Dongsheng Wu, Junhao Sun, Zhuguo Li, Jian Huang, Ke Feng
Thin copper materials are difficult to weld using infrared lasers (IR) due to their low energy absorption. A blue laser with a wavelength of 450 nm strongly increases energy absorption and successfully realized the microjoining of a copper material with a thickness of 0.1 mm. The dynamic behaviors of a thin molten pool were investigated by a numerical simulation using a new blue laser heat source model. At both the top and bottom surfaces of the thin molten pool, the liquid metal flowed outward under the driving of Marangoni stress. The stability of the thin molten pool was studied, showing that Marangoni stress promoted the melt-through of the thin molten pool, while the viscous resistant stress, buoyant force, and surface tension pressure had minor influences on it. The Peclet and Marangoni numbers were adopted to predict the stability of the thin molten pool.
{"title":"Thin Molten Pool Behaviors in Blue Laser Microjoining","authors":"Dongsheng Wu, Junhao Sun, Zhuguo Li, Jian Huang, Ke Feng","doi":"10.29391/2022.101.021","DOIUrl":"https://doi.org/10.29391/2022.101.021","url":null,"abstract":"Thin copper materials are difficult to weld using infrared lasers (IR) due to their low energy absorption. A blue laser with a wavelength of 450 nm strongly increases energy absorption and successfully realized the microjoining of a copper material with a thickness of 0.1 mm. The dynamic behaviors of a thin molten pool were investigated by a numerical simulation using a new blue laser heat source model. At both the top and bottom surfaces of the thin molten pool, the liquid metal flowed outward under the driving of Marangoni stress. The stability of the thin molten pool was studied, showing that Marangoni stress promoted the melt-through of the thin molten pool, while the viscous resistant stress, buoyant force, and surface tension pressure had minor influences on it. The Peclet and Marangoni numbers were adopted to predict the stability of the thin molten pool.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44693289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The coarse-grained heat-affected zone (CGHAZ) samples were prepared from T23 steel with three different carbon contents on a thermal simulator, then isothermal slow strain rate tensile tests were carried out at 500° ~ 750°C, and the effect of carbon content on the stress-relief cracking (SRC) sensitivity of T23 steel was evaluated according to fracture ductility. The microstructure evolution of the CGHAZs in the process of SRC was observed by optical microscopy, structural equation modeling energy-dispersive spectroscopy, and transmission electron microscopy energy-dispersive spectroscopy/selected area electron diffraction to reveal the mechanism of SRC. Finally, the feasibility of adjusting carbon content to prevent SRC was discussed. The results showed the classical theory of intragranular precipitation hardening cannot explain the cause of SRC, and a new viewpoint was put forward that the precipitation of M23C6 at the grain boundary was the main reason for SRC. The precipitation of M23C6 carbide cannot only provide a preferred site for void nucleation but also leads to the depletion of alloy elements in the matrix near the grain boundary. The interaction of these two aspects leads to the direct weakening of grain boundaries. Moreover, the SRC of T23 steel could be inhibited when the carbon content was determined to be close to the ASME standard lower limit of 0.04 wt-%. In summary, reducing the carbon content can inhibit the SRC sensitivity of T23 steel, which is not due to reducing the relative weakening of the grain boundary by reducing the precipitation hardening in the grain interior but to inhibiting the direct weakening of the grain boundary by reducing the precipitation of M23C6 at the grain boundary.
