The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Emanuel Dos B F Santos - One of the best experts on this subject based on the ideXlab platform.
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application of cold wire Gas Metal Arc welding for narrow gap welding ngw of high strength low alloy steel
Materials, 2019Co-Authors: R. A. Ribeiro, Eduardo Magalhães Braga, Paulo Dangelo Costa Assuncao, Emanuel Dos B F Santos, Ademir Angelo Castro Filho, Adrian P. GerlichAbstract:Narrow gap welding is a prevalent technique used to decrease the volume of molten Metal and heat required to fill a joint. Consequently, deleterious effects such as distortion and residual stresses may be reduced. One of the fields where narrow groove welding is most employed is pipeline welding where misalignment, productivity and mechanical properties are critical to a successful final assemblage of pipes. This work reports the feasibility of joining pipe sections with 4 mm-wide narrow gaps machined from API X80 linepipe using cold wire Gas Metal Arc welding. Joints were manufactured using the standard Gas Metal Arc welding and the cold wire Gas Metal Arc welding processes, where high speed imaging, and voltage and current monitoring were used to study the Arc dynamic features. Standard Metallographic procedures were used to study sidewall penetration, and the evolution of the heat affected zone during welding. It was found that cold wire injection stabilizes the Arc wandering, decreasing sidewall penetration while almost doubling deposition. However, this also decreases penetration, and incomplete penetration was found in the cold wire specimens as a drawback. However, adjusting the groove geometry or changing the welding parameters would resolve this penetration issue.
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residual stresses in cold wire Gas Metal Arc welding
Science and Technology of Welding and Joining, 2017Co-Authors: E S Costa, Paulo Dangelo Costa Assuncao, Emanuel Dos B F Santos, L G Feio, M S Q Bittencourt, Eduardo Magalhães BragaAbstract:ABSTRACTThis work compares the welding residual stresses of the cold-wire Gas Metal Arc welding and conventional Gas Metal Arc welding processes. Two techniques were used to measure the residual stresses: X-ray diffraction and acoustic birefringence. The base Metal used was carbon manganese steel plates of 9.5- mm thickness. The results showed that the introduction of the cold-wire tends to decrease the residual stresses, suggesting that the introduction of the cold wire decreases the amount of heat given to the base Metal, and consequently lowers residual stresses.
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high frequency pulsed Gas Metal Arc welding gmaw p the Metal beam process
Manufacturing letters, 2017Co-Authors: Emanuel Dos B F Santos, Rob Pistor, A P GerlichAbstract:Abstract The characteristics of a pulsed Gas Metal Arc welding (GMAW-P) process that simultaneously achieves streaming transfer and low Arc length are described. The process uses a nearly square shaped current profile. It was found that when high pulse frequency pulses are used with high peak and low background current, stream Metal transfer is achieved at short Arc lengths. Stable streaming transfer was accomplished at a wire feeding speeds of 13.97 m/min with heat input as low as 0.58 kJ/mm. Therefore, a high productivity welding process with potential advantages for narrow groove welding of heat sensitive materials is presented.
Adrian P. Gerlich - One of the best experts on this subject based on the ideXlab platform.
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application of cold wire Gas Metal Arc welding for narrow gap welding ngw of high strength low alloy steel
Materials, 2019Co-Authors: R. A. Ribeiro, Eduardo Magalhães Braga, Paulo Dangelo Costa Assuncao, Emanuel Dos B F Santos, Ademir Angelo Castro Filho, Adrian P. GerlichAbstract:Narrow gap welding is a prevalent technique used to decrease the volume of molten Metal and heat required to fill a joint. Consequently, deleterious effects such as distortion and residual stresses may be reduced. One of the fields where narrow groove welding is most employed is pipeline welding where misalignment, productivity and mechanical properties are critical to a successful final assemblage of pipes. This work reports the feasibility of joining pipe sections with 4 mm-wide narrow gaps machined from API X80 linepipe using cold wire Gas Metal Arc welding. Joints were manufactured using the standard Gas Metal Arc welding and the cold wire Gas Metal Arc welding processes, where high speed imaging, and voltage and current monitoring were used to study the Arc dynamic features. Standard Metallographic procedures were used to study sidewall penetration, and the evolution of the heat affected zone during welding. It was found that cold wire injection stabilizes the Arc wandering, decreasing sidewall penetration while almost doubling deposition. However, this also decreases penetration, and incomplete penetration was found in the cold wire specimens as a drawback. However, adjusting the groove geometry or changing the welding parameters would resolve this penetration issue.
K Zangenehmadar - One of the best experts on this subject based on the ideXlab platform.
