methodology went similar to the opposing ones under normal conditions of operation; while the fractographic analysis show the cracks propagation in trans and intergranular ways, evidencing the complexity of the regulator mechanisms of the one IGSCC even under controlled ambient conditions or with mitigation methodologies like the alternative hydrogen chemistry.
Plates of austenitic stainless steel AISI l of 0. They were characterized so much the one base metal, as the welding cord by means of metallographic techniques, scanning electron microscopy, X-ray diffraction, mechanical essays and osotio mechanics.
From the obtained results it highlights the presence of an area affected by the heat of up to 1. Also it was carried out an fractographic analysis of the fracture zone generated by the tenacity essays, what evidence a ductile fracture. The experimental values of resistance and tenacity are important for the study of the structural integrity of the encircling one of the core.
Velocities of crack growth in samples type CT pre cracking of stainless steel AISI l solder and sensitized thermally its were obtained by the Rising Displacement method or of growing displacement. Contrary to the idea of mitigation of the crack propagation velocity by effect of the addition of the hydrogen in the system, the values of the growth velocities obtained by this methodology went similar to the opposing ones under normal operation conditions. To the finish of the rehearsal one carries out the fractographic analysis of the propagation surfaces, which showed cracks growth in trans and intergranular way, evidencing the complexity of the regulator mechanisms of the IGSCC like in mitigation conditions as the alternative Hydrogen Chemistry.
Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel L sensitized and a carbon steel API X65; Estudio comparativo de la corrosion inducida por microorganismos sulfatorreductores, en un acero inoxidable L sensibilizado y un acero al carbono API X In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion MIC in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants.
At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI Lit was not detected damage associated to the inoculated media.
The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn’t seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX From the titanium oxide anatase crystalline phase, the rutile phase was obtained by a heat treatment at degrees Celsius.
The Sigma-Aldrich pre-oxidized powders and steel l were characterized using techniques of X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, chemical mapping and Raman spectrometry.
The surface that contacted the sample holder has larger crystals. Hydrothermal deposits were carry out from suspensions of 10, and ppm, of the crystal phases of anatase, rutile and baddeleyite, on the pre-oxidized steel at a temperature of degrees Celsius for 2 and 7 days, samples were analyzed by X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, Raman spectrometry and Tafel polarization.
The suspension to ppm for 7 days coated surface most; the baddeleyite deposit is noticed more homogeneous than anatase and rutile. The deposit is favored when hematite and magnetite crystals are larger. The chemical mapping on deposits show that even after being immersed in water to degrees Celsius during 30 days, the deposits are still present although a loss is observed. A reference electrode was assembled to conduct electrochemical tests of Tafel able to withstand a temperature of degrees Celsius and pressure of 8 MPa.
The degradation mechanisms in the boiling water reactors BWR have been an alert focus for owners, especially the cracking by stress corrosion cracking SCCtherefore different techniques have been studied to inhibit this problem inside which is the water injection of hydrogen feeding HWC, Hydrogen Water Chemistrytogether with the noble metals injection NMCA, Nobel Metal Chemical Addition and the ceramic materials injection that form an inhibitory protective coating Ipc.
In this work the Ipc was simulated, for which were carried out hydro-thermals deposits starting from suspensions of ppm of zirconium oxide in its crystalline phase baddeleyite and titanium oxides in its anatase and rutile phases, on test tubes of stainless steel l previously rusty under simulated conditions of pressure and temperature of a BWR C and 8 MPa.
The superficial characterization was realized by scanning electron microscopy, energy-dispersive of X-ray and X-ray diffraction.
The capacity to mitigate the corrosion was studied with the electrochemical technique of Tafel polarization C and 8 MPa. The steel presents the formation of two oxide coatings formed by magnetite and hematite. The baddeleyite presents a deposit more thick and homogeneous it also presents the most negative electrochemical potential of corrosion, what indicates that it has the bigger capacity to mitigate the SCC.
