The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jicai Feng - One of the best experts on this subject based on the ideXlab platform.
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effect of metal transfer mode on spatter and Arc stability in underwater flux cored wire wet welding
Journal of Manufacturing Processes, 2018Co-Authors: Yunlong Fu, Yongpeng Du, Hao Chen, Changsheng Xu, Jicai FengAbstract:Abstract The effect of metal transfer mode on spatter and Arc stability during underwater flux-cored wire wet welding at different process parameters are investigated adopting the synchronous acquisition system of X-ray image and electric signal. Two spatter modes i.e. the local droplet repelled spatter and the droplet explosion spatter were observed for the first time. The generation of the local droplet repelled spatter is attributed to the excessive and unstable repulsive forces, while the droplet explosion spatter is caused by the unstable repulsive forces and gas dynamic force. Welding spatters and Arc stability depend on the metal transfer mode. During wide-angle globular repelled transfer mode, the droplet repelled spatter mode is observed and the forming frequencies of the local droplet repelled spatter and droplet explosion spatter are higher than other transfer modes. The short-circuit explosions are observed in short-circuit explosive transfer mode, causing numerous short-circuit explosive spatters. With the increase of Arc Voltage, both the spatter loss coefficient and Voltage variation coefficient decrease firstly to the minimum at the Arc Voltage of 32 V and then increases gradually, attributed to the type and proportion of metal transfer mode.
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analysis and improvement of underwater wet welding process stability with static mechanical constraint support
Journal of Manufacturing Processes, 2018Co-Authors: Jianfeng Wang, Yunlu Jiang, Tao Zhang, Jicai FengAbstract:Abstract A process variant of underwater wet welding (UWW), i.e., mechanical constraint-assisted UWW process, was developed. Through the visual sensing of Arc bubble and welding electrical signals, the optimum parameters of mechanical constraint system were determined. Variations of Arc stability, Arc burning process, and weld morphology with Arc Voltage were investigated under the same mechanical constraint condition. Results indicated that the coefficients of variation for the two processes initially dipped to a minimum and then gradually increased to a higher value with increasing Arc Voltage, but the change rate of variation coefficient in UWW was much more pronounced than that in mechanical constraint-assisted UWW (MC-UWW). When the Arc Voltage was lower, the proportion of short circuiting process was so high. Thus, there was room for further reduction by mechanical constraint. But the further reduction room became still effective when the Arc Voltage was larger because the proportion of Arc extinction process was already large enough. Weld morphology results showed that the increment of weld penetration decreased from 0.91 mm to 0.18 mm with the increase of Arc Voltage when mechanical constraint was applied. In addition, the increment trend was very significant when Arc Voltage was within the range of 20 V to 28 V. For the welding conditions in this study, a suitable Voltage range in conjunction with optimum mechanical constraint condition can be determined to achieve a more stable welding process in MC-UWW.
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effects of processing parameters on Arc stability and cutting quality in underwater wet flux cored Arc cutting at shallow water
Journal of Manufacturing Processes, 2018Co-Authors: Duo Liu, Yaotian Yan, Ning Guo, Xiaoguo Song, Jicai FengAbstract:Abstract Arc stability and cutting quality of flux-cored Arc cutting (FCAC) process were characterized using gas-forming wire and exothermic wire. The measured values of Voltage and current fluctuated greatly during cutting process. Arc extinction phenomena was very common for underwater FCAC process. The variation coefficient of Arc Voltage and the form of Arc Voltage histogram were the best indicators to evaluate cutting process. Gas-forming wire and exothermic wire functioned differently in FCAC process. With increasing Arc Voltage, cutting process became unstable while cutting quality was improved. An increase in wire feeding speed would increase the consumption of wires, and the high proportion of Arc extinction decreased the stability of the cutting process. Low cutting speed would deteriorate cutting Arc stability. Successful cut could be achieved at all investigated cutting parameters. Cutting quality were evaluated using indexes include cut width, cut bevel angle, cut edges straightness, bridging degree and residual metal on the backside of the cut.
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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.
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metal transfer in underwater flux cored wire wet welding at shallow water depth
Materials Letters, 2015Co-Authors: Meirong Wang, Yongpeng Du, Jicai FengAbstract:Abstract The metal transfer process of underwater flux-cored wire wet welding is successfully observed by an X-ray transmission method. The relatively large retention forces acting on the droplet induced by the electromagnetic force, vaporization force, surface tension resultant force and gas flow drag force make the transfer mode as a combination of globular repelled transfer mode and short circuit transfer mode with the average transfer frequency of 4.3 Hz with Arc Voltage of 24 V and welding current of 240 A.
Yongpeng Du - One of the best experts on this subject based on the ideXlab platform.
