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Atmospheric corrosion is one of the natural phenomena with the greatest impact on the integrity of metallic infrastructures worldwide and especially in tropical environments. However, most atmospheric corrosion studies carried out in natural environments do not exceed 5 years of exposure, and studies with results of 10 or more years are even fewer. This study evaluates the corrosion kinetics of carbon and galvanized steels exposed in the downtown area of Medellín, classified as a moderate aggressiveness environment, from results obtained at 1, 2, 5, 8 and 11 years. For both materials, a corrosion kinetic equation was obtained from Log-Log plots of mass loss, useful for making long-term predictions of the deterioration of structures exposed to the atmosphere. The corrosion of the galvanized was approximately between 10 to 17 times lower than that of carbon steel. [ABSTRACT FROM AUTHOR]

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Failures in welded joints constitute a challenge that requires a scientific approach due to its phenomenological essence. This work determines the causes of failure in welded joints of a piping system, which were carried out with the SMAW process. Visual inspection, tension tests of the base material, chemical analysis by optical emission spectrometry as well as macrograph and metallography of the welded joint were carried out to a sample extracted from the damaged area using a cooled disc. In conclusion, we can say that the cause of failure has its origin in the poor procedure applied when welding, although other factors such as mechanical fatigue or an inappropriate design could also have been present. [ABSTRACT FROM AUTHOR]

A study based in the atmosphere corrosivity evaluation on carbon steel in a coastal zone of the canton of Manta in Manabí, Ecuador, was carried out. Eight exposure sites were selected at different distances from the coastline. Wooden supports with three dry cloth device for the monthly determination of chloride ion salt deposition and six carbon steel metal specimens of standardized dimensions were placed in each exposure site. Three metallic specimens for monthly and annual measurement of atmospheric corrosion rate respectively for each time of exposure during one year of study. Monthly average values of relative humidity, temperature, and wind were obtained from a meteorological station located near the study zone. The results obtained from the typical description of the aggressive coastal environment of the atmosphere, and those demonstrated in terms of the monthly behavior of corrosion rate and the influencing factors, as well as the corrosivity categories of the atmosphere determined at different distances from the coastline, can be taken as criteria for durability, before proceeding with the design, construction, maintenance, and repair of structures in the coastal study zone. A difference between the two variants of corrosivity of the atmosphere evaluation, that it to say, between the estimation from the typical description of the aggressive coastal environment of the atmosphere in the study zone, and the determination using the annual average values of corrosion velocity, was demonstrated. This difference can also be taken as another criterion for durability in the study zone. The extreme (CX) corrosivity category of the atmosphere determined for carbon steel has not been reported in other studies carried out in Ecuador. The chloride ion salt deposition in saline dissolution form continues, to be one of the most influential factors in the corrosion rate or corrosivity of the atmosphere in the carbon steel. [ABSTRACT FROM AUTHOR]

Introduction: In the last decades, the use of the microabrasive rotating sphere test method has been extended in the evaluation of ferrous materials, given its technical-economic advantages, as well as its facilities in the evaluation of hardfacing deposits. Objetive: To develop a free rotating sphere microabrasive testing equipment for the characterization of metallic materials and hardfacing deposits, using design solutions that allow its economic manufacture. Materials and methods: The "Autodesk Inventor Professional 2014" software was used for the design of the equipment, as well as in the modeling of the loads and displacements of the elements of the assembly. Construction steels, carbon steels and an aluminum alloy were used for the fabrication. The parts were manufactured by machining, heat treatment and welding. The adjustment of the equipment was carried out by means of a circularity study of the footprints. Results and Discussion: The developed equipment meets the requirements of the microabrasive wear test. The wear traces obtained on heat-treated GOST X12M steel showed circularity and sharpness of contour, which proves the rigidity of the equipment. This allows its use in the evaluation of metallic materials and hardfacing deposits of high hardness. Conclusions: The developed equipment presents a simple configuration, the mechanical stresses in its components are relatively low, which allows its design with materials of low mechanical resistance. The traces obtained in the adjustment tests show adequate circularity and contour definition, indicating the absence of vibrations that affect the results. [ABSTRACT FROM AUTHOR]

This work aims to study the fracture mechanisms of a low carbon laminated steel under different biaxial stress states employing a universal testing machine with an Arcan type device. The chosen material was an AISI/SAE 1020 steel, A specific butterfly specimen geometry was designed with the aid of finite element simulations to concentrate critical stresses at the center of its neck. The Arcan device can change the specimen's orientation regarding the machine loading axis, generating different biaxial stress states. Tests were carried out on pure tension (0°), combined stress with a predominance of shear stress (60°), and pure shear (90°). An evident deformation was observed in the microvoids generated in the specimens at 60° and 90°, orienting them in the direction of the shear stress, favoring their coalescence, and decreasing their mechanical resistance. Although no apparent difference was observed between the failure surface morphologies of the specimens loaded at 60° and 90°, an evident difference was observed concerning the sample at 0° due to the dominant presence of shear stress. [ABSTRACT FROM AUTHOR]

