Pub Date : 2023-07-03DOI: 10.1080/09507116.2023.2233889
Sanjay S. Surwase, S. Bhosle
Abstract The welding to be performed must be defect free, offer lower residual stress and strain, be compact in size and withstand different load conditions. However, the existing investigations in this scenario are still not modernized. Therefore, in this study, a specific welding method called laser beam welding (LBW) is performed and different weld parameters have been inspected and analysed. Advanced instruments based on the non-destructive (ND) are implemented to find the variable LBW responses such as weld bead defects, residuals and strain. The experimentation has been designed using Design Expert software, response surface methodology (RSM) and Box Behnken design (BBD) and verified by analysis of variance (ANOVA) analysis and FIT statistics. Moreover, a hybrid deep neural network-based Krill Herd optimization (DNN-KHO) is implemented to predict the output parameters like, undercut (µm), overlap (µm), total strain (mm/mm) and residual stress (MPa) during welding. The proposed DNN-KHO was also used to optimize LBW input parameters such as, peak power (W), weld speed (mm/s), gas flow rate (l/min) and beam diameter (µm) simultaneously. Predictions show that the proposed DNN-KHO algorithm outperformed by 21.53%, 45.428% and 41.31% higher in accuracy compared to respective hybrid random forest based grey wolf method (RF-GWO), RF and DNN predictions.
{"title":"Design performance optimization of laser beam welded joints made for vehicle chassis application using deep neural network-based Krill Herd method","authors":"Sanjay S. Surwase, S. Bhosle","doi":"10.1080/09507116.2023.2233889","DOIUrl":"https://doi.org/10.1080/09507116.2023.2233889","url":null,"abstract":"Abstract The welding to be performed must be defect free, offer lower residual stress and strain, be compact in size and withstand different load conditions. However, the existing investigations in this scenario are still not modernized. Therefore, in this study, a specific welding method called laser beam welding (LBW) is performed and different weld parameters have been inspected and analysed. Advanced instruments based on the non-destructive (ND) are implemented to find the variable LBW responses such as weld bead defects, residuals and strain. The experimentation has been designed using Design Expert software, response surface methodology (RSM) and Box Behnken design (BBD) and verified by analysis of variance (ANOVA) analysis and FIT statistics. Moreover, a hybrid deep neural network-based Krill Herd optimization (DNN-KHO) is implemented to predict the output parameters like, undercut (µm), overlap (µm), total strain (mm/mm) and residual stress (MPa) during welding. The proposed DNN-KHO was also used to optimize LBW input parameters such as, peak power (W), weld speed (mm/s), gas flow rate (l/min) and beam diameter (µm) simultaneously. Predictions show that the proposed DNN-KHO algorithm outperformed by 21.53%, 45.428% and 41.31% higher in accuracy compared to respective hybrid random forest based grey wolf method (RF-GWO), RF and DNN predictions.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47838120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.1080/09507116.2023.2236936
Ujjaval Modi, Shuja Ahmed, Akhand Rai
Abstract Friction stir welding (FSW) is a solid-state joining technique where the joint strength is mainly influenced by three process parameters, namely, spindle speed (N), welding speed (V), and plunge force (Fz). The modelling of complex relationships between the process parameters and joint strength requires many experiments, which is a challenging, time-consuming, and non-economical affair. To tackle this problem, computational mathematical models such as deep learning (DL) can be employed to predict the joint strength reliably. In this paper, DL techniques, namely, deep multilayer perceptron (DMLP) and long short-term memory (LSTM) networks have been proposed for such a purpose. The DL networks were first trained with the FSW experimental data and then, the pre-trained models were used for predicting the weld strength. It was found that the DMLP and LSTM models provided lower prediction errors, which are RMSE of 3.30 and 7.63, respectively, and can be effectively utilized for determining weld quality. The proposed DL-based techniques were further compared with the traditional models – the shallow artificial neural network (SANN) model having an RMSE of 27.11 and the ANFIS model having an RMSE of 5.31. DMLP was found to be superior in determining the weld strength most accurately.
