In this article, selected studies are reviewed with a focus on the analysis of microstructure development in steel weld metals. In the study of austenitic stainless steel weld metals, microstructure development in the primary ferrite solidification mode (FA mode) was clarified and related to why FAmode welds are resistant to hot cracking. In studies of duplex stainless steel weld metals and high-Cr ferritic stainless steel weld metals, nitrogen-driven microstructure development and TiN-assisted grain refinement, respectively, were described, and discussions about the mechanism of equiaxed grain formation in the weld metals were added in the latter. In the study of low-alloy steel weld metals, the roles of titanium oxide and titanium nitride (TiN) inclusions on intragranular ferrite formation and the refinement of weld microstructure were described based on crystallographic analysis and the first principles calculation. At the end, the potential importance of the application of different multiscale, multiphysics simulations to welding research was pointed out.
{"title":"Understanding and Controlling the Weld Microstructure of Steels","authors":"TOSHIHIKO KOSEKI","doi":"10.29391/2023.102.018","DOIUrl":"https://doi.org/10.29391/2023.102.018","url":null,"abstract":"In this article, selected studies are reviewed with a focus on the analysis of microstructure development in steel weld metals. In the study of austenitic stainless steel weld metals, microstructure development in the primary ferrite solidification mode (FA mode) was clarified and related to why FAmode welds are resistant to hot cracking. In studies of duplex stainless steel weld metals and high-Cr ferritic stainless steel weld metals, nitrogen-driven microstructure development and TiN-assisted grain refinement, respectively, were described, and discussions about the mechanism of equiaxed grain formation in the weld metals were added in the latter. In the study of low-alloy steel weld metals, the roles of titanium oxide and titanium nitride (TiN) inclusions on intragranular ferrite formation and the refinement of weld microstructure were described based on crystallographic analysis and the first principles calculation. At the end, the potential importance of the application of different multiscale, multiphysics simulations to welding research was pointed out.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135707137","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}
TAE HYUN LEE, DONG HYUCK KAM, CHEOLHEE KIM, JE HOON OH
In arc welding and wire arc additive manufacturing (WAAM) of Ti alloys, pulsed gas metal arc (GMA) processes have a higher deposition than shortcircuiting GMA mode processes, such as cold metal transfer, surface tension transfer, and controlled short-circuit processes. In this study, pulsed GMA WAAM of Ti–6Al–4V alloy was conducted under Ar, Ar50%/He50% mixed, and He shielding gases. Owing to the thermionic emission of electrons from the Ti substrate, cathode jets were emitted from the high-temperature region of the weld pool, which interfered with droplet transfer into the weld pool. The arc shape surrounding the droplet varied according to the shielding gas, and the arc was established at the bottom of the hanging droplet under the He shielding gas, which disturbed droplet detachment. Two spatter generation modes of droplet ejection from the weld pool surface and inflight droplet repelling were observed, and droplet ejection was the most frequent spatter generation mechanism. The mixed shielding gas showed the best performance in terms of arc stability, wire melting, droplet transfer, and spatter suppression. The arc, cathode, and metal transfer characteristics were elucidated in this study, and a suitable gas composition for pulsed GMA WAAM of Ti alloys was proposed.
