Search

[ES] El objetivo que se pretenden alcanzar en este proyecto, es el análisis del comportamiento de los aceros inoxidables a nivel corrosivo, en función de distintos estados tensiónales y más concretamente, los relacionados con los esfuerzos de tracción, dentro del ámbito de la soldadura de acero inoxidable. Ha sido empleado para el presente proyecto el Acero Inoxidable AISI 316L, como el material base para la realización de las soldaduras en la probetas (pletinas de acero inoxidable) y utilizando como material de aporte para la soldadura el ER 316L. Donde el proceso de soldadura empleado será el TIG (Tungsten Inert Gas), el cual mantiene la soldadura bajo una atmosfera de gas inerte, que habitualmente es de gas Argón., [EN] They are realized a series of weldings in AISI 316L stainless steel probes with AISI 316L steel rod and tig procedure are made and submit to deformation voltage.

Functionally graded materials (FGM) are a class of materials in which the chemical composition or microstructure varies as a function of position, offering unique material properties. In this study, a functionally graded structure was manufactured using Gas Tungsten Arc Welding and a double wire feed device. The wire feed rate was changed step by step of the austenitic AISI 316L and ferritic AISI 430L stainless steel wire, creating a chemically graded duplex stainless steel structure. The structure, approximately 30 mm in height, was investigated using Optical Microscopy, X-Ray Diffraction, X-Ray Fluorescence and Energy Dispersive X-Ray Spectroscopy. The transverse section is composed of large elongated grains. The chemical analysis revealed a relatively smooth change in Nickel and Molybdenum composition over the section, due to remelting of previously deposited layers. The graded material showed a gradual transition in phase fractions from mainly austenite and some ferrite to mainly ferrite and some austenite, to fully ferric structure. There were no brittle phases detected in the structure.

Spheroidal graphite cast iron is a material widely used in the industry for the manufacturing of all kind of covers and protective casings thanks to its good combination of mechanical properties, processability and cost. When cast iron components are put into service in corrosive environments the most common approach to protect the components is painting them. The protective painting has been found to flake off with time when aggressive washing procedures, such as the ones used in the Food & Beverage industry, are applied several times. In this project, the coating of cast iron with a corrosion resistant AISI 316L stainless steel by Laser Metal Powder Deposition has been studied as an alternative protection against corrosion. Several samples with different combinations of substrate preparation, number of layers and surface conditions were produced and analysed by optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, wash down tests and salt spray chamber corrosion tests. Main results show that the diffusion of carbon from the carbon-rich cast iron to the stainless steel coating, which would have a negative effect on the corrosion resistant properties, was significantly low as a result of the low penetration and dilution achieved during the laser metal powder deposition process. The deposited stainless steel coatings successfully protected the substrate during the corrosion tests and the integrity of the coatings is not expected to fail during the washing producers applied in the industry.

This article investigates the effect of low-level ionizing radiation, namely X-rays, on the micro structural characteristics, resistance, and corrosion resistance of TIG-welded joints of AISI 304 austenitic stainless steel made using AISI 316L filler rods. The welds were made in two different environments: natural atmospheric conditions and a closed chamber filled with inert argon gas. The influence of different doses of radiation on the resistance and corrosion characteristics of the welds is analyzed. Welded material from inert Ar gas chamber TIG showed better characteristics and lesser irradiation damage effects.

(Received: 2015/01/20 - Accepted: 2015/03/25)The continuous improvement of manufacturing processes is critical to achieve optimum levels of productivity, quality and cut production of components and products. This research aims to determine the cutting tool flank wearing progression, during a high speed dry turning, for AISI 316L steel parts. Experimental data were acquired using two cutting feed levels, two material levels, three cutting speeds, and four principal cutting times. A scanning electron microscope (SEM) was used to measure and analyze the wear of the cutting tools. Results were compared using analysis of variance and multiple regression for describing the relation between the variables used in the study. The analysis showed that the three layers coating insert did not exceed the end of life wearing criterion, while the one layer insert suffered a catastrophic wearing at the highest cutting speed. It was found that a relation exists between the experimental data and the predicted values for flank wear with a general average error of 4.1182%., (Recibido: 2015/01/20 - Aceptado: 2015/03/25)La mejora continua de los procesos de fabricación es fundamental para alcanzar niveles óptimos de productividad, calidad y corte en la producción de componentes y productos. Esta investigación tiene como objetivo determinar la progresión del desgaste del flanco de la herramienta de corte durante el torneado en seco de alta velocidad para piezas de acero AISI 316L. Los datos experimentales fueron adquiridos utilizando dos niveles de avance de corte, dos niveles de material, tres de velocidad de corte y cuatro de tiempos principales de corte. Un microscópio electrónico de barrido (SEM) fue utilizado para medir y analizar el desgaste de las herramientas de corte. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión múltiple para describir la relación entre las variables utilizadas en el estudio. En el análisis se demostró que el inserto de tres capas no sobrepasó el criterio de fin de vida del desgaste, mientras que el inserto de una capa sufrió un desgaste elevado para la mayor velocidad de corte. Se encontró que existe una relación entre los datos experimentales y los valores predichos para el desgaste del flanco con un error promedio general de 4,1182 %.