{"title":"Prediction of ultimate tensile strength of friction stir welding joint using deep learning-based-multilayer perceptron and long short term memory networks","authors":"Ujjaval Modi, Shuja Ahmed, Akhand Rai","doi":"10.1080/09507116.2023.2236936","DOIUrl":"https://doi.org/10.1080/09507116.2023.2236936","url":null,"abstract":"Abstract Friction stir welding (FSW) is a solid-state joining technique where the joint strength is mainly influenced by three process parameters, namely, spindle speed (N), welding speed (V), and plunge force (Fz). The modelling of complex relationships between the process parameters and joint strength requires many experiments, which is a challenging, time-consuming, and non-economical affair. To tackle this problem, computational mathematical models such as deep learning (DL) can be employed to predict the joint strength reliably. In this paper, DL techniques, namely, deep multilayer perceptron (DMLP) and long short-term memory (LSTM) networks have been proposed for such a purpose. The DL networks were first trained with the FSW experimental data and then, the pre-trained models were used for predicting the weld strength. It was found that the DMLP and LSTM models provided lower prediction errors, which are RMSE of 3.30 and 7.63, respectively, and can be effectively utilized for determining weld quality. The proposed DL-based techniques were further compared with the traditional models – the shallow artificial neural network (SANN) model having an RMSE of 27.11 and the ANFIS model having an RMSE of 5.31. DMLP was found to be superior in determining the weld strength most accurately.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44863590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-02DOI: 10.1080/09507116.2023.2228039
Mami Mihara-Narita, Konosuke Asai, H. Mori, N. Saito, Y. Chino, H. Sato, Yoshimi Watanabe
Abstract Effects of annealing on the interfacial microstructure, mechanical properties, and residual stress of the explosively welded AZ80 magnesium alloy and A6005C aluminium alloy cladding plate were investigated. By explosive welding, a thin interlayer composed by an intermetallic compound, i.e. γ-Mg17Al12 phase, was formed at the interface of the cladding plate. After annealing at both 373 K and 473 K, the thickness of the interlayer increased. After annealing at 473 K, the interlayer changed from a single layer of γ-Mg17Al12 phase to a double layer of γ-Mg17Al12 phase and β-Al3Mg2 phase, resulting in a decrease in shear strength. As a result of nanoindentation measurement at the interface, the hardness was remarkably high in the β-Al3Mg2 phase. It was suggested that this phase became the crack initiation site for brittle fracture and the shear strength is decreased. Measurements of the residual stress using synchrotron radiation X-rays at the interface of cladding plate revealed the tendency of the generation of tensile residual stress on AZ80 magnesium alloy side and compressive residual stress on A6005C aluminium alloy side. After annealing at 473 K, residual stress in AZ80 magnesium alloy side and A6005C aluminium alloy side changed to compressive and tensile stresses, respectively, and these stress values became smaller in both cases. On the other hand, after annealing at 373 K, compressive residual stress was observed in both AZ80 magnesium alloy side and A6005C aluminium alloy side.
摘要 研究了退火对爆炸焊接 AZ80 镁合金和 A6005C 铝合金覆层板界面微观结构、机械性能和残余应力的影响。通过爆炸焊接，在覆层板的界面上形成了由金属间化合物（即γ-Mg17Al12 相）组成的薄夹层。在 373 K 和 473 K 下退火后，夹层厚度均有所增加。在 473 K 退火后，夹层从单层的 γ-Mg17Al12 相变为双层的 γ-Mg17Al12 相和β-Al3Mg2 相，导致剪切强度下降。界面处的纳米压痕测量结果表明，β-Al3Mg2 相的硬度非常高。这表明该相成为脆性断裂的裂纹起始点，剪切强度降低。利用同步辐射 X 射线测量覆层板界面的残余应力，发现 AZ80 镁合金一侧有产生拉伸残余应力的趋势，而 A6005C 铝合金一侧则有产生压缩残余应力的趋势。在 473 K 退火后，AZ80 镁合金侧和 A6005C 铝合金侧的残余应力分别变为压应力和拉应力，并且这些应力值都变小了。另一方面，在 373 K 退火后，在 AZ80 镁合金侧和 A6005C 铝合金侧都观察到了压缩残余应力。
{"title":"Effects of annealing on the interfacial microstructure and mechanical properties of explosively welded AZ80 magnesium alloy and A6005C aluminium alloy","authors":"Mami Mihara-Narita, Konosuke Asai, H. Mori, N. Saito, Y. Chino, H. Sato, Yoshimi Watanabe","doi":"10.1080/09507116.2023.2228039","DOIUrl":"https://doi.org/10.1080/09507116.2023.2228039","url":null,"abstract":"Abstract Effects of annealing on the interfacial microstructure, mechanical properties, and residual stress of the explosively welded AZ80 magnesium alloy and A6005C aluminium alloy cladding plate were investigated. By explosive welding, a thin interlayer composed by an intermetallic compound, i.e. γ-Mg17Al12 phase, was formed at the interface of the cladding plate. After annealing at both 373 K and 473 K, the thickness of the interlayer increased. After annealing at 473 K, the interlayer changed from a single layer of γ-Mg17Al12 phase to a double layer of γ-Mg17Al12 phase and β-Al3Mg2 phase, resulting in a decrease in shear strength. As a result