Directory of Open Access Journals Sweden. Alloying with copper and bronze improves the density of sintered steels at the two sintering temperatures used.
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Copper and bronze promote liquid phase sintering transitory or permanent, electridas activates sintering process. Tensile strength of stainless steel is highly improved for higher alloying contents. Moreover, tensile strength presents greater values alloying with bronze than with copper. Para el estudio se utilizaron dos tipos de electrodos: Full Text Available The influence of the steelmaking process on the quality and the performance of refractory materials used on stainless steel production was described.
The most important technical and design parameters of the processing units were explained and related with the slag chemical composition and the qualities of the refractories used.
acero inoxidable l: Topics by
Full Text Available From a series of 22 typical 18Cr8Ni stainless steel 40 kg ingots, with copper variable concentrations from 0. Full Text Available In this paper we have studied the resistance to corrosion of the L ferritic stainless steels, manufactured by powder metallurgy. We have compared the behaviour of the different series of L stainless steels sintered, tempered and annealing, in different corrosive environments.
Finally, the microstructure of the steels was determined by means of scanning electron microscopy. El objetivo principal de este trabajo es estudiar el comportamiento termomec Losas de concreto reforzadas con acero inoxidable de desecho Reinforced concrete slabs with stainless steel waste. The results from an experimental program that explores the use of industrial waste materials specifically sheets of stainless steel that result of the currency coinage as reinforcement for concrete slabs are presented.
Twenty three full size beam-deck specimens were built in order to measure resistance, ductility and failure modes; the experimental analysis in models with reinforcement in different quantities shows that in some cases, under certain quantities and location, it is possible to reach similar load capacities and failure modes as specimens with traditional reinforcement.
Based on these results, it is concluded the feasibility of using the material described above as alternative reinforcement in structural concrete elements, as an economic option in the construction of social housing. Full Text Available In this work, the influence of the biofilms in the corrosion process of different alloys of stainless steel was studied in two sampling points in a wastewater treatment plant during 4 years. The physicochemical microenvironment within the biofilms was characterized through O 2H 2 S and pH microelectrodes.
Corrosion rates were quantified from the number, diameter and depth of pits. The results show a remarkable development of the biofilm and a significantly greater number of pits in the grit removal channel than in the sludge recirculation channel.
Based on the characteristics of the water phase and microelectrode measurements, our results suggest that biofilms induced corrosion throughout 3 mechanisms: Full Text Available The welded joints of stainless steels always present problems for the microstructural modifications that occur in the heat affected zone.
Particularly, duplex stainless steels present very important changes when the weld pool solidifies forming fundamentally ferritic structures with some austenite in grain boundaries.
These microstructural modifications, and those which occur in the HAZ, justify the mechanical properties of the joint and mainly those of plasticity, being all of them influenced by the processing conditions. In this work the influence of the laser welding speed on the tensile behaviour of duplex stainless steel welded joints is presented.
The microstructure of the obtained seams and of the heat affected zone will be evaluated by means of optic and scanning electron microscopy.
Also, different microhardness profiles have been obtained to evaluate the modifications in the mechanical properties both in the seam and the zone of thermal affection. Las uniones soldadas de aceros inoxidables siempre presentan problemas por las modificaciones microestructurales que suceden en la zona afectada por el calor. This phenomenon, know as sensitization, it is result from the precipitation of chrome carbides in the grain boundary, making these areas less resistant to corrosion.
Two different electrochemical reactivation tests are compared with a destructive test and related to the classification of its respective microstructures. It was established a quantitative methodology to evaluate the degree of sensitization in AISI and also to compare the correspondence of the results with the data of the automatic and portable EPR device for non-destructive field measurement of the degree of sensitization.