The present work was evaluated the current electrochemical performance of a commercial corrosion inhibitor by electrochemical methods, used at the top of the atmospheric distillation column. Electrochemical techniques of linear polarization resistance, potentiodynamic polarization curves and electrochemical noise were used to estimate the corrosion resistance of A106 steel and predominant attack type, to the exposure of an acidic corrosive aqueous medium with high contents of chlorides, sulfides and different concentrations of the inhibitor. The results showed that the inhibitor at concentrations greater than 75 ppm exhibited efficiencies greater than 90% with significant drops in corrosion rates and marked increases in resistance to linear polarization. Noise levels decreased markedly with the inhibitor at concentrations greater than 50 ppm, compared to the uninhibited medium. The localization index evidenced the presence of mixed corrosion in the steel exposed to the uninhibited medium, and localized corrosion when the inhibitor concentration was higher than 50 ppm. [ABSTRACT FROM AUTHOR]

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A series of basic concepts established in the atmospheric corrosion specialty regulations (ISO 9223: 2012, ISO 9225: 2012 and ISO 9266: 2012 Standards) are summarized in this work. In this work, a series of basic concepts established in the atmospheric corrosion specialty regulations (ISO 9223: 2012, ISO 9225: 2012 and ISO 9266: 2012 Standards) are summarized. The concepts are taken into account when carrying out a study of atmospheric corrosion or corrosive aggressiveness of the atmosphere for the metallic materials most used in the construction industry (carbon steel, zinc, copper and aluminum). Some experiences obtained that are not included in the regulations of the specialty are described, derived from the latest studies carried out in the tropical coastal climate of Cuba. This indicates the need to execute whenever possible, the first variant for estimating the corrosive aggressiveness of the atmosphere based on the typical description of the atmospheric environment together with the third variant, based on the determination of the direct measurement of the annual corrosion rate in specimens of standardized dimensions. For certain conditions described, there has been a large difference between the estimation, making use of the indirect annual values of corrosion rate determined by the dose / response functions as the second variant and the third variant for determining the corrosive aggressiveness of the atmosphere for the carbon steel and galvanized steel. [ABSTRACT FROM AUTHOR]

Copyright of Opuntia Brava is the property of Universidad de Ciencias Pedagogicas de Las Tunas, Centro de Documentacion e Informacion Pedagogica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The main construction material of oil facilities is carbon steel. The exposition in some media such as atmosphere, waters or others, cause notable affectations due to the corrosion phenomenon. In the investigation, a study of corrosion products that were generated during the atmospheric corrosion process, were carried out in an oil treatment battery. The time interval selected for the study was one year, making evaluations since the first month of exposition. The objectives of this study are to determine physic-chemical properties of phases, by means of solid product characterization techniques, using FTIR (infrared spectroscopy) and XRD (X-ray diffraction) of the corrosion products to obtain the sortometric and porosimetric properties of the solid phases. The lepidocrocite (γ-FeOOH) claim to the orthorhombic crystallographic system, of punctual groups: 2/m²/m²/m and magnetite (Fe3O4) was identified with the isometric system. The crystallines sizes were obtained by the area .of the high intensity DRX peak: 10 Å, 9 Å and 8 Å (γ-FeOOH, α-FeOOH and Fe3O4 respectively). The phase of smaller particle size belonged to the Fe3O4, which showed greater physical-chemical reactivity because it presented the upper surface area (39 m2/g). The iron transformation effects in the three varieties presented positive enthalpies. The disorder component generated changes in the nature phases. The transformation mechanisms responded to:... [ABSTRACT FROM AUTHOR]

Atmospheric corrosion of carbon steel AISI-1018 was studied in a coastal zone of tropical climate of Cuba with the presence of technologies aimed at the oil extraction and refining in operation. Two outdoor exposure sites were placed in the study zone. Wooden racks with device for determination of aggressiveness agent's monthly and averages annual, a sensor for the measurement of relative humidity-temperature complex, as well as fifteen specimens of carbon steel AISI-1018 for determination of corrosion rate monthly and annual, were installed in each exposure site placed at distance from the sea of 70 and 50 m without shielding effect. Corrosivity category of the atmosphere estimated from the typical characterization of the atmospheric environment and from the indirect values of corrosion ratewas similarity to determine from the annual values of corrosion rate determined directly for carbon steel at the two exposure sites in the study zone. Corrosivity categories of the atmosphere determined was high (C4). The atmospheric corrosion of carbon steel is influenced not only by the wet deposition of sulfate ions, but also by the wet deposition of chloride ions at both exposure sites. The relative humidity-temperature complex had a higher influence on the atmospheric corrosion of carbon steel at the exposure site placed at a higher altitude on sea level in the study area. The effect of height on sea level also influenced in a different classification of the types of atmosphere between the two exposure sites. [ABSTRACT FROM AUTHOR]