of nanoindentation measurement at the interface, the hardness was remarkably high in the β-Al3Mg2 phase. It was suggested that this phase became the crack initiation site for brittle fracture and the shear strength is decreased. Measurements of the residual stress using synchrotron radiation X-rays at the interface of cladding plate revealed the tendency of the generation of tensile residual stress on AZ80 magnesium alloy side and compressive residual stress on A6005C aluminium alloy side. After annealing at 473 K, residual stress in AZ80 magnesium alloy side and A6005C aluminium alloy side changed to compressive and tensile stresses, respectively, and these stress values became smaller in both cases. On the other hand, after annealing at 373 K, compressive residual stress was observed in both AZ80 magnesium alloy side and A6005C aluminium alloy side.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139364327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to expand the application of high strength steel sheets to automotive bodies, stabilizing nugget diameter of resistance spot welds is required in the presence of several industrial disturbances. This study aims to ensure the nugget diameter of high strength steel sheets regardless weld spacing by utilizing adaptive control technology based on real-time feedback of heat quantity. Short weld spacing leads to expulsion from the sheet surface applying conventional adaptive control welding for mild steel sheets, whereas decrease in nugget diameter due to reduction of effective welding current for high strength steel sheets. On the other hand, two-stage adaptive control method enables to ensure nugget diameter regardless of steel strength even with 10 mm weld spacing, in which heat quantity was controlled independently in each stage of welding. The mechanism of these phenomena was revealed by verifying the influence of physical properties of steel and welding current pattern on the shunting phenomena using numerical simulation.
{"title":"Development of resistance spot welding technology applying multi-stage adaptive control for narrow pitch spot welding of high strength steel sheets","authors":"Chikaumi Sawanishi, Hiroshi Matsuda, Yasuaki Okita, Rinsei Ikeda","doi":"10.1080/09507116.2023.2228036","DOIUrl":"https://doi.org/10.1080/09507116.2023.2228036","url":null,"abstract":"In order to expand the application of high strength steel sheets to automotive bodies, stabilizing nugget diameter of resistance spot welds is required in the presence of several industrial disturbances. This study aims to ensure the nugget diameter of high strength steel sheets regardless weld spacing by utilizing adaptive control technology based on real-time feedback of heat quantity. Short weld spacing leads to expulsion from the sheet surface applying conventional adaptive control welding for mild steel sheets, whereas decrease in nugget diameter due to reduction of effective welding current for high strength steel sheets. On the other hand, two-stage adaptive control method enables to ensure nugget diameter regardless of steel strength even with 10 mm weld spacing, in which heat quantity was controlled independently in each stage of welding. The mechanism of these phenomena was revealed by verifying the influence of physical properties of steel and welding current pattern on the shunting phenomena using numerical simulation.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135260368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-18DOI: 10.1080/09507116.2023.2222485
Yuheng Liu, T. Yasui, Toshiaki Fukuhara, Shuhei Yamaguchi, Katashi Hirosawa, T. Mori
Abstract Dissimilar materials welding between A6061 and SPC270 thin sheets was performed through friction stir lap welding and the effects of welding tool shape and clearance were investigated. The welding process was carried out on the 3-axis vertical machining center without tilt angle, using welding tools with flat or scroll shoulder surfaces. The highest tensile shear strength of 208.2 MPa using the flat shoulder was achieved under tool rotation speed of 2000 rpm and welding speed of 500 mm/min. Groove-like defects were found at the advancing side of this welding joint, which was thought to be caused by the deficiency of plastic material flow. Scroll shoulder improved the plastic material flow of aluminum alloys and weld surface without defects. However, cavities were formed in joints welding with a clearance of 0.1 mm near the interface between A6061 and SPC270. Reduction of clearance suppressed the formation of cavities and tensile shear strength of 217.9 MPa was achieved with the clearance of 0 mm. The welding interface was observed by SEM and TEM for microstructure investigation. Welding interface temperature during FSLW was measured and the factors for welding strength variation were also discussed in this paper.