{"title":"Observation of Arc and Metal Transfer Behavior according to Shielding Gas in the WAAM of Ti–6Al–4V Alloy Using the Pulsed Gas Metal Arc Process","authors":"TAE HYUN LEE, DONG HYUCK KAM, CHEOLHEE KIM, JE HOON OH","doi":"10.29391/2023.102.020","DOIUrl":"https://doi.org/10.29391/2023.102.020","url":null,"abstract":"In arc welding and wire arc additive manufacturing (WAAM) of Ti alloys, pulsed gas metal arc (GMA) processes have a higher deposition than shortcircuiting GMA mode processes, such as cold metal transfer, surface tension transfer, and controlled short-circuit processes. In this study, pulsed GMA WAAM of Ti–6Al–4V alloy was conducted under Ar, Ar50%/He50% mixed, and He shielding gases. Owing to the thermionic emission of electrons from the Ti substrate, cathode jets were emitted from the high-temperature region of the weld pool, which interfered with droplet transfer into the weld pool. The arc shape surrounding the droplet varied according to the shielding gas, and the arc was established at the bottom of the hanging droplet under the He shielding gas, which disturbed droplet detachment. Two spatter generation modes of droplet ejection from the weld pool surface and inflight droplet repelling were observed, and droplet ejection was the most frequent spatter generation mechanism. The mixed shielding gas showed the best performance in terms of arc stability, wire melting, droplet transfer, and spatter suppression. The arc, cathode, and metal transfer characteristics were elucidated in this study, and a suitable gas composition for pulsed GMA WAAM of Ti alloys was proposed.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135707139","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}
Measuring and controlling the power density distribution of electron beams used for welding is critical for producing repeatable welds and for transferring welding parameters between different machines. On any given machine, the power density distribution is controlled by defocusing the beam relative to its sharpest focused condition. However, measuring the power density distribution can be difficult due to the intense nature of welding beams and is further complicated by imperfect electron optics that can distort the beam, making it difficult to quantify. The enhanced modified Faraday cup (EMFC) diagnostic method was used here for beam analysis that utilizes computed tomography to reconstruct the beam’s power density distribution. These results were compared to the International Standards Organization (ISO) method for characterizing laser beams using a second-moment D4σ calculation. For ideal Gaussian-shaped beams, both methods would give the same result. However, for imperfect beams, the calculated D4σ diameter was shown to be about 25% larger relative to the FWe2 diameter measured by the EMFC due to the heavier weighting of data in the tails of the beam by D4σ. Although both methods produce repeatable welds, it is important to understand the differences in the reported beam diameters, divergence angles, and beam parameter products when transferring parameters between machines.
{"title":"Power Density Distributions in Electron Beams","authors":"JOHN W. ELMER, ALAN T. TERUYA, GORDON GIBBS","doi":"10.29391/2023.102.019","DOIUrl":"https://doi.org/10.29391/2023.102.019","url":null,"abstract":"Measuring and controlling the power density distribution of electron beams used for welding is critical for producing repeatable welds and for transferring welding parameters between different machines. On any given machine, the power density distribution is controlled by defocusing the beam relative to its sharpest focused condition. However, measuring the power density distribution can be difficult due to the intense nature of welding beams and is further complicated by imperfect electron optics that can distort the beam, making it difficult to quantify. The enhanced modified Faraday cup (EMFC) diagnostic method was used here for beam analysis that utilizes computed tomography to reconstruct the beam’s power density distribution. These results were compared to the International Standards Organization (ISO) method for characterizing laser beams using a second-moment D4σ calculation. For ideal Gaussian-shaped beams, both methods would give the same result. However, for imperfect beams, the calculated D4σ diameter was shown to be about 25% larger relative to the FWe2 diameter measured by the EMFC due to the heavier weighting of data in the tails of the beam by D4σ. Although both methods produce repeatable welds, it is important to understand the differences in the reported beam diameters, divergence angles, and beam parameter products when transferring parameters between machines.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135707136","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}
This study addresses the limitations of cross weld tensile testing (CWTT) in quantifying local mechanical properties across microstructural and compositional gradients in dissimilar– and matching–filler metal welds. A digital image correlation (DIC) methodology was validated for application in CWTT by direct comparison of stress-strain curves generated using conventional and virtual DIC extensometers in tensile testing of homogeneous steel samples. DIC-instrumented CWTT of dissimilar weld metal Alloy 625 filler metal on F65 steel demonstrated capability in quantifying the local yield strength, strain-hardening kinetics, and strain at failure in the base metal, heat-affected zone (HAZ), fusion boundary (FB) region, and weld metal in dissimilar and matching filler metal welds. It was shown that the high strain-hardening capacity in Alloy 625 weld metal led to base metal failure in CWTT despite the lower Alloy 625 weld metal yield strength. It was also shown that DIC-instrumented CWTT can be used for determining weld metal undermatching and overmatching conditions in compositionally matching- and dissimilar-metal welds. Furthermore, by quantifying local strain distribution (both elastic and plastic) in the HAZ, FB region, and weld metal, DIC-instrumented CWTT provides an additional method for evaluating hydrogen-assisted cracking susceptibility in dissimilar-metal welds.