Biomarkers are complex molecules derived from formerly living organisms such as bacteria, fungi, algae, plankton, lichens, mosses, ferns and other higher plants. Biomarker concentrations are relatively low in oil and due to the high stability of its chemical structures, they are archaeological witnesses to its formation and transformation process. Based on the qualitative and quantitative composition of the molecules, it is possible to know the degree of oil biodegradation, determination of depositional environmental conditions (such as marine, terrestrial, deltaic, or hypersaline environments) and the type of precursor organic matter in the source rock. In addition, it is possible to carry out environmental, forensic and behavioral studies of hydrocarbon reservoirs. The objective of the present work is to develop an analytical methodology to obtain the distribution of saturated terpanes and steranes biomarkers using combined gas chromatography-mass spectrometry. From the extracted ion chromatograms, the peaks of 37 compounds from the group of terpanes and 19 compounds from that of the steranes were identified and integrated. The distribution was determined with their characteristic fragment ions of m/z 191, m/z 217 and m/z 218. Repeatability, intermediate precision and relative standard deviations were lower than 5%, which shows that the results are in agreement with the quality criteria established for analogous chromatographic methods. [ABSTRACT FROM AUTHOR]

Atmospheric corrosion of carbon steel was studied in the oil refinery of Havana, Cuba. Four exposure sites, three in outdoor exposure condition and one in indoor exposure condition were placed in the refinery during one year of study. Corrosivity categories of the atmosphere higher, C5 very high and CX extreme, were expected for atmosphere classified as industrialcoastal, industrial and industrial highly polluted, due to high deposition of sulfate ions. Equivalence between two ways of estimation of corrosivity categories of the atmosphere was demonstrated for the atmospheres classified in the outdoor exposure condition. The high deposition of sulfate ions higher than chlorides, bring as results difference between the category of estimation and determination for atmosphere classified as industrial and industrial highly polluted. The category high (C4) was estimated and medium (C3) was determined. However, for an atmosphere classified as industrial-coastal, where the deposition of chloride ions is higher without being higher than sulphate ions, there was equivalence between the two ways of estimation and determination high (C4) of aggressivity corrosion for outdoor exposure condition. The chloride deposition salts remain as the most influential factor in the atmospheric corrosion of carbon steel, demonstrated in this study, for an atmosphere classified as industrial highly polluted. For the indoor exposure condition, there was equivalence between the estimation and determination of aggressivity corrosion of the atmosphere high (IC4) in the refinery. The increase in RH is the most influential factor in the atmospheric corrosion of carbon steel. [ABSTRACT FROM AUTHOR]

The anticorrosive behaviour of the electrogalvanized carbon steel with PZn, PZn- Ca and PZnNi phosphate layers additionally coated with the conversion layers of cerium oxide in chloride-contaminated media has been studied. The composition and structure of investigated samples were characterized by scanning electron microscope SEM, while the corrosion behaviour was investigated applying voltammetric and electrochemical impedance spectroscopy EIS measurements. The data obtained have shown that all investigated samples additionally coated with cerium oxide conversion coatings exhibited better protective abilities. To summarize the results of electrochemical and SEM measurements it was stated that the most porous (F = ~1-2%) PZnNi/Ce coating exhibited the best protective abilities in a chloride-contaminated solution. Therefore, cerium ions are able to penetrate into the substrate, which is zinc coated steel, through the open pores of the PZnNi layer. [ABSTRACT FROM AUTHOR]

This study proposes by means of analytical characterization techniques, a structural evaluation of the surface modification of a ferrous material by three-dimensional ion implantation plasma technology. Carbon steel substrates immerse in a gaseous atmosphere, were surface-implanted with nitrogen ions via high voltage pulse discharges activated at a low-pressure range ("high vacuum"). The effect of the surface treatment on the structure, composition, and morphology of the substrates was verified by microscopy and spectroscopy techniques. From the micrographs obtained by scanning electronic microscopy and the analysis elemental by energy dispersive spectroscopy the morphology and nitrogen concentration of the treated and non-treated samples were analyzed and compared. As for the elemental analysis by energy dispersive spectroscopy, nitrogen concentration in the implanted substrates were detected and determined at a relatively low amount. In regard to the x-ray diffraction results, a decrease in the intensity of the (110), (200) and (211) planes of the treated substrate compared with the reference substrate, was observed. The analysis of phases-formation on the surface material performed by Raman spectroscopy, identified mainly ferric oxy-hydroxides typical uniform corrosion products. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Currently, the study and measurement of atmospheric aggressiveness is regulated by ISO (International Organization for Standardization) standards. The problem is that the results can be delayed from three months to a year to obtain the required information. This test detects the presence of corrosion in urban-marine and urban-industrial environments in a fast way, which is very important to prevent catastrophic damage to metals such as low carbon steel (AISI-1018), aluminum (Al), cooper (Cu) and galvanized steel (63 µm thickness of Zn). Hence, controlling and preventing corrosion is very important to meet the needs of the automotive industry, metal-mechanical, electricity, building, etc. This paper proposes its use as a rapid method for the evaluation of atmospheric corrosiveness and the efficiency of a temporary inhibitor, simulating marine and industrial atmospheres. In addition, this method can be used as a practice in educational programs. [ABSTRACT FROM AUTHOR]