{"title":"Friction stir lap welding between A6061/SPC270 thin sheets using welding tool with scroll shoulder","authors":"Yuheng Liu, T. Yasui, Toshiaki Fukuhara, Shuhei Yamaguchi, Katashi Hirosawa, T. Mori","doi":"10.1080/09507116.2023.2222485","DOIUrl":"https://doi.org/10.1080/09507116.2023.2222485","url":null,"abstract":"Abstract Dissimilar materials welding between A6061 and SPC270 thin sheets was performed through friction stir lap welding and the effects of welding tool shape and clearance were investigated. The welding process was carried out on the 3-axis vertical machining center without tilt angle, using welding tools with flat or scroll shoulder surfaces. The highest tensile shear strength of 208.2 MPa using the flat shoulder was achieved under tool rotation speed of 2000 rpm and welding speed of 500 mm/min. Groove-like defects were found at the advancing side of this welding joint, which was thought to be caused by the deficiency of plastic material flow. Scroll shoulder improved the plastic material flow of aluminum alloys and weld surface without defects. However, cavities were formed in joints welding with a clearance of 0.1 mm near the interface between A6061 and SPC270. Reduction of clearance suppressed the formation of cavities and tensile shear strength of 217.9 MPa was achieved with the clearance of 0 mm. The welding interface was observed by SEM and TEM for microstructure investigation. Welding interface temperature during FSLW was measured and the factors for welding strength variation were also discussed in this paper.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45938875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractAbstractResistance spot welding is used in automobile body assembly. Tensile shear test is one of the strength evaluation methods for welded joints. Generally, in tensile shear tests of lap joints, rotational deformation occurs in the joint due to offset of the load axis. In this paper, the effect of rotational deformation of resistance spot welded lap joints on tensile shear strength was investigated. A high-strength steel plate HT590 was used. First, tensile shear tests were conducted using only resistance spot welding (Normal) and a specimen in which the welded joint part was sandwiched between two steel blocks to suppress rotational deformation. For the specimens sandwiched between steel blocks, a specimen was prepared with a constrained point parallel (P) to the tensile direction and a specimen with a constrained point vertical (V) to the tensile direction. And the length of the steel blocks was varied in five ways for the tensile shear test. The results showed that the tensile shear strength increased as the length of the steel block increased. However, the suppression of rotational deformation didn’t have a significant effect on tensile shear strength. In tensile shear tests of lap joints, opening of the lap plates occurs in addition to rotational deformation. Therefore, tensile shear tests were conducted using a specimen with two steel blocks sandwiched at the edge of the lap to suppress the opening of the plates. The experiment was reproduced and investigated by FEM analysis. The results showed that the tensile shear strength increased in the deformation-suppressed specimens compared to Normal specimens. In other words, it is clear that the suppression of plate opening has an effect on the increase in tensile shear strength. The above results indicate that suppression of plate opening is effective in increasing tensile shear strength.Keywords: Resistance spot weldinghigh tensile strength steeltensile shear strengthrotational deformationopening of the platesFEM analysistensile shear test
{"title":"Effect of plate deformation around the nugget during tensile test on tensile shear strength of resistance spot welded lap joints","authors":"Takanori Kitamura, Tetsuya Akiyama, Mitsuhiro Imamura, Tomoya Kawabata, Atsuro Uemura, Chinatsu Mihara, Koki Iwatani","doi":"10.1080/09507116.2023.2222958","DOIUrl":"https://doi.org/10.1080/09507116.2023.2222958","url":null,"abstract":"AbstractAbstractResistance spot welding is used in automobile body assembly. Tensile shear test is one of the strength evaluation methods for welded joints. Generally, in tensile shear tests of lap joints, rotational deformation occurs in the joint due to offset of the load axis. In this paper, the effect of rotational deformation of resistance spot welded lap joints on tensile shear strength was investigated. A high-strength steel plate HT590 was used. First, tensile shear tests were conducted using only resistance spot welding (Normal) and a specimen in which the welded joint part was sandwiched between two steel blocks to suppress rotational deformation. For the specimens sandwiched between steel blocks, a specimen was prepared with a constrained point parallel (P) to the tensile direction and a specimen with a constrained point vertical (V) to the tensile direction. And the length of the steel blocks was varied in five ways for the tensile shear test. The results showed that the tensile shear strength increased as the length of the steel block increased. However, the suppression of rotational deformation didn’t have a significant effect on tensile shear strength. In tensile shear tests of lap joints, opening of the lap plates occurs in addition to rotational deformation. Therefore, tensile shear tests were conducted using a specimen with two steel blocks sandwiched at the edge of the lap to suppress the opening of the plates. The experiment was reproduced and investigated by FEM analysis. The results showed that the tensile shear strength increased in the deformation-suppressed specimens compared to Normal specimens. In other words, it is clear that the suppression of plate opening has an effect on the increase in tensile shear strength. The above results indicate that suppression of plate opening is effective in increasing tensile shear strength.Keywords: Resistance spot weldinghigh tensile strength steeltensile shear strengthrotational deformationopening of the platesFEM analysistensile shear test","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134891861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-03DOI: 10.1080/09507116.2023.2224929