{"title":"Effect of Carbon on Stress-Relief Cracking Susceptibility of T23 Steel","authors":"Xue Wang, Dongdong Zhang, Yong Li, Xianhong Lai, Wei Zhang","doi":"10.29391/2022.101.020","DOIUrl":"https://doi.org/10.29391/2022.101.020","url":null,"abstract":"The coarse-grained heat-affected zone (CGHAZ) samples were prepared from T23 steel with three different carbon contents on a thermal simulator, then isothermal slow strain rate tensile tests were carried out at 500° ~ 750°C, and the effect of carbon content on the stress-relief cracking (SRC) sensitivity of T23 steel was evaluated according to fracture ductility. The microstructure evolution of the CGHAZs in the process of SRC was observed by optical microscopy, structural equation modeling energy-dispersive spectroscopy, and transmission electron microscopy energy-dispersive spectroscopy/selected area electron diffraction to reveal the mechanism of SRC. Finally, the feasibility of adjusting carbon content to prevent SRC was discussed. The results showed the classical theory of intragranular precipitation hardening cannot explain the cause of SRC, and a new viewpoint was put forward that the precipitation of M23C6 at the grain boundary was the main reason for SRC. The precipitation of M23C6 carbide cannot only provide a preferred site for void nucleation but also leads to the depletion of alloy elements in the matrix near the grain boundary. The interaction of these two aspects leads to the direct weakening of grain boundaries. Moreover, the SRC of T23 steel could be inhibited when the carbon content was determined to be close to the ASME standard lower limit of 0.04 wt-%. In summary, reducing the carbon content can inhibit the SRC sensitivity of T23 steel, which is not due to reducing the relative weakening of the grain boundary by reducing the precipitation hardening in the grain interior but to inhibiting the direct weakening of the grain boundary by reducing the precipitation of M23C6 at the grain boundary.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42160890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muralimohan Cheepu, Hyo Jin Baek, Young Sik Kim, Sang-Myung Cho
This study proposes a novel method to estimate the weld penetration in gas tungsten arc welding (GTAW) with filler metal. So far, there is no standard parameter available to accurately estimate penetration in GTAW with filler metal. Until now, the penetration could be estimated by heat input only in GTAW with and without filler metal. But in this study, it was revealed that the conventional heat input could not accurately estimate the penetration in GTAW with filler metal. Therefore, the new concept of net heat input ratio (NHIR), which is a ratio of net heat input to the bead cross-sectional area, was developed to accurately estimate the penetration in GTAW with filler metal. Using a C-type filler metal during GTAW, the NHIR was calculated for various welding conditions. The results showed that the NHIR was proportional to the welding current and voltage and inversely proportional to the welding speed and filler feed speed. Even though the NHIR was the same, the penetration increased as the welding current became higher. Four linear equations between NHIR and penetration were obtained from the experimental results for four levels of welding currents. By applying the concept of NHIR, the penetration could be estimated for any welding current.
{"title":"Penetration Estimation of GTAW with C-Type Filler by Net Heat Input Ratio","authors":"Muralimohan Cheepu, Hyo Jin Baek, Young Sik Kim, Sang-Myung Cho","doi":"10.29391/2022.101.018","DOIUrl":"https://doi.org/10.29391/2022.101.018","url":null,"abstract":"This study proposes a novel method to estimate the weld penetration in gas tungsten arc welding (GTAW) with filler metal. So far, there is no standard parameter available to accurately estimate penetration in GTAW with filler metal. Until now, the penetration could be estimated by heat input only in GTAW with and without filler metal. But in this study, it was revealed that the conventional heat input could not accurately estimate the penetration in GTAW with filler metal. Therefore, the new concept of net heat input ratio (NHIR), which is a ratio of net heat input to the bead cross-sectional area, was developed to accurately estimate the penetration in GTAW with filler metal. Using a C-type filler metal during GTAW, the NHIR was calculated for various welding conditions. The results showed that the NHIR was proportional to the welding current and voltage and inversely proportional to the welding speed and filler feed speed. Even though the NHIR was the same, the penetration increased as the welding current became higher. Four linear equations between NHIR and penetration were obtained from the experimental results for four levels of welding currents. By applying the concept of NHIR, the penetration could be estimated for any welding current.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46621703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coal-fired power plants often have welded joints made up of 347H stainless steel. However, this alloy is known to fail because of stress relaxation cracking. Thus, quantitative evaluation methods are needed as screening measures. In this study, a Gleeble® thermomechanical simulator was implemented in 347H and Super 304H alloy heat-affected zone (HAZ) simulation and stress relaxation testing. In the case of 347H, carbide dissolution in the HAZ reduced the hardness value and promoted grain growth. Alternatively, the respective extent of precipitate dissolution and hardness reduction in the nitrogen-containing Super 304H was relatively small. The stress relaxation tests were performed at a temperature of 700°C (1292°F), which was maintained for up to 70 h. Consequently, all 347H specimens fractured within 32 h. Furthermore, the time to rupture substantially decreased as the strain was increased from 5 to 10% and then to 15%. Additionally, the hardness near the fractured surface increased, and the plastic deformation primarily occurred near the grain boundaries. Conversely, the Super 304H specimens did not fracture during the 70-h testing period, at which time their hardness distribution was observed to still be relatively uniform. These results demonstrate that the susceptibility of stress relaxation cracking can be quantitatively determined according to the material and strain.