Shear spinning of Haynes 282, Alloy 718, Alloy 600 and AISI 316L was done using several tool feeds and mandrel clearances. Multi passing of the materials was limited due to strain hardening and circumferential cracking except for AISI 316L. The effect of the tool feed and the mandrel clearance on the successful forming of the materials was established. The successfully spun samples were solution heat treated at varying temperatures and holding times to establish a range of grain sizes and hardness levels. An aging heat treatment process was performed for Haynes 282 and Alloy 718 to achieve precipitation strengthening. The micro hardness measurements were conducted for the materials prior to spinning and after spinning. The same was also done after the various heat treatment processes. Grain size mapping was conducted by the use of lineal intercept methods. Comparison of the results in terms of grain sizes and hardness values was done. The temperature ranges suitable for full recrystallization of the materials after the shear spinning were identified and the effect of the holding times on the grain growth established. Comparison with unspun samples showed that the heat treatment times required to achieve comparative hardness and grain sizes were distinctively different.

The corrosion behavior of copper, aluminum and stainless steel AISI 316L in 0.5 mol dm-3 NaCl solution without and with the addition of an aqueous-ethanol extract of green tea leaves at a temperature of 25°C was investigated. Electrochemical parameters where determined by linear polarization measurements and potentiodynamic polarization method, and the surface of the metal samples were investigated using an optical microscope after the polarization measurements. Results have shown that green tea extract acts as a corrosion inhibitor for copper aluminum and stainless steel.

[EN] In this work, the NiCoCrAlYTa Alloy was deposited by laser cladding with different processing parameters (flow rate of powder supplied, feed speed and laser power), in order to analyze the effects of processing on the geometry, microstructure and properties of the coating. We have measured the dimensions of the tracks by optical microscopy and computer image analysis. Scanning electron microscopy (SEM) and energy dispersive spectroscopy microanalysis (EDS) have been used to analyze the microstructure, chemical composition and microhardness variations. The coatings exhibit good geometric aspect ratio without cracks and macro pores, and a good metallurgical bond with the substrate through the dilution zone was obtained; yet there is no a homogeneous columnar dendrite structure that depends on the processing laser. It has been observed that the surface hardness of the coating is twice that of the substrate hardness. The EDS microanalysis evidenced the dilution and mixing of relevant chemical elements such as Fe, Co, Al and Ta with Ni-Cr, generating a gradual variation between substrate and coating which influences the hardening observed at the interface., [ES] En este estudio se ha evaluado recubrimientos de NiCoCrAlYTa depositados sobre AISI 316L mediante la técnica de deposición láser (laser cladding), con diferentes parámetros de proceso (caudal de polvo aportado, velocidad de avance y potencia del láser), con la finalidad de analizar la influencia del procesado sobre la geometría, microestructura y propiedades del recubrimiento. Se ha medido las dimensiones de los recubrimientos mediante microscopía óptica y análisis de imágenes, y se ha estudiado la microestructura, variación de composición química y de microdureza, mediante microscopía electrónica de barrido (MEB) y microanálisis por espectroscopía de energía dispersiva (EDS). Los recubrimientos obtenidos presentan una adecuada relación de aspecto geométrica y no presentan macro defectos importantes, existe una buena unión metalúrgica con el sustrato, con una adecuada área de dilución; no obstante, existe una estructura dendrítica columnar no homogénea que depende del procesado láser. Se ha observado que la dureza en la zona próxima a la superficie del recubrimiento duplica la dureza del sustrato. Los microanálisis por EDS evidencian la disolución y mezcla de elementos químicos relevantes como el Fe, Co, Al y Ta con el Ni-Cr, que generan una variación gradual entre sustrato y recubrimiento que influye en el endurecimiento observado en la intercara del recubrimiento.

Industries that place metal and alloy products on the market are required to demonstrate them being safe for all intended uses, and that any risks to humans, animals or the environment are adequately controlled. This requires reliable and robust in-vitro test procedures. The aim of this study is to compare the release of alloy constituents from stainless steel powders of different grades (focus on AISI 316L) and production routes into synthetic body fluids with the release of the same metals from massive sheet in relation to material and surface characteristics. The comparison is justified by the fact that the difference between massive surfaces and powders from a metal release/dissolution and surface perspective is not clearly elucidated within current legislations. Powders and abraded and aged (24 h) massive sheets were exposed to synthetic solutions of relevance for biological settings and human exposure routes, for periods up to one week. Concentrations of released iron, chromium, nickel, and manganese in solution were measured, and the effect of solution pH, acidity, complexation capacity, and proteins elucidated in relation to surface oxide composition and its properties. Implications for risk assessments based on in-vitro metal release data from alloys are elucidated., QC 20130213

Práce se zabývá zkoumáním svárů z materiálů AISI 316L a TI GR2. Svár je zhotovený rotačním třecím svařováním. První část práce je literární rešerše na téma rotačního svařování třením. V druhé části práce jsou uvedeny výsledky zkoumání svařovaných spojů. Byla zkoumána jejich makrostruktura, mikrostruktura, mikrotvrdost ve všech oblastech svarového spoje, materiály prošly zkouškou chemického složení a svarový spoj byl vystaven tahové zkoušce., The work deals with the examination of welds made of AISI 316L and TI GR2 materials. These welds were formed by rotary friction welding. The first part of the work consists of a literature review and state of the art of rotary friction welding state of the art. The second part of the work presents the results of welded joints examination. The macrostructure, microstructure, microhardness in all areas of the welded joint was examined, the materials passed the test of chemical composition and the welded joint was subjected to a tensile test.