{"title":"Application of Digital Image Correlation in Cross Weld Tensile Testing: Test Method Validation","authors":"WILLIAM SIEFERT, BOIAN ALEXANDROV, MIKE BUEHNER","doi":"10.29391/2023.102.015","DOIUrl":"https://doi.org/10.29391/2023.102.015","url":null,"abstract":"This study addresses the limitations of cross weld tensile testing (CWTT) in quantifying local mechanical properties across microstructural and compositional gradients in dissimilar– and matching–filler metal welds. A digital image correlation (DIC) methodology was validated for application in CWTT by direct comparison of stress-strain curves generated using conventional and virtual DIC extensometers in tensile testing of homogeneous steel samples. DIC-instrumented CWTT of dissimilar weld metal Alloy 625 filler metal on F65 steel demonstrated capability in quantifying the local yield strength, strain-hardening kinetics, and strain at failure in the base metal, heat-affected zone (HAZ), fusion boundary (FB) region, and weld metal in dissimilar and matching filler metal welds. It was shown that the high strain-hardening capacity in Alloy 625 weld metal led to base metal failure in CWTT despite the lower Alloy 625 weld metal yield strength. It was also shown that DIC-instrumented CWTT can be used for determining weld metal undermatching and overmatching conditions in compositionally matching- and dissimilar-metal welds. Furthermore, by quantifying local strain distribution (both elastic and plastic) in the HAZ, FB region, and weld metal, DIC-instrumented CWTT provides an additional method for evaluating hydrogen-assisted cracking susceptibility in dissimilar-metal welds.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135691197","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}
HO KWON, UMAIR SHAH, XUN LIU, JULIO MALPICA, PATRICK LESTER, HARINI BONAM
A recently developed hybrid joining process known as ultrasonic resistance spot welding (URW) was used on various pairs of similar and dissimilar aluminum (Al) alloys with different thicknesses, including AA5182–AA5182, AA6111–AA6111, AA7075–AA6111, and AA7075–AA5182, and comprehensively studied. Compared to conventional resistance spot welding (RSW), URW of the alloys showed consistently enhanced mechanical behavior in lap shear and crosstension tests. This can be attributed to the multiple perspectives on microstructure improvements. For different stacks of Al alloys and welding conditions, nugget formation was promoted with a larger nugget size in URW. In the nugget center, ultrasonically assisted (UA) vibration facilitated the formation of an equiaxed crystal zone. At the nugget boundary, URW showed a narrower coarse columnar zone and partially melted zone, which are associatedwith the lowest hardness in the weld. Specifically in dissimilar Al welds, UA vibration moved the nugget more centered toward the weld interface. These microstructure improvements indicated UA vibration can homogenize temperature and elemental distribution, which modifies solidification behavior.
{"title":"Experimental Analysis on Ultrasonic Resistance Spot Welding of Aluminum Alloys","authors":"HO KWON, UMAIR SHAH, XUN LIU, JULIO MALPICA, PATRICK LESTER, HARINI BONAM","doi":"10.29391/2023.102.017","DOIUrl":"https://doi.org/10.29391/2023.102.017","url":null,"abstract":"A recently developed hybrid joining process known as ultrasonic resistance spot welding (URW) was used on various pairs of similar and dissimilar aluminum (Al) alloys with different thicknesses, including AA5182–AA5182, AA6111–AA6111, AA7075–AA6111, and AA7075–AA5182, and comprehensively studied. Compared to conventional resistance spot welding (RSW), URW of the alloys showed consistently enhanced mechanical behavior in lap shear and crosstension tests. This can be attributed to the multiple perspectives on microstructure improvements. For different stacks of Al alloys and welding conditions, nugget formation was promoted with a larger nugget size in URW. In the nugget center, ultrasonically assisted (UA) vibration facilitated the formation of an equiaxed crystal zone. At the nugget boundary, URW showed a narrower coarse columnar zone and partially melted zone, which are associatedwith the lowest hardness in the weld. Specifically in dissimilar Al welds, UA vibration moved the nugget more centered toward the weld interface. These microstructure improvements indicated UA vibration can homogenize temperature and elemental distribution, which modifies solidification behavior.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135691198","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
