The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Zongquan Deng - One of the best experts on this subject based on the ideXlab platform.
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study of underwater wet welding stability using an x ray transmission method
Journal of Materials Processing Technology, 2015Co-Authors: Yongpeng Du, Jicai Feng, Zongquan DengAbstract:Abstract The effects of arc voltage on the stability of the underwater wet flux-cored arc welding (FCAW-S 114) process are explained based on studying the droplet transfer process using the X-ray transmission method. The mode of metal transfer and the protective bubble effect, which vary with voltage, affect the stability of the welding process. The results indicate that there is a critical arc voltage (32 V). When the arc voltage is less than 32 V, an unstable welding process occurs because of the high proportion of short-Circuit transfer and limited bubble size. Increase in the arc burning zone must be protected, and the proportion of repelled metal transfer caused by the high arc voltage decreases the stability of the welding process. In this study, stable welding process is acquired when the proportion of repelled metal transfer is less than 20%, the short Circuit Frequency is lower than 1 Hz and the bubble diameter is larger than 24 mm.
Alexandre Queiroz Bracarense - One of the best experts on this subject based on the ideXlab platform.
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Comparison of underwater wet welding performed with silicate and polymer agglomerated electrodes
Journal of Materials Processing Technology, 2019Co-Authors: Pedro Henrique Ribeiro Menezes, Ezequiel C. P. Pessoa, Alexandre Queiroz BracarenseAbstract:Abstract Conventional basic electrodes varnished and basic electrodes agglomerated with polymer in underwater wet welding in a simulated depth of 10 m were compared. A hyperbaric tank was used for depth simulation and a gravity welding device for making the bead on plate welds. Bead on plate welds were deposited with welding currents of 100, 120, 140, 160 and 180 A with DCEN and DCEP polarities, in order to evaluate the arc stability through a non-dimensional statistical index. The welding current which showed better stability level in both polarities was chosen to evaluate weld bead morphology, weld metal porosity, weld metal oxygen and diffusible hydrogen levels. A methodology was used to correlate the heat input and short-Circuit Frequency with the weld bead morphology. It was observed a direct relation with the weld metal oxygen and penetration and an inverse relation of the weld metal oxygen with the diffusible hydrogen. Electrodes agglomerated with polymer showed higher penetration values than conventional electrodes in both polarities and lowest diffusible hydrogen levels in the DCEP polarity. It was observed lower levels of weld metal porosity for the electrodes agglomerated with polymer in comparison to conventional electrodes. This result was related to lower levels of porosity found in the droplets formed at the tip of the electrodes agglomerated with polymer.
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The Effect of the Use of PTFE as a Covered-Electrode Binder on Metal Transfer
Soldagem & Inspeção, 2015Co-Authors: Cláudio Turani Vaz, Alexandre Queiroz BracarenseAbstract:Studies have shown that when used as binders for basic covered electrodes, polymers produce a weld metal microstructure with a high acicular ferrite content. The reasons identified for this behavior include changes in the shielding atmosphere and metal transfer mode. To investigate the effect of polymers on metal transfer, voltage oscillograms and high-speed films were recorded during welding with standard-binder and polymer-binder E7018 electrodes using different welding currents. Electrodes tips collected after the arc had been abruptly interrupted were examined metallographically. For electrodes with a polymer binder, the short-Circuit Frequency was lower regardless of the welding current used and decreased as welding current increased. In many events characterized as short Circuits in the voltage oscillograms for polymer-binder electrodes, metal transfer in fact occurred without any arc interruption. The angle between the outer edge of the metal drop and the inner edge of the coating crater showed that the polymer increased the intensity of the plasma jet, and the pinch effect observed during welding using the polymer-binder electrode indicated that there were changes in surface tension and electromagnetic force.
Yongpeng Du - One of the best experts on this subject based on the ideXlab platform.
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study of underwater wet welding stability using an x ray transmission method
Journal of Materials Processing Technology, 2015Co-Authors: Yongpeng Du, Jicai Feng, Zongquan DengAbstract:Abstract The effects of arc voltage on the stability of the underwater wet flux-cored arc welding (FCAW-S 114) process are explained based on studying the droplet transfer process using the X-ray transmission method. The mode of metal transfer and the protective bubble effect, which vary with voltage, affect the stability of the welding process. The results indicate that there is a critical arc voltage (32 V). When the arc voltage is less than 32 V, an unstable welding process occurs because of the high proportion of short-Circuit transfer and limited bubble size. Increase in the arc burning zone must be protected, and the proportion of repelled metal transfer caused by the high arc voltage decreases the stability of the welding process. In this study, stable welding process is acquired when the proportion of repelled metal transfer is less than 20%, the short Circuit Frequency is lower than 1 Hz and the bubble diameter is larger than 24 mm.