{"title":"Comparison of Stress Relaxation Cracking Susceptibility of Austenitic Stainless Steels","authors":"H. Lee, Bumcho Kim, Sun-Ig Hong","doi":"10.29391/2022.101.017","DOIUrl":"https://doi.org/10.29391/2022.101.017","url":null,"abstract":"Coal-fired power plants often have welded joints made up of 347H stainless steel. However, this alloy is known to fail because of stress relaxation cracking. Thus, quantitative evaluation methods are needed as screening measures. In this study, a Gleeble® thermomechanical simulator was implemented in 347H and Super 304H alloy heat-affected zone (HAZ) simulation and stress relaxation testing. In the case of 347H, carbide dissolution in the HAZ reduced the hardness value and promoted grain growth. Alternatively, the respective extent of precipitate dissolution and hardness reduction in the nitrogen-containing Super 304H was relatively small. The stress relaxation tests were performed at a temperature of 700°C (1292°F), which was maintained for up to 70 h. Consequently, all 347H specimens fractured within 32 h. Furthermore, the time to rupture substantially decreased as the strain was increased from 5 to 10% and then to 15%. Additionally, the hardness near the fractured surface increased, and the plastic deformation primarily occurred near the grain boundaries. Conversely, the Super 304H specimens did not fracture during the 70-h testing period, at which time their hardness distribution was observed to still be relatively uniform. These results demonstrate that the susceptibility of stress relaxation cracking can be quantitatively determined according to the material and strain.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49130614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new process is introduced for repair of structural components of aluminum alloys. Additive manufacturing, maintenance and repair welding, Al alloy, mechanical properties.
介绍了一种用于铝合金结构件修复的新工艺。增材制造，焊接维修保养，铝合金，机械性能。
{"title":"Wire-Based Friction Stir Additive Manufacturing toward Field Repairing","authors":"Huizi Chen, Jialin Chen, Xiangchen Meng, Yuming Xie, Yongxian Huang, Shunbi Xu, Yaobang Zhao","doi":"10.29391/2022.101.019","DOIUrl":"https://doi.org/10.29391/2022.101.019","url":null,"abstract":"A new process is introduced for repair of structural components of aluminum alloys. Additive manufacturing, maintenance and repair welding, Al alloy, mechanical properties.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41925565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One defect encountered in the fusion zone when welding aluminum alloys involves solidification cracking (i.e., the tearing apart of grain boundary liquid films at the trailing edge of the weld pool). This problem can often be mitigated by the proper selection of filler metal. Two key engineering examples, one aerospace and one maritime, where this has occurred were examined in terms of alloy development to achieve optimum mechanical properties while maintaining weldability. Specifically, base metal/filler metal systems susceptible to cracking were examined in terms of filler metal dilution. A mechanism for crack growth was presented based upon critical strain rate. Conditions needed for improved weldability through grain refinement were defined based upon the columnar-to-equiaxed solidification theory.