A C-type filler metal was developed to overcome the low deposition rate (DR) of gas tungsten arc welding (GTAW). The present study investigated the maximum DR for a novel C-type filler metal and compared it to conventional circular welding wires during GTAW using an Alloy 625 filler metal. For comparison with conventional circular welding wires, a ø1.2-mm (0.047-in.) welding wire, which is most widely used in practice, and a ø2.4-mm (0.094-in.) welding wire, which has almost the same sectional area as the novel C-type filler metal, were used in this research. An industrial robot was utilized to produce bead-on-plate welds in the flat position. The results revealed that at the same 200-A welding current, the DR of the C-type filler metal was higher than the conventional circular welding wires by 1.17 to 1.4 times according to the sectional area of the circular welding wires. At a high welding current of 500 A, it was impossible for the ø1.2-mm welding wire to deposit quality welds, and the acceptable range of the DR for the ø2.4-mm welding wire was narrow (i.e., 7–8 kg/h [15.4–17.6 lb/h]). However, the acceptable range of the DR for the C-type filler metal was as broad as 5.04–12.1 kg/h (11.1–26.6 lb/h) under the high welding current of 500 A. The maximum DR of the C-type filler metal was 1.51 times that of the ø2.4-mm welding wire. The mechanism of obtaining a high DR using the C-type filler metal was analyzed from the viewpoint of the continuous bridging transfer at the melting edge of the C-type filler metal. The ability of the C-type filler metal to achieve high DRs at high-current regions was superior to the conventional ø1.2- and ø2.4-mm welding wires.
针对钨极气体保护焊(GTAW)中沉积速率低的问题，研制了一种c型填充金属。本文研究了一种新型c型填充金属在GTAW中的最大DR，并将其与使用Alloy 625填充金属的传统圆形焊丝进行了比较。为了与传统的圆形焊丝进行比较，本研究采用了在实践中使用最广泛的ø1.2 mm (0.047-in.)焊丝和与新型c型填充金属具有几乎相同截面积的ø2.4 mm (0.094-in.)焊丝。利用工业机器人在平面位置进行了焊头焊接。结果表明，在相同的200a焊接电流下，按圆形焊丝的截面积计算，c型钎料的DR比常规圆形焊丝高1.17 ~ 1.4倍。在500a的高焊接电流下，ø1.2 mm焊丝不可能焊出高质量的焊缝，而ø2.4 mm焊丝的DR可接受范围较窄(即7-8 kg/h [15.4-17.6 lb/h])。然而，在500a的高焊接电流下，c型填充金属的可接受DR范围为5.04-12.1 kg/h (11.1-26.6 lb/h)。c型钎料的最大DR为ø2.4 mm焊丝的1.51倍。从c型钎料熔点边缘连续桥接转移的角度分析了c型钎料获得高DR的机理。c型填充金属在大电流区域获得高dr的能力优于传统的ø1.2和ø2.4 mm焊丝。
{"title":"Melting Characteristics of C-Type Filler Metal in GTAW","authors":"MURALIMOHAN CHEEPU, HYO JIN BAEK, YOUNG SIK KIM, SANG MYUNG CHO","doi":"10.29391/2023.102.016","DOIUrl":"https://doi.org/10.29391/2023.102.016","url":null,"abstract":"A C-type filler metal was developed to overcome the low deposition rate (DR) of gas tungsten arc welding (GTAW). The present study investigated the maximum DR for a novel C-type filler metal and compared it to conventional circular welding wires during GTAW using an Alloy 625 filler metal. For comparison with conventional circular welding wires, a ø1.2-mm (0.047-in.) welding wire, which is most widely used in practice, and a ø2.4-mm (0.094-in.) welding wire, which has almost the same sectional area as the novel C-type filler metal, were used in this research. An industrial robot was utilized to produce bead-on-plate welds in the flat position. The results revealed that at the same 200-A welding current, the DR of the C-type filler metal was higher than the conventional circular welding wires by 1.17 to 1.4 times according to the sectional area of the circular welding wires. At a high welding current of 500 A, it was impossible for the ø1.2-mm welding wire to deposit quality welds, and the acceptable range of the DR for the ø2.4-mm welding wire was narrow (i.e., 7–8 kg/h [15.4–17.6 lb/h]). However, the acceptable range of the DR for the C-type filler metal was as broad as 5.04–12.1 kg/h (11.1–26.6 lb/h) under the high welding current of 500 A. The maximum DR of the C-type filler metal was 1.51 times that of the ø2.4-mm welding wire. The mechanism of obtaining a high DR using the C-type filler metal was analyzed from the viewpoint of the continuous bridging transfer at the melting edge of the C-type filler metal. The ability of the C-type filler metal to achieve high DRs at high-current regions was superior to the conventional ø1.2- and ø2.4-mm welding wires.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135894963","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}
SONGYU WANG, JI CHEN, CHUNYANG XIA, CHUANSONG WU, WENBIN ZHANG, RUIDONG LI
To improve the level of welding automation in the industry, there are increasing requirements for highly intelligent and accurate inspections of the welding process in real time. This paper proposed a new method for predicting weld dimensions based on binocular imaging information and a deep learning system. The binocular imaging information was acquired by binocular vision equipment and an image processing algorithm. A convolutional neural network structure was developed by adding a fully connected block and loss function judgment. A new calculating procedure was proposed to extract and link the information of the processed weld pool image and the weld parameters effectively. With the help of 7394 training samples, the results of 1849 testing samples showed that the overall accuracy of the proposed model was higher than 93% for the prediction of weld dimensions, which could meet the requirements in practical applications.