Pedro Henrique Ribeiro Menezes - One of the best experts on this subject based on the ideXlab platform.
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Comparison of underwater wet welding performed with silicate and polymer agglomerated electrodes
Journal of Materials Processing Technology, 2019Co-Authors: Pedro Henrique Ribeiro Menezes, Ezequiel C. P. Pessoa, Alexandre Queiroz BracarenseAbstract:Abstract Conventional basic electrodes varnished and basic electrodes agglomerated with polymer in underwater wet welding in a simulated depth of 10 m were compared. A hyperbaric tank was used for depth simulation and a gravity welding device for making the bead on plate welds. Bead on plate welds were deposited with welding currents of 100, 120, 140, 160 and 180 A with DCEN and DCEP polarities, in order to evaluate the arc stability through a non-dimensional statistical index. The welding current which showed better stability level in both polarities was chosen to evaluate weld bead morphology, weld metal porosity, weld metal oxygen and diffusible hydrogen levels. A methodology was used to correlate the heat input and short-Circuit Frequency with the weld bead morphology. It was observed a direct relation with the weld metal oxygen and penetration and an inverse relation of the weld metal oxygen with the diffusible hydrogen. Electrodes agglomerated with polymer showed higher penetration values than conventional electrodes in both polarities and lowest diffusible hydrogen levels in the DCEP polarity. It was observed lower levels of weld metal porosity for the electrodes agglomerated with polymer in comparison to conventional electrodes. This result was related to lower levels of porosity found in the droplets formed at the tip of the electrodes agglomerated with polymer.
Jicai Feng - One of the best experts on this subject based on the ideXlab platform.
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Study of metal transfer control in underwater wet FCAW using pulsed wire feed method
Welding in the World, 2017Co-Authors: Ning Guo, Sergii Yuri Maksimov, Jicai Feng, Ziqiang Yin, Denys KrazhanovskyiAbstract:A metal transfer control method based on pulsed wire feed technology is adopted to ameliorate the underwater flux-cored arc wet welding quality. The stability of the welding process is improved with appropriate pulse parameters. The influences of pulse parameters on the metal transfer process are clarified using an X-ray transmission method. Pulse Frequency has more of an effect on weld appearance and welding stability than pulse duty factor. Thirty to forty hertz is an appropriate Frequency bound for a stable metal transfer process. The repelled metal transfer percentage decreases with increasing droplet growth speed. The inertia force shortens the metal transfer period and prompts droplet transfer into the pool. When the pulse Frequency is less than 40 Hz, the base speed time is long enough for the inertia force to act on the droplet. But if the pulse Frequency is below 20 Hz, the peak wire feed speed will be sustained for a long time, and the short-Circuit Frequency increases from 1 to 2.5 Hz; as a result, the welding stability and the welding appearance deteriorate. For the wire employed in this study, better welding stability is obtained at 30 Hz, while the pulse duty factor is 2.
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study of underwater wet welding stability using an x ray transmission method
Journal of Materials Processing Technology, 2015Co-Authors: Yongpeng Du, Jicai Feng, Zongquan DengAbstract:Abstract The effects of arc voltage on the stability of the underwater wet flux-cored arc welding (FCAW-S 114) process are explained based on studying the droplet transfer process using the X-ray transmission method. The mode of metal transfer and the protective bubble effect, which vary with voltage, affect the stability of the welding process. The results indicate that there is a critical arc voltage (32 V). When the arc voltage is less than 32 V, an unstable welding process occurs because of the high proportion of short-Circuit transfer and limited bubble size. Increase in the arc burning zone must be protected, and the proportion of repelled metal transfer caused by the high arc voltage decreases the stability of the welding process. In this study, stable welding process is acquired when the proportion of repelled metal transfer is less than 20%, the short Circuit Frequency is lower than 1 Hz and the bubble diameter is larger than 24 mm.