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The welding of steel of low carbon content is a common practice in the nickel industry, where components with steels of these characteristics are manufactured. The objective of the paper was to establish the microstructural behavior of the AISI 1025 steel when it was welded with two types of electrodes (E 6010 and E 7018), the first one deposited as a mattress, and the second one to guarantee mechanical resistance; they were made in a 240 x 240 x 10 mm plate with simple bevel preparation. The microstructures obtained with the electrode E 6010 are of the ferrite type Widmanstátten, columnar ferrite and intergranular pearlite, with a hardness of 345 HV, while with the electrode E 7018 the microstructures are ferrite Widmanstátten, austenite and martensite, with hardness of 332 HV. The decrease in hardness in the latter case is associated with the thermal treatment of multipass annealing. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The inhibition efficiency of corrosion of the extract of neem leaves (Azadirachta indica) on carbon steel and aluminum was evaluated in contact with a sodium chloride and sodium sulfate solution, both at 3.5% p/v. Corrosion speed was determined and it was found that the Neem extract, at a lower concentration, reached better efficiencies on carbon steel in sodium chloride with 78% efficiency using 5% of the extract; concerning the aluminum, the efficiency values reached were low. Besides, through the adjustment to the Langmuir's isotherms, it was possible to determine that the nem extract was adsorbed spontaneously on the surface of carbon steel and allowed to delay the corrosive process when reaching inhibition efficiencies of 90%. Results of this research allow establishing that the neem extract has a high potential as corrosion inhibitor to be applied in the industry as corrosion preventive medium. [ABSTRACT FROM AUTHOR]

This paper presents the results of evaluating the dynamic corrosion resistance, the erosion and corrosion-erosion, to impact angles of 30° and 90°, with respect to the sample surface in steel ASTM 240 (A240) or AISI 304 and steel ASTM 576 (A576) or AISI 1045. The electrochemical characterization was developed by the Tafel polarization curves and the micro-structural characterization by the scanning electron microscopy. There was a marked decrease in the corrosion rate for steel A 240 compared with A576, under the erosion corrosion and corrosion dynamics conditions. Mechanical wear indicated that the normal angle condition represents higher losses in the material thickness, compared to the grazing angle for the two classes of steels. When comparing the different study materials in normal condition and grazing angle, it is clearly observed that the steel ASTM A576 has the highest loss values volume, in equal exposure time, in comparison with the A240 steel. The scanning electron microscopy application techniques allowed to assess the dominant damage mechanisms and corroborated the results obtained by the electrochemical measurements. [ABSTRACT FROM AUTHOR]

The present work was carried out to evaluate the CO2 corrosion resistance of carbon steels used for tubing in oil and gas industries. Two low alloy steels containing 3% Cr, identified as 3CrA and 3CrB, were studied by electrochemical techniques (Chronopotentiometry, Voltamperometry, Electrochemical Impedance Spectroscopy and Linear Polarisation Resistance) coupled with a rotating disk electrode in order to control the hydrodynamic conditions of the system. Results obtained for 3% Cr steels were compared with those obtained for the conventional carbon steel, obtained from a N80 grade pipe, to evaluate the advantages of these new materials in terms of their CO2 corrosion resistance. Electrochemical tests were performed in a 3.5% NaCl solution previously deaereated and saturated with CO2 at 80 °C up to 72 h of immersion at 1000 rpm. Electrochemical measurements revealed that the corrosion resistance of low Cr steels is higher than that obtained for the carbon steel and decrease in the following order: 3CrB > 3CrA > N80. It is thought that these results might be explained by the differences found in the metallurgical characteristics of the steels (chemical composition and microstructure). In addition, it was found that the CO2 corrosion resistances of the steels increase with the immersion time, regardless of their chemical composition. This behavior was attributed to the formation of a corrosion product layer on the metal surface when the immersion time increases, mainly blocking the metal dissolution reaction. [ABSTRACT FROM AUTHOR]

Ancient metallic artifacts from Battery San Rafael- Bocachica-Colombia, were analyzed for stereoscopic microscopy, Raman, FT-IRMIR and DRX, so as to determine their corrosion degree. In parallel optimization extracting of wax, present in the sugar cane bagasse, one popular agroindustrial waste zone, was the primary step in obtaining an corrosion ecoinhibidor propolis enriched, with molybdenum and zinc phosphate. [ABSTRACT FROM AUTHOR]