{"title":"Weld Geometry Prediction Based on Binocular Vision and Deep Learning","authors":"SONGYU WANG, JI CHEN, CHUNYANG XIA, CHUANSONG WU, WENBIN ZHANG, RUIDONG LI","doi":"10.29391/2023.102.014","DOIUrl":"https://doi.org/10.29391/2023.102.014","url":null,"abstract":"To improve the level of welding automation in the industry, there are increasing requirements for highly intelligent and accurate inspections of the welding process in real time. This paper proposed a new method for predicting weld dimensions based on binocular imaging information and a deep learning system. The binocular imaging information was acquired by binocular vision equipment and an image processing algorithm. A convolutional neural network structure was developed by adding a fully connected block and loss function judgment. A new calculating procedure was proposed to extract and link the information of the processed weld pool image and the weld parameters effectively. With the help of 7394 training samples, the results of 1849 testing samples showed that the overall accuracy of the proposed model was higher than 93% for the prediction of weld dimensions, which could meet the requirements in practical applications.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135052775","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}
Alejandro HINTZE CESARO, G. Lehnhoff, Eric Willett
This work confirmed that the locations of minimum and maximum HAZ hardness occurred within the FGHAZ and CGHAZ zones. CGHAZ and FGHAZ hardness data from different SMAW passes were compared to determine their correlation.
{"title":"Correlation between the Coarse- and Fine-Grained HAZ Hardness of X70 Pipeline SMA Welded Girth Welds","authors":"Alejandro HINTZE CESARO, G. Lehnhoff, Eric Willett","doi":"10.29391/2023.102.012","DOIUrl":"https://doi.org/10.29391/2023.102.012","url":null,"abstract":"This work confirmed that the locations of minimum and maximum HAZ hardness occurred within the FGHAZ and CGHAZ zones. CGHAZ and FGHAZ hardness data from different SMAW passes were compared to determine their correlation.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46223032","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}
TC4 titanium alloy (TC4) was vacuum diffusion welded to T2 copper (T2) with vanadium (V) foil as an interlayer. The influence of process parameters on elemental diffusion behavior, microstructure evolution, and shear performance of welded joints was explored. An obvious solid-solution diffusion zone appeared in the welded interface between TC4 and V, but no distinct diffusion zone formed in the joint interface of V/T2. The solid-solution phases of (Ti6, V)ss, (Ti3, V)ss, and (Ti, V7)ss appeared in the interface of TC4/V. The crystallographic orientations of (Ti6, V)ss, (Ti3, V)ss, and (Ti, V7)ss phases in high-resolution transmission electron microscope images were (002), (201), and (121), respectively. The lattice mismatch between (Ti6, V)ss and (Ti3, V)ss was calculated to be 11.9%. The activation energy to form a stable solid solution between titanium and vanadium was 226.6 kJ/mol. The highest shear strength of the welded joint reached 160 MPa, obtained at 860°C (1580°F) for 60 min. The joint fractured along the interface of V/T2, illustrating that the solid-solution structure between Ti and V was stronger than the metallurgical bonding between V and Cu. The fracture surface of the welded joints revealed a river pattern and ladder topography, representing a cleavage fracture mode. FCC-Cu, BCC-V, and β-Ti were detected on both fracture surfaces of the TC4 titanium alloy and T2 pure copper sides. The influence of welding temperature on the diffusion of V in Ti was greater than on Ti in V, and Ti and Cu diffused faster than V in the joint.
