13 documents found, page 1 of 2
Deformation Induced Martensite in an AISI 301LN Stainless Steel: Characterizati...
Abreu, Hamilton Ferreira Gomes de; Carvalho, Sheyla Santana de; Lima Neto, Pedro de; Santos, Ricardo Pires dos; Freire, Válder NogueiraIn austenitic stainless steels, plastic deformation can induce martensite formation. The induced martensite is related to the austenite (γ) instability at temperatures close or below room temperature. The metastability of austenite stainless steels increases with the decreasing of stacking fault energy (SFE). In this work, the deformation induced martensite was analyzed by X ray diffraction, electron back scatt...
Sensitization evaluation of the austenitic stainless steel AISI 304L, 316L, 321...
Lima, Adriano Sampaio; Nascimento, Alex Maia do; Abreu, Hamilton Ferreira Gomes de; Lima Neto, Pedro deThis work presents a systematic investigation of the influence of time and temperature in the sensitization of stainless steel AISI 304L, AISI 316L, AISI 321 and AISI 347 pipes used in petroleum refining plants. The sensitization was assessed by Scanning Electron Microscopy (SEM) according to ASTM A-262 and by the Double Loop Electrochemical Potentiokinetic Reactivation test (DLEPR). The results showed that all...
Determination of the sensitized zone extension in welded AISI 304 stainless ste...
Lima Neto, Pedro de; Farias, Jesualdo Pereira; Herculano, Luís Flávio Gaspar; Miranda, Hélio Cordeiro de; Araújo, Walney Silva; Jorcin, Jean-BaptisteExtension of sensitized zone (SZ) in welded AISI 304 stainless steel was determined by two non-destructive electrochemical tests: double loop electrochemical potentiokinetic reactivation technique (DLEPR) and local electrochemical impedance spectroscopy (LEIS). Welding was carried out using the shielded metal arc with two selected welding energies: the first one (0.7kJmm¡1) does not promote the sensitization of...
Corrosion behavior of austenitic stainless steels in CO2-saturated synthetic oi...
Cardoso, Jorge Luiz; Mandel, Marcel; Krüger, Lutz; Herculano, Luís Flávio Gaspar; Lima Neto, Pedro de; Silva, Marcelo José Gomes daThe corrosion behavior of austenitic and superaustenitic stainless steels was investigated in carbon dioxide-saturated synthetic oil field formation water using cyclic polarization tests. In order to measure the effect of carbon dioxide pressure, the samples were also exposed in a pressurized medium containing carbon dioxide and synthetic air. For this purpose, tests were performed for long exposure time at 80 ...
Avaliação e comparação da resistência à corrosão por pites do aço super austení...
Silva, Marcelo José Gomes da; Cardoso, Jorge Luiz; Cavalcante, Alfredo Leão Silva Nunes; Lima Neto, Pedro de; Abreu, Hamilton Ferreira Gomes deThe pitting corrosion resistance of a super austenitic AL-6XN PLUS™ stainless steel (ASA) and of an austenitic 317L stainless steel was investigated using the cyclic polarization technique following the standard ASTM G61-86. These materials were evaluated in the as received condition and heat treated ranging from 500ºC and 900ºC during 72 h. Super austenitic steels are derived from austenitic 317L steel, theref...
Influência da temperatura na resistência à corrosão por CO2 DO aço 904L
Dias, Diego Henrique Fonteles; Cardoso, Jorge Luiz; Lima Neto, Pedro de; Silva, Marcelo José Gomes daThe resistance to corrosion by CO2 of 904L superaustenitic steel was investigated using the technique of linear polarization. Heat treatments were performed on samples of 904L steel to simulate the effect of temperature on the resistance to corrosion by CO2. The temperature selected to heat treatments was 760ºC. Samples in the as received condition were also evaluated. The samples were immersed in artificial wa...
Avaliação e comparação da resistência à corrosão por pites dos aços 304L E 316L
Cardoso, Jorge Luiz; Cavalcante, Alfredo Leão Silva Nunes; Belo, Jardel de Souza; Lima Neto, Pedro de; Silva, Marcelo José Gomes daA resistência à corrosão por pites dos aços inoxidáveis austeníticos AISI 304L e 316L foi investigada utilizando a técnica de polarização cíclica seguindo a norma ASTM G61-86. Foi realizada uma simulação termodinâmica utilizando o software Thermo-Calc para prever possíveis fases deletérias nas temperaturas selecionadas. As simulações previam a fase sigma na faixa de temperatura selecionada. Estes materiais fora...
Resistência à corrosão dos aços inoxidáveis austenítico e super austenítico em ...
Sousa, João Matheus Batista Amaro de; Cardoso, Jorge Luiz; Lima Neto, Pedro de; Silva, Marcelo José Gomes daThe pre-salt region is very hostile to the materials used in such environment due to some factors found under the pre-salt layer such as: corrosive gases, oil formation water, high pressures and so on. In order to evaluate only the effect of the oil field formation water on the corrosion resistance of austenitic stainless steels in such environment, two austenitic and two superaustenitic stainless steels were t...
An ab initio explanation of the activation and antagonism strength of an AMPA-s...
Martins, Ana Caroline Vieira; Lima Neto, Pedro de; Barroso Neto, Ito Liberato; Cavada, Benildo Sousa; Freire, Valder NogueiraWe report quantum biochemistry calculations focusing on the binding pocket of the glutamate receptor co-crystallized with agonists (full and partial) and a antagonist. The calculated electronic binding energy follows the order AMPA . glutamate. kainate . DNQX, which explains published experimental data on GluR2 activation and antagonism strength.
Explaining RANKL inhibition by OPG through quantum biochemistry computations an...
Sousa, Bruno Lopes de; Barroso Neto, Ito Liberato; Oliveira, Evanildo Ferreira; Fonseca, Emerson Alberto da; Lima Neto, Pedro de; Ladeira, Luiz OrlandoOsteoporosis is a degenerative disease associated with excessive bone resorption, a natural process performed by osteoclasts. In turn, osteoclast maturation is critically regulated by the receptor activator of nuclear factor kB ligand (RANKL), its signalling receptor (RANK), and its decoy receptor osteoprotegerin (OPG). The critical role of the protein triad, RANK–RANKL–OPG, in osteoclastogenesis has made their...