K. Anbalagan, S. Ramasubramanian, Charles David, S. Manivannan, A. Kannan, D. Mohan
Abstract Welding and joining Titanium and its alloys are always challenging because getting a contamination-free joint is difficult with arc welding. For this concern, an attempt was made with and without shielding arrangements using the Gas Tungsten Arc Welding (GTAW) process on the Ti-6Al-4V alloy sheet. To study the presence of oxygen and other elements with respect to surface colourization at the weld zone, an Energy-dispersive X-ray spectroscopy (EDX) analysis is carried out. Based on the EDX analysis, post-flow and pre-flow shielding gases are also included in the operation window. Bead on Plate (BoP) trials are performed using the shielding arrangement setup and selected parameters on the thin sheets (2 mm) of Ti-6Al-4V. After examining the BoP trails, defect-free joins in a 2 mm sheet are fabricated using the optimal welding parameters. The microstructure of the joint is captured and compared with the simulation work. Compared to the base metal, coarse and enormous grains are identified at the weld zone. Due to the proper shielding, no cracks appeared in the joint subjected to the three-point bend test. The considerable heat input during the GTAW process resulted in the nucleation of (ά) in FZ, as spotted in the TEM images. The microhardness value at FZ for base metal is 373 HV and 332 HV, respectively. It is confirmed that the suggested shielding setup could prevent contamination in welds resulting in better mechanical properties.
{"title":"Importance of shielding and mechanical characterization of GTAW on Ti-6AL-4V alloy sheet","authors":"K. Anbalagan, S. Ramasubramanian, Charles David, S. Manivannan, A. Kannan, D. Mohan","doi":"10.1080/09507116.2023.2224929","DOIUrl":"https://doi.org/10.1080/09507116.2023.2224929","url":null,"abstract":"Abstract Welding and joining Titanium and its alloys are always challenging because getting a contamination-free joint is difficult with arc welding. For this concern, an attempt was made with and without shielding arrangements using the Gas Tungsten Arc Welding (GTAW) process on the Ti-6Al-4V alloy sheet. To study the presence of oxygen and other elements with respect to surface colourization at the weld zone, an Energy-dispersive X-ray spectroscopy (EDX) analysis is carried out. Based on the EDX analysis, post-flow and pre-flow shielding gases are also included in the operation window. Bead on Plate (BoP) trials are performed using the shielding arrangement setup and selected parameters on the thin sheets (2 mm) of Ti-6Al-4V. After examining the BoP trails, defect-free joins in a 2 mm sheet are fabricated using the optimal welding parameters. The microstructure of the joint is captured and compared with the simulation work. Compared to the base metal, coarse and enormous grains are identified at the weld zone. Due to the proper shielding, no cracks appeared in the joint subjected to the three-point bend test. The considerable heat input during the GTAW process resulted in the nucleation of (ά) in FZ, as spotted in the TEM images. The microhardness value at FZ for base metal is 373 HV and 332 HV, respectively. It is confirmed that the suggested shielding setup could prevent contamination in welds resulting in better mechanical properties.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45931432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-03DOI: 10.1080/09507116.2023.2222550
Z. Dong, Yiwen Li, J. Miu, Z. Liu, Chen-Hsuan Chang, Yunlong Chang
Abstract Based on the principle of LC resonance, high-frequency sine wave pulse DC TIG welding (HFSWP DC TIG) was developed, and welding experiments were conducted on AISI444 ferritic stainless steel (FSS). The arc characteristics of HFSWP DC TIG and its effect on weld appearance and microstructure were studied theoretically and experimentally. The experimental results show that under the same conditions, compared with constant-current DC conventional arc welding (CAW), the arc pressure and arc thermal efficiency of HFSWP DC TIG are improved, and the weld penetration of the weld is increased by nearly two times. The weld microstructure is single-phase ferrite, and carbonitride, Laves phase, and phase are formed in the joint. In addition, according to the theoretical calculation of the pulse current waveform, the reason why the arc pressure of the high-frequency sine wave pulse current is increased compared with the constant-current DC and high-frequency square wave (triangular wave) pulse current is explained. The mechanism of arc shape and weld appearance change is described from the microscopic point of view, and the reason for the appearance of equiaxed grain in the weld is analyzed. HFSWP DC TIG provides a new idea for the improvement of high-frequency pulse technology.