Práce se zabývá zkoumáním svárů z materiálů AISI 316L a TI GR2. Svár je zhotovený rotačním třecím svařováním. První část práce je literární rešerše na téma rotačního svařování třením. V druhé části práce jsou uvedeny výsledky zkoumání svařovaných spojů. Byla zkoumána jejich makrostruktura, mikrostruktura, mikrotvrdost ve všech oblastech svarového spoje, materiály prošly zkouškou chemického složení a svarový spoj byl vystaven tahové zkoušce., The work deals with the examination of welds made of AISI 316L and TI GR2 materials. These welds were formed by rotary friction welding. The first part of the work consists of a literature review and state of the art of rotary friction welding state of the art. The second part of the work presents the results of welded joints examination. The macrostructure, microstructure, microhardness in all areas of the welded joint was examined, the materials passed the test of chemical composition and the welded joint was subjected to a tensile test.

Práce se zabývá zkoumáním svárů z materiálů AISI 316L a TI GR2. Svár je zhotovený rotačním třecím svařováním. První část práce je literární rešerše na téma rotačního svařování třením. V druhé části práce jsou uvedeny výsledky zkoumání svařovaných spojů. Byla zkoumána jejich makrostruktura, mikrostruktura, mikrotvrdost ve všech oblastech svarového spoje, materiály prošly zkouškou chemického složení a svarový spoj byl vystaven tahové zkoušce., The work deals with the examination of welds made of AISI 316L and TI GR2 materials. These welds were formed by rotary friction welding. The first part of the work consists of a literature review and state of the art of rotary friction welding state of the art. The second part of the work presents the results of welded joints examination. The macrostructure, microstructure, microhardness in all areas of the welded joint was examined, the materials passed the test of chemical composition and the welded joint was subjected to a tensile test.

Práce se zabývá zkoumáním svárů z materiálů AISI 316L a TI GR2. Svár je zhotovený rotačním třecím svařováním. První část práce je literární rešerše na téma rotačního svařování třením. V druhé části práce jsou uvedeny výsledky zkoumání svařovaných spojů. Byla zkoumána jejich makrostruktura, mikrostruktura, mikrotvrdost ve všech oblastech svarového spoje, materiály prošly zkouškou chemického složení a svarový spoj byl vystaven tahové zkoušce., The work deals with the examination of welds made of AISI 316L and TI GR2 materials. These welds were formed by rotary friction welding. The first part of the work consists of a literature review and state of the art of rotary friction welding state of the art. The second part of the work presents the results of welded joints examination. The macrostructure, microstructure, microhardness in all areas of the welded joint was examined, the materials passed the test of chemical composition and the welded joint was subjected to a tensile test.

Práce se zabývá zkoumáním svárů z materiálů AISI 316L a TI GR2. Svár je zhotovený rotačním třecím svařováním. První část práce je literární rešerše na téma rotačního svařování třením. V druhé části práce jsou uvedeny výsledky zkoumání svařovaných spojů. Byla zkoumána jejich makrostruktura, mikrostruktura, mikrotvrdost ve všech oblastech svarového spoje, materiály prošly zkouškou chemického složení a svarový spoj byl vystaven tahové zkoušce., The work deals with the examination of welds made of AISI 316L and TI GR2 materials. These welds were formed by rotary friction welding. The first part of the work consists of a literature review and state of the art of rotary friction welding state of the art. The second part of the work presents the results of welded joints examination. The macrostructure, microstructure, microhardness in all areas of the welded joint was examined, the materials passed the test of chemical composition and the welded joint was subjected to a tensile test.

Práce se zabývá zkoumáním svárů z materiálů AISI 316L a TI GR2. Svár je zhotovený rotačním třecím svařováním. První část práce je literární rešerše na téma rotačního svařování třením. V druhé části práce jsou uvedeny výsledky zkoumání svařovaných spojů. Byla zkoumána jejich makrostruktura, mikrostruktura, mikrotvrdost ve všech oblastech svarového spoje, materiály prošly zkouškou chemického složení a svarový spoj byl vystaven tahové zkoušce., The work deals with the examination of welds made of AISI 316L and TI GR2 materials. These welds were formed by rotary friction welding. The first part of the work consists of a literature review and state of the art of rotary friction welding state of the art. The second part of the work presents the results of welded joints examination. The macrostructure, microstructure, microhardness in all areas of the welded joint was examined, the materials passed the test of chemical composition and the welded joint was subjected to a tensile test.