The influence of the spraying parameters on the microstructure of ZrO2 -- 36 wt.% Al2O3 y ZrO2 -- 17wt.% CeO2 coatings was evaluated. The coatings were produced by oxyacetylene flame spraying on substrates of AISI 1020 carbon steel, which had a previous deposited bond coat of 90 wt.% Ni -- 5 wt.% Al -- 5 wt.% Mo. The studied variables were the standoff distance between the torch and the substrate (7.5, 10 and 12.5 cm) and the influence of two commercial powders: Eutectic Castolin® and Saint Gobain®. It was established that the internal morphology of the powders has a high influence on the microstructure of the coatings while, the spraying distance has a great influence on the microhardness and the porosity of the obtained zirconia-alumina and zirconia-ceria coatings. [ABSTRACT FROM AUTHOR]

Bacterial corrosion is recognized as a worldwide problem that affects different industries. In oil industries, 40% of the internal damage in transporting pipeline distribution is attributed to microbially-induced corrosion. Several studies have been focused on anaerobic corrosion influenced by sulfate-reducing bacteria and few advances related to the MIC by aerobic microorganisms have been described. In this study, two aerobic bacterial strains isolated from naphtha distribution system of Venezuelan Oil Industries with corrosion damage were tested using Scanning Electron Microscope in order to determine their morphological characteristics and their possible corrosivity on coupons steel surfaces API 5L. Morphological analysis allowed to discriminate that bacterial strains have different morphotypes (cocco and bacilli). The fluorescence microscopy quantification revealed the same sessile cell density values for the both strains. MEB analysis on the metal surface allowed to detect opposed effect produced by the bacterial strains: bacilli type strain generated a protective effect while the cocco type strain did not inhibit corrosion. Instead, in the presence or absence of the cocco type strain, localized corrosion (pitting) like control were obtained, suggesting the prevalence of abiotic corrosion in the condition studied. The results obtained are discussed. [ABSTRACT FROM AUTHOR]

At present work the kinetic study of the corrosion and the oxides formed on carbon steel exposed during three years in a coastal industrial area in three test stations, was carried out. In these areas prevails a strong contamination of sulfur compounds and chloride ions. To achieve the objective layout, the rate of annual corrosion of the steel during the three years of exhibition was determined. They were considered the levels of contamination (chloride ions and sulfate) and used diverse technical such as: diffraction of rays X, infrared spectrometric and analysis thermal differential, with the purpose of studying the mechanisms of phases transformation of the one referred material that they happened as the time of exhibition increases. The categories of corrosive aggressiveness settled down for each one of the test stations, of those which A and B was of very high aggressiveness and C of half aggressiveness. It was proven that the kinetics of the atmospheric corrosion of the steel, obeys the mathematical pattern: C = Atn. With the application of the referred techniques it was possible to characterize the phases of the steel exposed in the stations under study, being these, different types of moisturized iron oxihidroxides : göethite, lepidocrocite and magnetite, and they were established the mechanisms of formation of the products as the time of exhibition increases. [ABSTRACT FROM AUTHOR]

The three-dimensional ion implantation technique (3DII) is an alternative to the material surface treatment which is used to mitigate the corrosion effect in low carbon steels exposed to aggressive media. In this work, the behavior of the surfaces of AISI SAE 1020 steel modified with titanium ions in respect to corrosion is studied by using electrochemical techniques. A considerable decrease in the corrosion rate of the implanted samples compared to the non-implanted samples is demonstrated. Thus an effective mechanism for the steel protection against deteriorations in aggressive media is found. [ABSTRACT FROM AUTHOR]

This work show the first part of a research project towards the development of a corrosion map for Chile. In order to develop this map, the research group considered carbon steel, galvanized carbon steel, copper and aluminum as testing materials. All these materials were exposed to the atmosphere in 31 places along the country. In each one of these corrosion testing sites, the metallic samples were mounted on frameworks. Each framework station had chloride and sulfur dioxide meters as well as a weather station, to measure temperature, environmental humidity, rainfall, wind speed and solar radiation. After six months of exposition, the results show the existence of a correlation between the rate of corrosion, the environmental and meteorological conditions of the area and the mechanical properties of the materials. This information constitutes an important tool of innovation for the industries in Chile, because the obtained information will be helpful to design metallic infrastructure with a longer useful live. [ABSTRACT FROM AUTHOR]