{"title":"Applying Solidification Theory to Aluminum Weldability and Consumable Development","authors":"C. Cross","doi":"10.29391/2022.101.016","DOIUrl":"https://doi.org/10.29391/2022.101.016","url":null,"abstract":"One defect encountered in the fusion zone when welding aluminum alloys involves solidification cracking (i.e., the tearing apart of grain boundary liquid films at the trailing edge of the weld pool). This problem can often be mitigated by the proper selection of filler metal. Two key engineering examples, one aerospace and one maritime, where this has occurred were examined in terms of alloy development to achieve optimum mechanical properties while maintaining weldability. Specifically, base metal/filler metal systems susceptible to cracking were examined in terms of filler metal dilution. A mechanism for crack growth was presented based upon critical strain rate. Conditions needed for improved weldability through grain refinement were defined based upon the columnar-to-equiaxed solidification theory.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48825883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanming Wu, J. Shan, Z. Li, Xinghua Wang, Yan Feng, Ming-lin Wang
In this study, a sine-oscillating laser was used to obtain narrow groove laser-arc hybrid welding (NGHW) of high-strength low-alloy (HSLA) steel. Then the effects of laser beam oscillation amplitude and space constraint on arc behavior, droplet transfer, weld geometry, and incomplete fusion of the weld beads were analyzed. Due to the minimum arc voltage principle and inherent arc self-regulation, when the laser did not oscillate, it was observed that the arc cathode spot was typically attached to one sidewall. As a result, the molten pool did not spread through the entire width of the gap , resulting in incomplete fusion. When the laser beam oscillated in a sinusoidal path, the energy density on both sides of the amplitude was higher than the centerline, and the aspect ratio of the weld decreased. The speed of the beam along the centerline was found to be much higher than the speed on both sides of the amplitude. The molten pool oscillated in the width direction under the action of the oscillating beam, forming a concave surface, which promoted melting of the sidewalls of the groove and suppressed incomplete fusion defects in the sidewalls. The technical feasibility of NGHW assisted by laser beam oscillation was verified using a 60-mm-thick weld, which was haracterized by a smooth layer transition and the absence of visible defects.
{"title":"•Narrow Groove Laser-Arc Hybrid Welding of Thick-Sectioned HSLA Steel Using Laser Beam Oscillation","authors":"Yanming Wu, J. Shan, Z. Li, Xinghua Wang, Yan Feng, Ming-lin Wang","doi":"10.29391/2022.101.014","DOIUrl":"https://doi.org/10.29391/2022.101.014","url":null,"abstract":"In this study, a sine-oscillating laser was used to obtain narrow groove laser-arc hybrid welding (NGHW) of high-strength low-alloy (HSLA) steel. Then the effects of laser beam oscillation amplitude and space constraint on arc behavior, droplet transfer, weld geometry, and incomplete fusion of the weld beads were analyzed. Due to the minimum arc voltage principle and inherent arc self-regulation, when the laser did not oscillate, it was observed that the arc cathode spot was typically attached to one sidewall. As a result, the molten pool did not spread through the entire width of the gap , resulting in incomplete fusion. When the laser beam oscillated in a sinusoidal path, the energy density on both sides of the amplitude was higher than the centerline, and the aspect ratio of the weld decreased. The speed of the beam along the centerline was found to be much higher than the speed on both sides of the amplitude. The molten pool oscillated in the width direction under the action of the oscillating beam, forming a concave surface, which promoted melting of the sidewalls of the groove and suppressed incomplete fusion defects in the sidewalls. The technical feasibility of NGHW assisted by laser beam oscillation was verified using a 60-mm-thick weld, which was haracterized by a smooth layer transition and the absence of visible defects.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44891331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During resistance spot welding of zinc-coated advanced high-strength steels (AHSSs) for automotive production, liquid metal embrittlement (LME) cracking may occur in the event of a combination of various unfavorable influences. In this study, the interactions of different welding current levels and weld times on the tendency for LME cracking in third-generation AHSSs were investigated. LME manifested itself as high-penetration cracks around the circumference of the spot welds for welding currents closely below the expulsion limit. At the same time, the observed tendency for LME cracking showed no direct correlation with the overall heat input of the investigated welding processes. To identify a reliable indicator of the tendency for LME cracking, the local strain rate at the origin of the observed cracks was analyzed over the course of the welding process via finite element simulation. While the local strain rate showed a good correlation with the process-specific LME cracking tendency, it was difficult to interpret due to its discontinuous course. Therefore, based on the experimental measurement of electrode displacement during welding, electrode indentation velocity was proposed as a descriptive indicator for quantifying cracking tendency.