基于LC谐振原理，研制了高频正弦波脉冲直流TIG焊(HFSWP DC TIG)，并在AISI444铁素体不锈钢(FSS)上进行了焊接实验。从理论上和实验上研究了HFSWP直流TIG的电弧特性及其对焊缝形貌和显微组织的影响。实验结果表明，在相同条件下，与恒流直流常规电弧焊(CAW)相比，HFSWP直流TIG的电弧压力和电弧热效率都有所提高，焊缝的熔深提高了近两倍。焊缝组织为单相铁素体，在接头中形成碳氮化物、Laves相和Laves相。此外，根据脉冲电流波形的理论计算，解释了高频正弦波脉冲电流相对于恒流直流电和高频方波(三角波)脉冲电流弧压增大的原因。从微观角度阐述了电弧形状和焊缝形貌变化的机理，分析了焊缝中出现等轴晶粒的原因。HFSWP直流TIG为高频脉冲技术的改进提供了新的思路。
{"title":"Study on arc characteristics under high-frequency sine wave pulse current and effect of weld appearance and microstructure of AISI444 ferritic stainless steel","authors":"Z. Dong, Yiwen Li, J. Miu, Z. Liu, Chen-Hsuan Chang, Yunlong Chang","doi":"10.1080/09507116.2023.2222550","DOIUrl":"https://doi.org/10.1080/09507116.2023.2222550","url":null,"abstract":"Abstract Based on the principle of LC resonance, high-frequency sine wave pulse DC TIG welding (HFSWP DC TIG) was developed, and welding experiments were conducted on AISI444 ferritic stainless steel (FSS). The arc characteristics of HFSWP DC TIG and its effect on weld appearance and microstructure were studied theoretically and experimentally. The experimental results show that under the same conditions, compared with constant-current DC conventional arc welding (CAW), the arc pressure and arc thermal efficiency of HFSWP DC TIG are improved, and the weld penetration of the weld is increased by nearly two times. The weld microstructure is single-phase ferrite, and carbonitride, Laves phase, and phase are formed in the joint. In addition, according to the theoretical calculation of the pulse current waveform, the reason why the arc pressure of the high-frequency sine wave pulse current is increased compared with the constant-current DC and high-frequency square wave (triangular wave) pulse current is explained. The mechanism of arc shape and weld appearance change is described from the microscopic point of view, and the reason for the appearance of equiaxed grain in the weld is analyzed. HFSWP DC TIG provides a new idea for the improvement of high-frequency pulse technology.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43798694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-03DOI: 10.1080/09507116.2023.2233887
Xiaohui Han, Zhibin Yang, Yin Ma, Zhendong Mao, G. Ma
Abstract 6A01-T5 aluminum alloy extrusions with a thickness of 4.5 mm were welded by laser-MIG hybrid welding, and the effects of gap width on the microstructure and properties were studied in details. The results indicated that the priorities of the welding parameters on the tensile strength of joints were laser power, defocusing amount and arc current when the welding speed was constant. The gap tolerance of the optimal welding parameters could reach up to 1.1 mm. The morphology and size of the microstructures were similar when the gap width was no larger than 1.1 mm. The grain boundaries became obvious and even cracks appeared near the fusion line when the gap width increased to 1.5 mm. The microhardness distributions almost the same with the different gap widths: highest in the base materials zone, secondly in the heat-affected zone, then in the weld zone, and lowest near the fusion line. The microhardness values reduced in each zone except base materials when the gap width increased to 1.5 mm. The tensile strength reduced as the gap width increased, the specimens all fractured near the fusion line due to where had the lowest microhardness and the fracture showed ductile failure mode.