Copyright of Revista Fuentes, El Reventón Energético is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a study carried out to determine the effect of mineral extraneous matter and sugarcane juice on the wear of sugar cane rollers which get in contact with bagasse. A prototype based on the ASTM G-65 standard machine, whose low carbon steel is worn by sliding it against bagasse, was designed and built. Tests with and without juice in the bagasse were carried out. Additionally, the level of mineral extraneous matter was varied. Silica sized between 0.212 and 0.300 mm was used as mineral extraneous matter. Wear was measured in terms of the weight loss shown by the specimens. Scanning electron microscopy was used to analyze worn surfaces. It was found that wear is higher with juice, which causes steel to corrode. This also happens with the presence of mineral extraneous matter. The main wear mechanism observed on the worn surfaces was plastic micro-deformation and micro-cutting due to the silica grains. [ABSTRACT FROM AUTHOR]

This work deals with the experimental study of the effect of the removed metal volume and cutting speed on flank wear of two coating carbide and a cermet inserts during the dry finishing turning of AISI 1045 steel at moderate, medium and high cutting speeds. The results were compared using the volumetric dimension of the cutting tool life, the variance analysis and lineal regression analysis in order to describe the relation-ship between the flank wear and removed volume, obtaining the adjusted model equations. The investigation showed a significant effect of cutting speed and machined metal volume on the flank wear, achieving that the three coating layers insert demonstrated the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speed. [ABSTRACT FROM AUTHOR]

By using Linear Polarization Resistance, Electrochemical Impedance Spectroscopy and Tafel Extrapolation, the corrosion resistance of a carbon steel API 5L X65 degree was evaluated in the Rotating Cylinder Electrode (RCE), submerged in a 3%p NaCl solution deareated and 40 ºC at atmospheric pressure. The dynamics of tests was controlled by the RCE with speeds between 0 and 3 m/s, and varying the H2S/CO2 molar relation from 0 to 8.34x10-3. The mass transference coefficients of H+, HS- and HCO3- and the shear stress near the interface metal-liquid interface were determined, by using applicable experimental correlations for the geometry of RCE. Finally, correlations were determined which showed the relationship between the corrosion rate and the mass transference coefficients and shear stress, with the fluid flow of this multiphase system and the H2S/CO2 molar ratio. [ABSTRACT FROM AUTHOR]

In this study the pitting corrosion of steel API 5L grade B in saline solution and saturated with CO2 was evaluated, which are part of the fluids involved in oil production, the technique used for the study of this phenomenon was electrochemical noise (EN), to observe the possible effects on the electrode surface; The tests were performed at 25 and 45°C, varying the Cl-ions concentration between 500 and 24000 ppm. With the electrochemical noise test was detected the onset of pitting process. Tests were conducted at 2, 4, 6, 48, 480 hours, to ensure a reliable analysis of the phenomenon. Was concluded that the synergistic behavior between chlorides ions and CO2 content on carbon steel API 5L grade B immersed in saline solution, at different concentrations and saturated by bubbling with CO2, affects the microstructure of the material. [ABSTRACT FROM AUTHOR]

The scanning electron microscopy (SEM) is commonly used in the areas of corrosion and materials for corrosion failure analysis and materials characterization. In the specific case of microbiologically induced corrosion (MIC) by the action of sulfate-reducing bacteria (SRB), is used quite regularly to characterize biofilms formed on different metal substrates and to identify the morphology of the microorganisms causing the problem; however, very little has been reported correlating the open circuit potential of the metal, sessile bacterial growth of bacteria, biofilm morphology and attack analyzed by SEM and the corrosion products analyzed by SEM-EDX and XRD. That is why in this research, experimental design was structured to allow for these correlations, using a cell electrochemical hydrogen permeation, inoculated in the load cell with the bacterial strain Desulfovibrio desulfuricans subspecies desulfuricans ATCC 7775, for tracking the oxidation-reduction reactions, while the discharge cell was maintained with 0.1 N NaOH to oxidize hydrogen atoms permeated from the load cell with an applied current of 200 mV, which made possible the monitoring of the cathodic reaction of hydrogen reduction by permeation current. The correlation allowed establishing a mechanism of action of these bacteria on carbon steel in media loaded with ferrous ions. [ABSTRACT FROM AUTHOR]

The steels used for tinplate are microalloyed steels with low carbon content. Some of the applications for which tinplates are potentially considered are the manufacture of different types of containers for the food industries and ornaments. Due to the increasing cost of alloying elements, the search for processes to obtain different properties even in the same alloy is relevant. The study of the microstructural and mechanical properties enables a more effective control of the manufacturing process of the final rolled product. The objective of this work is to investigate the influence of temperature, chemical composition and microstructure on the mechanical properties of a cold rolled low carbon steel. It is of particular interest of this research to analyze the drawbacks resulting from incomplete recrystallization. [ABSTRACT FROM AUTHOR]