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effect of metal transfer mode on spatter and Arc stability in underwater flux cored wire wet welding
Journal of Manufacturing Processes, 2018Co-Authors: Yunlong Fu, Yongpeng Du, Hao Chen, Changsheng Xu, Jicai FengAbstract:Abstract The effect of metal transfer mode on spatter and Arc stability during underwater flux-cored wire wet welding at different process parameters are investigated adopting the synchronous acquisition system of X-ray image and electric signal. Two spatter modes i.e. the local droplet repelled spatter and the droplet explosion spatter were observed for the first time. The generation of the local droplet repelled spatter is attributed to the excessive and unstable repulsive forces, while the droplet explosion spatter is caused by the unstable repulsive forces and gas dynamic force. Welding spatters and Arc stability depend on the metal transfer mode. During wide-angle globular repelled transfer mode, the droplet repelled spatter mode is observed and the forming frequencies of the local droplet repelled spatter and droplet explosion spatter are higher than other transfer modes. The short-circuit explosions are observed in short-circuit explosive transfer mode, causing numerous short-circuit explosive spatters. With the increase of Arc Voltage, both the spatter loss coefficient and Voltage variation coefficient decrease firstly to the minimum at the Arc Voltage of 32 V and then increases gradually, attributed to the type and proportion of metal transfer mode.
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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.
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metal transfer in underwater flux cored wire wet welding at shallow water depth
Materials Letters, 2015Co-Authors: Meirong Wang, Yongpeng Du, Jicai FengAbstract:Abstract The metal transfer process of underwater flux-cored wire wet welding is successfully observed by an X-ray transmission method. The relatively large retention forces acting on the droplet induced by the electromagnetic force, vaporization force, surface tension resultant force and gas flow drag force make the transfer mode as a combination of globular repelled transfer mode and short circuit transfer mode with the average transfer frequency of 4.3 Hz with Arc Voltage of 24 V and welding current of 240 A.
F Hofmann - One of the best experts on this subject based on the ideXlab platform.
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pulsed current gas metal Arc welding under different shielding and pulse parameters part 2 behaviour of metal transfer
Isij International, 2009Co-Authors: P.k. Ghosh, Lutz Dorn, K Devakumaran, F HofmannAbstract:The behaviour of metal transfer and Arc stiffness understood in terms of Arc pressure (Pa) of pulsed current gas metal Arc welding (P-GMAW) using mild steel filler wire have been studied with respect to change in pulse parameters under different gas shieldings of Ar+2%CO2 and Ar+18%CO2. The Arc environment revealing the droplet transfer from electrode to weld pool in bead on plate weld deposition has been studied by high speed video graphy. Effect of pulse parameters has been considered by their hypothetically proposed summarized influence defined by a dimensionless factor φ, mean current (Im) and Arc Voltage. The droplet diameter and velocity of droplet at the time of detachment are found to vary significantly with the variation of φ. At a given φ the experimentally measured behaviour of metal transfer is found well in agreement to their corresponding theoretical estimates. The average droplet diameter transferred per pulse predominantly reduces but, the velocity of metal transfer at the time of detachment enhances with the increase of φ under both the shielding gases. In general a higher values of φ, Im and Arc Voltage enhances the Pa depending upon type of gas shielding. The use of Ar+2%CO2 shielding gas reduces the droplet diameter and enhances the Arc pressure than that observed under Ar+18%CO2 gas shielding.
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pulsed current gas metal Arc welding under different shielding and pulse parameters part 1 Arc characteristics
Isij International, 2009Co-Authors: P.k. Ghosh, Lutz Dorn, K Devakumaran, F HofmannAbstract:The variation of Arc characteristics with respect to its profile under Ar+2%CO2, Ar+18%CO2 and argon gas shielding and the stability of gas shielding with variation in pulse parameters have been studied by video-graphy of Arc environment during P-GMA weld deposition using mild steel filler wire. The effect of pulse parameters has been studied by considering their hypothetically proposed summarized influence defined by a dimensionless factor, φ=[(Ib/Ip)ftb], mean current and Arc Voltage. The measured root diameter, projected diameter and length have been measured and correlated to the P-GMA welding parameters under different gas shielding. It has been observed that the Arc characteristics with respect to its shape and spreading over the weld significantly vary with φ, mean current and Arc Voltage giving due consideration to the shielding environment. The use of Ar+2%CO2 gas shielding appreciably reduces the DR but enhances the DP and L with respect to that observed under Ar+18%CO2 and argon gas shielding.
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Arc characteristics and behaviour of metal transfer in pulsed current GMA welding of stainless steel
Journal of Materials Processing Technology, 2009Co-Authors: P.k. Ghosh, Shrirang Kulkarni, Lutz Dorn, F HofmannAbstract:The variation in Arc characteristics, stability in shielding of Arc environment and behaviour of metal transfer with a change in pulse parameters have been studied by high speed video-photography during pulsed current gas metal Arc (P-GMA) weld deposition using austenitic stainless steel filler wire. A comparative study of similar nature has also been carried out during gas metal Arc (GMA) weld deposition in globular and spray transfer modes. The effect of pulse parameters has been studied by considering their hypothetically proposed summarized influence defined by a dimensionless factor φ{symbol} = [(Ib/Ip) ftb], mean current and Arc Voltage and correlation between welding parameters and Arc characteristics have been established. The Arc characteristics studied by its root diameter, projected diameter, length and stiffness measured in terms of Arc pressure and the behaviour of metal transfer noted by the droplet diameter and velocity of droplet at the time of detachment have been found to vary significantly with the variation in φ{symbol}. At a given φ{symbol} the experimentally measured values of the behaviour of metal transfer are found well in agreement to their corresponding theoretical values estimated through mathematical expressions reported earlier. The increase of φ{symbol} and the ratio of (Ib/Ip) have been found to adversely affect the stability of shielding jacket and Arc profile especially at high Arc Voltage. © 2008.