{"title":"Diffusion Welding for TC4 Titanium Alloy/T2 Copper with Vanadium Foil","authors":"Baosheng Wu, Honggang Dong, Yu-E. Ma, Peng Li, C. Li, Libing Huang, Liangliang Zhang","doi":"10.29391/2023.102.011","DOIUrl":"https://doi.org/10.29391/2023.102.011","url":null,"abstract":"TC4 titanium alloy (TC4) was vacuum diffusion welded to T2 copper (T2) with vanadium (V) foil as an interlayer. The influence of process parameters on elemental diffusion behavior, microstructure evolution, and shear performance of welded joints was explored. An obvious solid-solution diffusion zone appeared in the welded interface between TC4 and V, but no distinct diffusion zone formed in the joint interface of V/T2. The solid-solution phases of (Ti6, V)ss, (Ti3, V)ss, and (Ti, V7)ss appeared in the interface of TC4/V. The crystallographic orientations of (Ti6, V)ss, (Ti3, V)ss, and (Ti, V7)ss phases in high-resolution transmission electron microscope images were (002), (201), and (121), respectively. The lattice mismatch between (Ti6, V)ss and (Ti3, V)ss was calculated to be 11.9%. The activation energy to form a stable solid solution between titanium and vanadium was 226.6 kJ/mol. The highest shear strength of the welded joint reached 160 MPa, obtained at 860°C (1580°F) for 60 min. The joint fractured along the interface of V/T2, illustrating that the solid-solution structure between Ti and V was stronger than the metallurgical bonding between V and Cu. The fracture surface of the welded joints revealed a river pattern and ladder topography, representing a cleavage fracture mode. FCC-Cu, BCC-V, and β-Ti were detected on both fracture surfaces of the TC4 titanium alloy and T2 pure copper sides. The influence of welding temperature on the diffusion of V in Ti was greater than on Ti in V, and Ti and Cu diffused faster than V in the joint.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46875689","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}
High-frequency (HF) induction welding is a practical welding technique widely used in various industries. Although it is generally robust, HF induction welding of aluminum tubes is complicated by the very high line speed, which requires high and accurate power input, and, therefore, a small fluctuation or variation in power input could result in drastically different welds. This work is dedicated to analyzing the influence of welding parameters, line speed, power input, and other unknown random factors, such as those induced by weather or work shift, especially those induced by the change of aluminum stock and adjustment/maintenance of the induction welding coil. Through the machine learning process, statistical models defining the normal operating windows were developed based on experimental data. The operating windows, defined by the overheat-normal and normal-cold boundaries, are expressed in terms of probabilities of producing normal welds. These trained models can be used to make new predictions, i.e., new operating windows, by collecting a small sample (a very limited number of calibrating data points). This procedure was verified experimentally.
{"title":"Predicting Operating Windows for High-Frequency Induction Aluminum Tube Welding","authors":"Shaowei Cheng, Hongyan Zhang","doi":"10.29391/2023.102.013","DOIUrl":"https://doi.org/10.29391/2023.102.013","url":null,"abstract":"High-frequency (HF) induction welding is a practical welding technique widely used in various industries. Although it is generally robust, HF induction welding of aluminum tubes is complicated by the very high line speed, which requires high and accurate power input, and, therefore, a small fluctuation or variation in power input could result in drastically different welds. This work is dedicated to analyzing the influence of welding parameters, line speed, power input, and other unknown random factors, such as those induced by weather or work shift, especially those induced by the change of aluminum stock and adjustment/maintenance of the induction welding coil. Through the machine learning process, statistical models defining the normal operating windows were developed based on experimental data. The operating windows, defined by the overheat-normal and normal-cold boundaries, are expressed in terms of probabilities of producing normal welds. These trained models can be used to make new predictions, i.e., new operating windows, by collecting a small sample (a very limited number of calibrating data points). This procedure was verified experimentally.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42370797","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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