This paper presents a study of the thermomechanical properties of low carbon steel, AISI-SAE 304 stainless steel, aramid and carbon fibers. Moreover, surface aspect of mineral rock wool of and aluminosilicate wool reinforcements was analyzed prior and after submitting to heat treatments at 1000 ºC. The tensile resistance of the fibers was evaluated prior and after submitting to heat treatments at temperatures of 400, 600, 800 and 1000 °C depending on the degradation that they showed. Moreover, a thermogravimetric analysis was carried out on each kind of fiber to determine the changes in weight at different temperatures. The stainless steel fibers showed the highest mechanical stability, whereas the aramid fibers with treatments at 400 °C showed practically null mechanical properties. [ABSTRACT FROM AUTHOR]

In the production and transportation of oil and gas there are many common problems of erosion-corrosion. The velocity of the flow and the drag of solid particles within the oil transported by pipelines are critical factors in the process of deterioration of low-carbon steels in the presence of CO2. In this research, tests of erosioncorrosion were performed in a cell with a dynamic system of rotating cylinder electrodes at speeds between 1 and 3 m / s, particle sizes between 300μm and 50μm at concentrations between 1 and 9% by weight. Techniques of direct current and alternating current were used to determine the corrosion rate under the conditions evaluated and determine the influence of the particles of sand and the speed of rotation on the corrosion rate of steel. A mathematical relation between the corrosion and system variables was calculated. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and numerical analysis for the description of the mechanical behaviour of a carbon steel wire during an industrial process of damp drawing. Firstly, an experimental procedure aimed at measuring wire drawing forces in the twelve reductions present in the process was performed. Secondly, tensile tests were carried out in order to characterize the mechanical behavior of the material for each reduction step. The resulting stress-strain curves together with the computed responses obtained from the simulation of such tests allowed to derive the evolution of the representative elastic and plastic material parameters. This parameter evolution clearly refiected the relevant amount of hardening experienced by the material which, in turn, imposes restrictions over the drawing operation. The numerical simulations were conducted via a large strain elasto-plasticity model implemented in an existing finite element-based code called VULCAN. The material parameters obtained in the tensile tests were considered as data for the modeling of the entire wire drawing sequences. The computed results are considered as reasonable and representative of the material response during the deforming process. [ABSTRACT FROM AUTHOR]

In this work, the results obtained until the moment in the process of the Analysis and Synthesis of an automated system for the dosage of carbon steel heats in electric arc furnaces exposed. The Internal Analysis process carried out includes the experimentation in industrial conditions and the elaboration of the mathematical model of the kinetics of manganese assimilation by the metal. Although until the moment the developed system doesn't include the optimization algorithm, from the analysis carried out it is not difficult to elaborate the required procedure. [ABSTRACT FROM AUTHOR]

In this work adherent (AR) and non-adherent (NAR) rust, formed on low carbon steel coupons exposed to total immersion corrosion processes in a 0.6 M NaCl solution, were obtained. The immersion was realized for 7 days. The Mössbauer spectra (MS) of the AR show the presence of lepidocrocite (γ-FeOOH), goethite (α-FeOOH) and/or akaganeite (β-FeOOH) phases plus a spinel phase. On the other hand the γ-FeOOH/β-FeOOH and the possibly superparamagnetic goethite phases were more abundant in the NAR samples. The Scanner Electronic Microscopy (SEM) images show clusters formation in both AR and NAR with mean particle size of 1.6 and 4.4 µm, respectively. The chemical composition measurement obtained by energy dispersive X ray shows 71.49 y 77.87% on weight of iron in AR and NAR, respectively. In addition, vibrational bands asociatted to the different phases which were found by MS, were identified using diffuse refectance infrared Fourier transform (DRIFT). [ABSTRACT FROM AUTHOR]

The present work is an answer to the necessity of determining the effectivity of three corrosion inhibitors, such as Corromin E2, mosto or vinaza and Casuarina e liquid extracts in alkaline, neuter and acid mediums, with the purpose of being used for the different systems at these conditions of pH (3, 6 y 9) at environment temperature. It is analyzed the velocity of corrosion of the metallic materials, carbon steel (CT3KP), stainless steel (12X18H10T) and copper (Cu:99.98 %, Zn: 0.01 %, Ni: 0.005 %. Pb: 0.005 %); such as the efficiencies of the inhibitors under the conditions of work previously mentioned. The method used was the potentiostatic. They are presented graphics where can be observed the behaviors of the materials and tendencies of the inhibitors, such as tables that show the results obtained during the investigation . Finally, it is concluded which is the best inhibitor for each one of the different mediums and materials analyzed. [ABSTRACT FROM AUTHOR]