{"title":"The Influence of Electrode Indentation Rate on LME Formation during RSW","authors":"C. Böhne, G. Meschut, M. Biegler, M. Rethmeier","doi":"10.29391/2022.101.015","DOIUrl":"https://doi.org/10.29391/2022.101.015","url":null,"abstract":"During resistance spot welding of zinc-coated advanced high-strength steels (AHSSs) for automotive production, liquid metal embrittlement (LME) cracking may occur in the event of a combination of various unfavorable influences. In this study, the interactions of different welding current levels and weld times on the tendency for LME cracking in third-generation AHSSs were investigated. LME manifested itself as high-penetration cracks around the circumference of the spot welds for welding currents closely below the expulsion limit. At the same time, the observed tendency for LME cracking showed no direct correlation with the overall heat input of the investigated welding processes. To identify a reliable indicator of the tendency for LME cracking, the local strain rate at the origin of the observed cracks was analyzed over the course of the welding process via finite element simulation. While the local strain rate showed a good correlation with the process-specific LME cracking tendency, it was difficult to interpret due to its discontinuous course. Therefore, based on the experimental measurement of electrode displacement during welding, electrode indentation velocity was proposed as a descriptive indicator for quantifying cracking tendency.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46737831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To further understand the structure-parameter-property relationships of friction stir welded aluminum alloy joints, a nested neural network was proposed to map the macro- and microstructural response. The uncoupled effect of each primitive parameter on the joint performance was depicted. Reducing heat input and keeping an adequate load-bearing area of the welding nugget zone were proven to be the sufficient and necessary conditions to obtain high load-bearing performance. The entire-process simulation strategy showed great potential for prediction and optimization of the macro- and microstructural response of complex and large components.
{"title":"Entire-Process Simulation of Friction Stir Welding — Part 2: Implementation of Neural Networks","authors":"Yuming Xie, Xiangchen Meng, Yongxian Huang","doi":"10.29391/2022.101.013","DOIUrl":"https://doi.org/10.29391/2022.101.013","url":null,"abstract":"To further understand the structure-parameter-property relationships of friction stir welded aluminum alloy joints, a nested neural network was proposed to map the macro- and microstructural response. The uncoupled effect of each primitive parameter on the joint performance was depicted. Reducing heat input and keeping an adequate load-bearing area of the welding nugget zone were proven to be the sufficient and necessary conditions to obtain high load-bearing performance. The entire-process simulation strategy showed great potential for prediction and optimization of the macro- and microstructural response of complex and large components.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48334713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zihan Li, Jianwen Xin, Xueming Hua, Dongsheng Wu, S. Tashiro, Manabu Tanaka, Huan Wang
A three-dimensional coupled tungsten electrode–plasma arc–metal vapor– weld pool model was developed to investigate plasma arc and metal vapor characteristics, weld pool convection, and energy transfer in conduction plasma arc lap welding. The arc energy efficiency was also calculated. The numerical results showed that in conduction plasma arc lap welding, the constraint effects of the plasma arc by a small constricting nozzle, plasma gas, and electromagnetic force were strong, and no keyhole was formed inside the weld pool, so the heat flux on the weld pool surface was high as well as the weld pool temperature and mole fraction of Fe vapor above the weld pool surface. The high concentration of Fe vapor in the arc decreased the conduction energy from the plasma arc to the weld pool along with the arc energy efficiency. The calculated arc energy efficiency was only 50.2%. Without considering Fe vapor, the calculated weld pool had complete joint penetration. When considering Fe vapor, the calculated weld geometry agreed well with the experimental result.
{"title":"Influence Mechanism of Metal Vapor in Plasma Arc Lap Welding","authors":"Zihan Li, Jianwen Xin, Xueming Hua, Dongsheng Wu, S. Tashiro, Manabu Tanaka, Huan Wang","doi":"10.29391/2022.101.012","DOIUrl":"https://doi.org/10.29391/2022.101.012","url":null,"abstract":"A three-dimensional coupled tungsten electrode–plasma arc–metal vapor– weld pool model was developed to investigate plasma arc and metal vapor characteristics, weld pool convection, and energy transfer in conduction plasma arc lap welding. The arc energy efficiency was also calculated. The numerical results showed that in conduction plasma arc lap welding, the constraint effects of the plasma arc by a small constricting nozzle, plasma gas, and electromagnetic force were strong, and no keyhole was formed inside the weld pool, so the heat flux on the weld pool surface was high as well as the weld pool temperature and mole fraction of Fe vapor above the weld pool surface. The high concentration of Fe vapor in the arc decreased the conduction energy from the plasma arc to the weld pool along with the arc energy efficiency. The calculated arc energy efficiency was only 50.2%. Without considering Fe vapor, the calculated weld pool had complete joint penetration. When considering Fe vapor, the calculated weld geometry agreed well with the experimental result.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41604280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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