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study of welding velocity and pulse frequency on microstructure and mechanical properties of pulsed Gas Metal Arc welded high strength low alloy steel
Materials & Design, 2013Co-Authors: M Mirzaei, Arabi R Jeshvaghani, A Yazdipour, K ZangenehmadarAbstract:Abstract The microstructure analysis and mechanical properties evaluation of pulsed Gas Metal Arc and conventional Gas Metal Arc welded high strength low alloy (HSLA) steel joints were investigated. Welding was carried out at welding velocity of 10 and 15 cm/min and pulse frequency of 50 and 100 Hz. The joints were subjected to optical microscope, scanning electron microscope, hardness, tensile test and Charpy impact toughness testing. Results showed that at high welding velocity the microstructure of the weld Metal consisted mainly of acicular ferrite and lath martensite. At low welding velocity, small amounts of allotriomorphic and Widmanstatten ferrite were also observed. Results also showed that good mechanical properties can be obtained through the pulsed Gas Metal Arc welding with welding velocity of 15 cm/min and pulse frequency of 50 Hz. Furthermore, with decreasing of welding velocity and increasing of the pulse frequency, impact energy decreased. This can be attributed to the formation of grain boundary ferrite and higher volume fraction of inclusion in weld Metal. Results of fractography showed ductile fracture as a result of the equiaxed microvoids.
T Debroy - One of the best experts on this subject based on the ideXlab platform.
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special features of double pulsed Gas Metal Arc welding
Journal of Materials Processing Technology, 2018Co-Authors: Leilei Wang, T DebroyAbstract:Abstract Since the pulsation of heat input provides a flexible and effective way to control temporal variation of weld pool geometry, cooling rate and solidification parameters, double pulsed (DP) Gas Metal Arc welding (GMAW) serves as an unique tool for controlling the structure and properties of welds. A comprehensive model of DP-GMAW, when adequately tested with experimental data, provides a powerful tool for achieving predictable, high-quality welds. Here we develop a three-dimensional, transient, numerical model of DP-GMAW and test it against carefully planned experiments. The variation of current amplitude enables tailoring of weld attributes such as geometry, cooling rates, solidification parameters and microstructure and its role in the welding of an aluminum alloy is examined both experimentally and theoretically. Since the grain size in the fusion zone is significantly affected by its cooling rate, experimental measurements of grain size for various current amplitudes are correlated with the corresponding computed cooling rates at a constant heat input. Results indicate that cooling rates can be increased and grain size can be refined at a constant heat input while using DP-GMAW. The current amplitude of DP-GMAW can be used to adjust the average cooling rate without changing the heat input. The effects of current amplitude on the fusion zone geometry, cooling rates, solidification parameters, and grain size are investigated for improved understanding of DP-GMAW.
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a pathway to microstructural refinement through double pulsed Gas Metal Arc welding
Scripta Materialia, 2017Co-Authors: Leilei Wang, T DebroyAbstract:Abstract In fusion welding, variations of cooling rate and microstructure are commonly achieved by changing heat input. Here we show that the cooling rates can be adjusted and microstructural features could be refined at constant heat input while changing the pulsing parameters. The temporal variations of cooling rates, solidification growth rate and weld geometry during both single and double pulsed welding of an aluminum alloy are examined. Furthermore, microstructures of both single and double pulsed Gas Metal Arc welding are presented to demonstrate significant microstructural refinement of double pulsed Gas Metal Arc welds for the same heat input.
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heat and fluid flow in complex joints during Gas Metal Arc welding part ii application to fillet welding of mild steel
Journal of Applied Physics, 2004Co-Authors: Wei Zhang, Cheolhee Kim, T DebroyAbstract:A numerical model described in part I [W. Zhang, C.-H. Kim, and T. DebRoy, J. Appl. Phys. 95, 5210 (2004)] was used to investigate the heat transfer and free surface flow during Gas Metal Arc fillet welding of mild steel. Dimensional analysis was used to understand the importance of heat transfer by conduction and convection and the role of various driving forces on convection in the liquid weld pool. The calculated shape and size, finger penetration characteristic and solidified surface profile of the fillet welds were in fair agreement with the experimental results for various welding conditions. The calculated cooling rates were also in good agreement with independent experimental data. The effect of welding parameters on important weld bead characteristics was quantitatively studied using the numerical model. The results reported here indicate a significant promise for understanding and control of Gas Metal Arc fillet welding processes based on fundamental principles of transport phenomena.
R. A. Ribeiro - One of the best experts on this subject based on the ideXlab platform.
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application of cold wire Gas Metal Arc welding for narrow gap welding ngw of high strength low alloy steel
Materials, 2019Co-Authors: R. A. Ribeiro, Eduardo Magalhães Braga, Paulo Dangelo Costa Assuncao, Emanuel Dos B F Santos, Ademir Angelo Castro Filho, Adrian P. GerlichAbstract:Narrow gap welding is a prevalent technique used to decrease the volume of molten Metal and heat required to fill a joint. Consequently, deleterious effects such as distortion and residual stresses may be reduced. One of the fields where narrow groove welding is most employed is pipeline welding where misalignment, productivity and mechanical properties are critical to a successful final assemblage of pipes. This work reports the feasibility of joining pipe sections with 4 mm-wide narrow gaps machined from API X80 linepipe using cold wire Gas Metal Arc welding. Joints were manufactured using the standard Gas Metal Arc welding and the cold wire Gas Metal Arc welding processes, where high speed imaging, and voltage and current monitoring were used to study the Arc dynamic features. Standard Metallographic procedures were used to study sidewall penetration, and the evolution of the heat affected zone during welding. It was found that cold wire injection stabilizes the Arc wandering, decreasing sidewall penetration while almost doubling deposition. However, this also decreases penetration, and incomplete penetration was found in the cold wire specimens as a drawback. However, adjusting the groove geometry or changing the welding parameters would resolve this penetration issue.