Today inhibitors is one of the most used methods to diminish the corrosion rates, little proportions of added substances into the corrosive environment are effective. The main objective of this work is knowing the electrochemical behaviour in different concentrations (0, 0.06, 0.08 and 0.1 % volume) of a tannin-base inhibitor, synthesize on lab scale, on carbon steel CT3-KP, into different pH values (3, 6 and 9). It's well known that tannin extracts have properties that inhibit corrosion. inhibitor have not only tannin but also other active components, such as amino acids, reduction phenols and saponins, all these substances give to the inhibitor a synergic effect. The electrochemical method of evaluation we selected was the potenciostatic, it's based on creating a steady potential between two electrodes: one on the charge of measurements and the other one a reference electrode, so we get the values of variation of electric current and some aspects from the behaviour of the studied object. We jumped into interesting conclusions: with the pH-3 the inhibitor was cathodic, moving the corrosion potential into more negative values and helping the cathodic branch, however, it doesn't happen with the anodic branch where the inhibitor doesn't act in the positive way, it's self evident when negative efficiencies are obtained, meaning that process has been accelerated. With pH values from 6 to 9, the inhibitor had an universal behaviour, and it was mainly related to the cathodic branch. [ABSTRACT FROM AUTHOR]

This article presents the results of an investigation whose fundamental objective is to do a corrosion study at the atmospherical distillation tower and its overhead system at the Hermanos Díaz Refinery evaluating the corrosion inhibitors Corromin E2 and Chemadd H810F like protector methods to reduce the corrosion rate in this system. Actually, they refined a mixture of national crude and importation crudes. It was used the loss weigh method for corrosion rates calculations, and the experiments were done at the industry. In the experiments with the two inhibitors, were studied the metallic materials: carbon steel and chromium steel 08X13 and was comprobated that Corromin E2 was not a good inhibitor for not one of the materials studied. The Chemadd H810F inhibitor was not adecuated for carbon steel, but it was a satisfactory inhibitor for chromium steel with efficiencies greater than 90 %. With Chemadd H810F inhibitor at industrial scale, were studied too the metalic materials: monel, stainless steel 12X18H10M2 and Al Brass, and it was comprobated that the two first materials do not need inhibitors because their corrosion rates were the lowest and they are maintained in the stability range. For Al Brass, Chemadd H810F was not a good inhibitor. [ABSTRACT FROM AUTHOR]

The traditional methods of steel production use the ferromanganese to obtain the percentage of Mn in the established mark according to the Cuban norm, but this compound is highly expensive. In the production of the Ac 35, it was substituted the ferromanganese by pirolusite (MnO2) with the purpose of reducing the costs. It were evaluated two substitution variants; the first one consists on adding the mineral with aluminum chips and coke (or residuals of electrodes) on the scum of the metal during the reduction process; the second one uses the manganese mineral instead of that of iron during the process of oxidation of the sludges. It was found that both variants are feasible and that the second also turn out to be more economic. [ABSTRACT FROM AUTHOR]

This work contains a study about the behaviour of carbon steel, cast iron and common brass in sea water, and in it were determined the positions of these metals in the corrosion resistance scale in sea water alone, and using two protection methods, such as the addition of an inhibitor obtained from the Casuarina e. leaves and the presence of a magnetic field with different magnetic induction values. The experiments were made at three values of temperature and three magnetic induction values, and it was demonstrated that the inhibitor accelerates the corrosion rate but the magnetic field exerts a favourable effect for the three metals at different magnetic induction values, decreasing the corrosion rate. The sinergetic effect was only exhibited in the carbon steel at the three magnetic induction values. [ABSTRACT FROM AUTHOR]

In this work it has been determined the influence of the magnetic treatment upon the behavior of the galvanic couple copper-carbon steel in aqueous solutions of sodium hydroxide and hydrochloric acid solutions and its influence on the corrosion rate. It was demonstrated that the magnetic treatment of working solutions exerts a positive effect in decreasing the corrosion rate, and this protection method was better than the use of mosto (waste residual of ethylic alcohol production) as inhibitor. Better results have been obtained by using the combination of magnetic field and the inhibitor (sinergetic effect). It was also obtained the mathematical model which relates the corrosion rate with pHs values and magnetic induction at the working temperature. [ABSTRACT FROM AUTHOR]

The present work proposes the study of soapy solutions and Diesel-water emulsions as cooling fluids in cutting tool machines at temperatures 32, 40 and 50 ºC. They have been determined the properties which characterize these fluids and they have been compared with those established by registered firm Castrol for its cooling liquids. The gravimetric method has been employed for measuring the corrosion rates of metallic materials such as carbon steel, cast iron, technical aluminium and brass in the media that have been tested. They have been used sodium triphosphate and Casuarine e. liquid extracts as corrosion inhibitors. The best inhibitor used in the soapy solutions was the mixture of sodium triphosphate and Casuarine e. extract; in the case of emulsions the one used was the Casuarine e. extract at a concentration 10 mL/L; concentrations higher than this caused inestability in the emulsions. The soapy solutions turned out to be effective in almost all the materials, except for the aluminium in some of them; regarding to the emulsions they were effective and stable, being the best those that used Tween R 80 as emulgent. [ABSTRACT FROM AUTHOR]