Meirong Wang - One of the best experts on this subject based on the ideXlab platform.
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metal transfer in underwater flux cored wire wet welding at shallow water depth
Materials Letters, 2015Co-Authors: Meirong Wang, Yongpeng Du, Jicai FengAbstract:Abstract The metal transfer process of underwater flux-cored wire wet welding is successfully observed by an X-ray transmission method. The relatively large retention forces acting on the droplet induced by the electromagnetic force, vaporization force, surface tension resultant force and gas flow drag force make the transfer mode as a combination of globular repelled transfer mode and short circuit transfer mode with the average transfer frequency of 4.3 Hz with Arc Voltage of 24 V and welding current of 240 A.
P.k. Ghosh - One of the best experts on this subject based on the ideXlab platform.
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pulsed current gas metal Arc welding under different shielding and pulse parameters part 2 behaviour of metal transfer
Isij International, 2009Co-Authors: P.k. Ghosh, Lutz Dorn, K Devakumaran, F HofmannAbstract:The behaviour of metal transfer and Arc stiffness understood in terms of Arc pressure (Pa) of pulsed current gas metal Arc welding (P-GMAW) using mild steel filler wire have been studied with respect to change in pulse parameters under different gas shieldings of Ar+2%CO2 and Ar+18%CO2. The Arc environment revealing the droplet transfer from electrode to weld pool in bead on plate weld deposition has been studied by high speed video graphy. Effect of pulse parameters has been considered by their hypothetically proposed summarized influence defined by a dimensionless factor φ, mean current (Im) and Arc Voltage. The droplet diameter and velocity of droplet at the time of detachment are found to vary significantly with the variation of φ. At a given φ the experimentally measured behaviour of metal transfer is found well in agreement to their corresponding theoretical estimates. The average droplet diameter transferred per pulse predominantly reduces but, the velocity of metal transfer at the time of detachment enhances with the increase of φ under both the shielding gases. In general a higher values of φ, Im and Arc Voltage enhances the Pa depending upon type of gas shielding. The use of Ar+2%CO2 shielding gas reduces the droplet diameter and enhances the Arc pressure than that observed under Ar+18%CO2 gas shielding.
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pulsed current gas metal Arc welding under different shielding and pulse parameters part 1 Arc characteristics
Isij International, 2009Co-Authors: P.k. Ghosh, Lutz Dorn, K Devakumaran, F HofmannAbstract:The variation of Arc characteristics with respect to its profile under Ar+2%CO2, Ar+18%CO2 and argon gas shielding and the stability of gas shielding with variation in pulse parameters have been studied by video-graphy of Arc environment during P-GMA weld deposition using mild steel filler wire. The effect of pulse parameters has been studied by considering their hypothetically proposed summarized influence defined by a dimensionless factor, φ=[(Ib/Ip)ftb], mean current and Arc Voltage. The measured root diameter, projected diameter and length have been measured and correlated to the P-GMA welding parameters under different gas shielding. It has been observed that the Arc characteristics with respect to its shape and spreading over the weld significantly vary with φ, mean current and Arc Voltage giving due consideration to the shielding environment. The use of Ar+2%CO2 gas shielding appreciably reduces the DR but enhances the DP and L with respect to that observed under Ar+18%CO2 and argon gas shielding.
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Arc characteristics and behaviour of metal transfer in pulsed current GMA welding of stainless steel
Journal of Materials Processing Technology, 2009Co-Authors: P.k. Ghosh, Shrirang Kulkarni, Lutz Dorn, F HofmannAbstract:The variation in Arc characteristics, stability in shielding of Arc environment and behaviour of metal transfer with a change in pulse parameters have been studied by high speed video-photography during pulsed current gas metal Arc (P-GMA) weld deposition using austenitic stainless steel filler wire. A comparative study of similar nature has also been carried out during gas metal Arc (GMA) weld deposition in globular and spray transfer modes. The effect of pulse parameters has been studied by considering their hypothetically proposed summarized influence defined by a dimensionless factor φ{symbol} = [(Ib/Ip) ftb], mean current and Arc Voltage and correlation between welding parameters and Arc characteristics have been established. The Arc characteristics studied by its root diameter, projected diameter, length and stiffness measured in terms of Arc pressure and the behaviour of metal transfer noted by the droplet diameter and velocity of droplet at the time of detachment have been found to vary significantly with the variation in φ{symbol}. At a given φ{symbol} the experimentally measured values of the behaviour of metal transfer are found well in agreement to their corresponding theoretical values estimated through mathematical expressions reported earlier. The increase of φ{symbol} and the ratio of (Ib/Ip) have been found to adversely affect the stability of shielding jacket and Arc profile especially at high Arc Voltage. © 2008.