The presence of nitrogen in the sintering atmosphere leads to complex nitrides formation the AISI L sintered steel microstructure. A subsequent heat treatment was applied to modify this microstructure in order to improve the mechanical properties and corrosion resistance of these ferritic stainless steels. Comportamiento al desgaste por deslizamiento en aceros inoxidables: En este proyecto se estudia el comportamiento al desgaste por deslizamiento de cuatro aceros representativos de las cuatro grandes familias de aceros inoxidables: Para cada uno de ellos se han realizado: In this work, ageing thermal treatments at intermediate temperatures in the superferritic stainless steel DIN 1.
After quenching from ageing temperature, twinning formation has been observed, and the extent of twinning is proportional to the increase in hardness, showing in this way that twinning density is proportional to embrittlement level. Por otra parte, se ha detectado la presencia de maclas en el acero envejecido y templado en agua, siendo proporcional su densidad al grado de endurecimiento provocado por el tratamiento. Full Text Available Austenitic stainless steels with molybdenum present high mechanical properties and corrosion resistance to aggressive environments.
These steels have been used to tank and vessel components for high corrosive liquids as phosphoric, nitric and sulphuric acids. These materials with low carbon and nitrogen addition have been proposed candidates as structural materials for the international thermonuclear experimental reactor ITER in-vessel components. Molybdenum addition in austenitic stainless steel improves mechanical and corrosion properties, but with it can produce the presence of nitrogen microstructure modifications by presence or precipitation of second phases.
This paper summarises the fatigue and corrosion fatigue behaviour of two LN stainless steels with different microstructure. Fully austenitic steel microstructure show better fatigue, corrosion fatigue resistance and better ductility than austenitic steel with delta ferrite microstructure, mainly at low stresses.
Full Text Available The microstructure and mechanical behavior at high temperature of a thermomechanical processed duplex stainless steel have been studied. These values suggest that deformation is controlled by a grain boundary sliding mechanism, which causes a decrease in the size of the islands during deformation.
It has been concluded that the mixture of the protective gases employed in the process could have an important influence on the fatigue life of the welded joints of such steel in two different ways. Firstly, through the modification of the radius of curvature at the joint between the welding toe and the base metal and, secondly, through a more pronounced degree of oxidation of the alloying instalacinoes induced by a higher O2 diegp in the mixture.
As far as the metallic transfer mode is concerned, it has been determined that the welded joints obtained under a pulsed arc mode show a greater fatigue life in comparison with the joints ing.beferril under short circuit for both gas mixtures.
Full Text Available An alternative technique for the production of dental restorations with porcelain, is the electrophoretic deposition EPD. In this work, oskrio of dental porcelain doego stainless steel were obtained by EPD using water, ethanol and isopropanol as suspension mediums.
The effect of the porcelain concentration, the intensity of the electric field and the suspension medium on the quantity of deposited mass were studied. All the tests were carried out at constant voltage, using a deposition time of 3 min.
The particle size of the dental porcelain was in the range between 1. The results showed that the porcelain in the aqueous medium presented the major deposition velocity, in comparison with both ethanol and isopropanol. However, due to low the low suspension stability and hydrolysis of the water problems, the best coating finishes were obtained with ethanol. These results were obtained applying voltages between 70 and V, for a deposition time of 3 min. Using isopropanol heterogeneous deposits were obtained due to the low suspension stability and to electrochemical reactions problems in the working electrodes, resulted from the high voltages application.
They become visible by the formation instalacionea biofilms: These biofilms affect not only the durability of the material, but also reduce the heat transfer. The influence of the biofilm growth on the corrosion behavior was studied by electrochemical techniques: The selection of the most suitable material for the exposure conditions is discussed and hypotheses of the corrosion mechanism are presented. Although stainless steel AISI presented the lowest corrosion rate it showed localized deterioration.
Influencia de la soldadura sobre la rotura ppracticas tensiones en tubos de acero inoxidable austenitico del tipo NB TP Full Text Available Corrosion attack in heat exchanger systems is a topic of main interest for the maintenance in each industrial plant.
These are multigalvanic systems with particular geometric and fluidodynamic complexity. Corrosive damages include zinc selective dealeation in copper alloys.