Acicular Ferrite
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Influência do Regime Transiente Sobre a Microdureza e Microestrutura nos Aços ASTM-A36 e SAE-1045 Soldados pelo Processo MAG
Resumo O regime quase-estacionário pode não ser alcançado em soldagens a arco elétrico de peças de pequenas dimensões e/ou de materiais de maior condutividade térmica. Entretanto, o regime transiente sempre ocorrerá no início e no final da soldagem. Neste regime, a variação do fluxo de energia via calor pode promover variações microestruturais e
Soldag. insp.. Publicado em: 08/08/2019
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2. Influence of Niobium and Molybdenum on Mechanical Strength and Wear Resistance of Microalloyed Steels
The HSLA (High-Strength Low Alloy) steels are used in the production of pipes, flanges and connectors to build ducts for ore, oil and gas transport. The conventional processes are the rolling or forging. In the transport of ore and heavy oil, the abrasive particles impair the surfaces and reduce the pipelines lifetime. Therefore, besides the mechanical prope
Mat. Res.. Publicado em: 05/06/2017
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3. The Analysis of the Microstructure and Mechanical Properties of Low Carbon Microalloyed Steels after Ultra Fast Cooling
In this paper, two low carbon microalloyed steels, named as steel A and steel B, were fabricated by ultra fast cooling (UFC). In both steels, the microstructures containing quasi polygonal ferrite (QF), acicular ferrite (AF) and granular bainite (GB) can be obtained by UFC process. The amount of AF in steel B is more than that in steel A. The size and distri
Mat. Res.. Publicado em: 18/05/2017
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4. Study of Pipeline Steels with Acicular Ferrite Microstructure and Ferrite-bainite Dual-phase Microstructure
Three kinds of X70 steels with the same chemical composition and different microstructures fabricated by varying processes were compared in aspect of the microstructures and mechanical properties using SEM, TEM and tensile testing machine. The experimental results showed that the steel 1 with acicular ferritic microstructure fabricated by thermal-mechanical
Mat. Res.. Publicado em: 2015-02
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5. Microstructure and mechanical properties of two Api steels for iron ore pipelines
This research compares the mechanical behavior of two API steels (X60 and X70) used in the longest pipeline in the world for the conveyance of iron ore. Tensile tests, Charpy impact tests, CTOD tests and fatigue crack growth tests are performed at ambient temperature. Metallographic examination showed a banded microstructure consisting of polygonal ferrite a
Mat. Res.. Publicado em: 27/05/2014
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6. Study of phase transformations In API 5L X80 Steel in order to increase its fracture toughness
Phase transformations in API 5L X80 steel were studied in different thermomechanical sequences with a view to increasing the fracture toughness of this steel. Dilatometry tests performed on the quenched steel detected a phase transformation occurred, during heating, in the temperature range 593-618 K. This phase transformation was identified as the dissoluti
Mat. Res.. Publicado em: 19/02/2013
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7. Effect of initial microstructures on the properties of Ferrite-Martensite Dual-Phase pipeline steels with Strain-Based design
This study aims to investigate the effect of initial microstructures on the properties of ferrite-martensite dual-phase pipeline steels with strain-based design. For this purpose, the as-received acicular ferrite steels were first austenitized at 920 ºC for 15 minutes followed by air cooling and water quenching to produce ferrite-pearlite and ferrite-marten
Materials Research. Publicado em: 29/02/2012
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8. Influencia de la cantidad de O2 adicionado al CO2 en el gas de protección sobre la microestructura del metal depositado en uniones soldadas de bordes rectos en aceros de bajo contenido de carbono con el proceso GMAW
The presence of acicular ferrite (AF) in the microstructure of weld bead, in a specified range of values, increase considerably the toughness of welded joints. The present paper, for that reason, study the relationship between the acicular ferrite quantity in the deposited metal and the oxygen present in the active gas mixture of CO2+O2, during the execution
Soldagem & Inspeção. Publicado em: 2010-12
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9. Effect of thermo-mechanical parameters on microstructure and mechanical properties of microalloyed steels
In this work the effects of controlled rolling parameters and adding of Niobium have been studied. In this order two steel grades with and without Niobium are planed and after steelmaking and continuous casting, rolling process are done. Then, laboratory investigations such as microstructure, mechanical properties and grain size analysis were performed Tensi
Brazilian Journal of Physics. Publicado em: 2010-12
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10. Weld-metal property optimization from flux ingredients through mixture experiments and mathematical programming approach
This paper presents a new methodology for weld-metal properties optimization from welding flux ingredients. The methodology integrates statistical design of mixture experiment with mathematical programming optimization technique. The mixture experiment is responsible for the modeling of the weld-metal properties as a function of welding flux levels while mat
Materials Research. Publicado em: 2009-09
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11. Corrosion of ASTM A 285 grade C steel welds used in celullose production by kraft process / Corrosão nas soldas do aço ASTM A 285 grau C empregados na obtenção de celulose pelo método Kraft
In this work samples of ASTM A 285 Grade C class steel, welded with covered electrodes AWS E7018 and AWS E6013, and with variations in the welding energy, were tested electrochemically, immersed in alkaline liquor, which is used in Kraft batch digesters. Workpieces were cut by electroerosion process from base metal (MB), heat affected zone (ZTA) and weld met
Publicado em: 2007
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12. Aplicação de ensaio de impacto Charpy instrumentado no estudo da tenacidade à fratura dinâmica nas soldas a arco submerso em aços para caldeiras / Instrumented Charpy impact test application in the dynamic fracture toughness study by submerged arc welds at steel for boilers
A utilização do eletrodo tubular no processo de soldagem a arco submerso leva a um aumento na produtividade com um custo relativamente baixo, pois não requer investimentos complementares em equipamentos. A mudança do eletrodo sólido para o tubular acarreta variações microestruturais no metal de solda que influenciam as propriedades mecânicas, tais co
Publicado em: 2004