47 documents found, page 1 of 5
Naphthenic Corrosion Resistance, Mechanical Properties and Microstructure Evolu...
Moura, Lorena Braga; Guimarães, Rodrigo Freitas; Abreu, Hamilton Ferreira Gomes de; Miranda, Hélio Cordeiro de; Tavares, Sérgio Souto MaiorOne method to face the effects of naphthenic acid corrosion in petroleun refining plants is to use alloys with good resistance to this kind of corrosion. For this purpose, molybdenum additions to chromium containing steels are specially recommended. In this work, experimental Fe-9Cr-xMo (x = 5, 7 and 9 wt. (%)) ingots were cast, forged and hot rolled before being tested in a naphthenic acid environment. Evoluti...
Thermodynamic stacking fault energy, chemical composition, and microstructure r...
Ribamar, Giovani Gonçalves; Andrade, Tathiane Caminha; Miranda, Hélio Cordeiro de; Abreu, Hamilton Ferreira Gomes deStacking fault energy (SFE) is related to activating complex high strength and ductility mechanisms such as transformation-induced plasticity and twinning-induced plasticity effects. This type of energy can be estimated by many different methods and its importance is in its ability to predict microstructure and phase transformation behavior when the material is submitted to stress/strain. In order to study the ...
Simulations in multipass welds using low transformation temperature filler mate...
Novotný, Ladislav; Abreu, Hamilton Ferreira Gomes de; Miranda, Hélio Cordeiro de; Béreš, MiloslavTransient thermal and residual stress fields in flux-cored arc welds were examined using a finite element (FE) model. Experimental multipass welds were produced using both conventional and low transformation temperature (LTT) filler metals. Temperature-dependent material properties and both convective and radiant heat loss boundary condition have been considered in the FE model. The effects of the transformatio...
Estudo de procedimentos de soldagem MIG/MAG para aplicação de revestimentos de ...
Cavalcante, Nathália Escóssio; Andrade, Tathiane Caminha; Pinheiro, Pedro Helton Magalhães; Miranda, Hélio Cordeiro de; Motta, Marcelo FerreiraThis work aims to study welding techniques applied to repair of components made of ASTM A387 Gr.11 steel, widely used in the oil and gas industry. Due to the working conditions it is needed use materials having good strength and corrosion resistance. UNS N06625 Ni-based alloy (Inconel 625) was used as the filler metal. MIG / MAG welding process was used to apply the temper bead welding technique with two layers...
Utilização do equipamento de ensaio epr-dl de campo na detecção de fase sigma u...
Barreto, Abraão Danilo Gomes; Andrade, Tathiane Caminha; Silva, Cleiton Carvalho; Miranda, Hélio Cordeiro deThis work has objective to correlate the intergranular corrosion susceptibility test named EPR-DL (Electrochemical Potentiokinetic Reactivation of Double Loop) with the sigma phase formation and other phases. It has been used samples from a UNS S32760 steel pipe for conducting various aging heat treatments. Held isothermal heat treatment at 850°C for 1 min, 10 min, 30 min, 1 h, 1h30min and 10 h. Each heat treat...
Efeito dos diferentes teores de molibdênio nas propriedades mecânicas de ligas ...
Saboia, Fernando Henrique Costa; Pinheiro, Víctor Moita; Guimarães, Rodrigo Freitas; Miranda, Hélio Cordeiro de; Abreu, Hamilton Ferreira Gomes deThe aim of this study was to determine the mechanical properties of three experimental alloys with 9% Cr and Mo content with 5%, 7% and 9%. We carried out mechanical tests to determine the mechanical properties of alloys by hardness testing, tensile testing and impact testing.After microstructural analysis was performed measuring microhardness. Specimens were machined for tensile testing at room temperature. We...
Estudo dos efeitos da restrição na microestrutura, microdureza e tenacidade em ...
Nunes, Everton Barbosa; Motta, Marcelo Ferreira; Abreu, Hamilton Ferreira Gomes de; Farias, Jesualdo Pereira; Miranda, Hélio Cordeiro deDuplex stainless steels present ferrite and austenite in their microstructure in order to join good mechanical properties and corrosion resistance. These materials are very used in petrochemical industry, being the DSS UNS S31803 one of the most commercially known. There were not much published literature to study the influence of the precipitation of Widmanstätten austenite in joins with some restriction. This...
Influência do teor de Mo na microestrutura de Ligas Fe-9Cr-xMo
Guimarães, Rodrigo Freitas; Figueiredo, Nathália Cândido; Pinheiro, Víctor Moita; Miranda, Hélio Cordeiro de; Abreu, Hamilton Ferreira Gomes deCr-Mo steels are used in the petroleum industry in applications with crude oils rich in sulfur compounds. 2.5Cr1Mo or 9Cr1Mo do not resist to operating conditions when in contact with crude oils. The increasing of molybdenum content can improve the corrosion resistance of these alloys. This paper studied the effect of increased concentration of molybdenum in the microstructure of Fe-9Cr-xMo alloys, annealed and...
Seleção de parâmetros através do método Taguchi para soldagem de revestimento c...
Pessoa, Antônio Rodolfo Paulino; Miranda, Hélio Cordeiro de; Farias, Jesualdo Pereira; Aguiar, Willys Machado; Assis Filho, Francisco deIn this work aim the Taguchi method (Robust design of experiments) was chosen to achieve with a limited number of tests two objectives: the first was to the influence of the control factors (welding parameters) on quality characteristics (weld bead geometry) and the second was to determine optimal conditions for weld overlay with nickel alloy through the GMAW process in a short circuiting transfer mode. Six con...
Avaliação do efeito da energia de soldagem sobre as tensões residuais resultant...
Oliveira, George Luiz Gomes de; Silva, Thiago Ferreira da; Miranda, Hélio Cordeiro de; Motta, Marcelo FerreiraThe energy input in welding can be adjusted by either control of welding power (voltage and welding current) or welding speed. These different ways of changing can result in different residual stress profiles in the welded joint. Then, the aim of this work is to evaluate, in an independent way, the welding energy input, current and speed effect on the final residual stresses of a multipass joint. Semi-v chamfer...