{"title":"Laser-MIG hybrid welding of aluminium alloy extrusions for high-speed trains: effects of gap width on microstructure and properties","authors":"Xiaohui Han, Zhibin Yang, Yin Ma, Zhendong Mao, G. Ma","doi":"10.1080/09507116.2023.2233887","DOIUrl":"https://doi.org/10.1080/09507116.2023.2233887","url":null,"abstract":"Abstract 6A01-T5 aluminum alloy extrusions with a thickness of 4.5 mm were welded by laser-MIG hybrid welding, and the effects of gap width on the microstructure and properties were studied in details. The results indicated that the priorities of the welding parameters on the tensile strength of joints were laser power, defocusing amount and arc current when the welding speed was constant. The gap tolerance of the optimal welding parameters could reach up to 1.1 mm. The morphology and size of the microstructures were similar when the gap width was no larger than 1.1 mm. The grain boundaries became obvious and even cracks appeared near the fusion line when the gap width increased to 1.5 mm. The microhardness distributions almost the same with the different gap widths: highest in the base materials zone, secondly in the heat-affected zone, then in the weld zone, and lowest near the fusion line. The microhardness values reduced in each zone except base materials when the gap width increased to 1.5 mm. The tensile strength reduced as the gap width increased, the specimens all fractured near the fusion line due to where had the lowest microhardness and the fracture showed ductile failure mode.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48470528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-26DOI: 10.1080/09507116.2023.2203965
Yukihide Yoshihara, N. Osawa, H. Murakawa, Taiyou Kagase
Abstract It is difficult to examine the relation between the root notch welding residual stress (WRS) and the root-failure fatigue strength because of the difficulty in the direct root WRS measurement. The root WRS can be calculated by thermal elastic-plastic finite element analysis (TEPFEA), but its accuracy has not been fully verified yet. In this study, root-failure fatigue tests, in which direct root WRS measurement can be performed, are carried out. Plug welded (PW) specimens with backing plates are used in those tests, and the root WRS in as-welded (AW) and stress-relieved (SR = PWHT) specimens are measured using X-ray diffraction (XRD) method by cutting off the backing plate. The measured WRSs are compared with those calculated by TEPFEA. It is found that the root WRSs in the PW specimens estimated by TEPFEA become much larger than those measured when creep strain is neglected. The SR specimen’s fatigue strength improvement ratio is estimated by using the mean stress effect formulas developed for toe-failure cases (IIW Fatigue Recommendations and MIL-HDBK-5D). The estimated improvement ratio shows fair agreement with that measured.
{"title":"Study on the relationship between the root welding residual stress and the root-failure fatigue strength of Plug Welded specimens","authors":"Yukihide Yoshihara, N. Osawa, H. Murakawa, Taiyou Kagase","doi":"10.1080/09507116.2023.2203965","DOIUrl":"https://doi.org/10.1080/09507116.2023.2203965","url":null,"abstract":"Abstract It is difficult to examine the relation between the root notch welding residual stress (WRS) and the root-failure fatigue strength because of the difficulty in the direct root WRS measurement. The root WRS can be calculated by thermal elastic-plastic finite element analysis (TEPFEA), but its accuracy has not been fully verified yet. In this study, root-failure fatigue tests, in which direct root WRS measurement can be performed, are carried out. Plug welded (PW) specimens with backing plates are used in those tests, and the root WRS in as-welded (AW) and stress-relieved (SR = PWHT) specimens are measured using X-ray diffraction (XRD) method by cutting off the backing plate. The measured WRSs are compared with those calculated by TEPFEA. It is found that the root WRSs in the PW specimens estimated by TEPFEA become much larger than those measured when creep strain is neglected. The SR specimen’s fatigue strength improvement ratio is estimated by using the mean stress effect formulas developed for toe-failure cases (IIW Fatigue Recommendations and MIL-HDBK-5D). The estimated improvement ratio shows fair agreement with that measured.","PeriodicalId":23605,"journal":{"name":"Welding International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44109088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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