A new model of the material flow in rotary friction welding of tubes is proposed. The material flow proposed is based on 3D microcomputer tomography scans of welds performed with tungsten tracers. The tracers indicate a bifurcation of flow into two deformation paths. The material in Path 1 interacts with the weld interface and exhibits large azimuthal flow. The material in Path 2 transitions from axial to primarily radial flow with little or no azimuthal flow. The directional transition in this path is compared to orthogonal machining and equal channel angular pressing. The process to estimate the variables needed to calculate strain and strain rates using the equations from orthogonal machining and equal channel angular pressing is defined. Strain and strain rate in Path 2 are dependent upon feed rate and upset and decrease throughout the welding process. The strain rate is higher than previously reported for rotary friction welding as a result of the deformation model proposed.
{"title":"An Analytical Model of Material Deformation During Friction Welding of Alloy 718","authors":"Caleb Brown, Tracy W. NELSON, Carl Sorenson","doi":"10.29391/2024.103.014","DOIUrl":"https://doi.org/10.29391/2024.103.014","url":null,"abstract":"A new model of the material flow in rotary friction welding of tubes is proposed. The material flow proposed is based on 3D microcomputer tomography scans of welds performed with tungsten tracers. The tracers indicate a bifurcation of flow into two deformation paths. The material in Path 1 interacts with the weld interface and exhibits large azimuthal flow. The material in Path 2 transitions from axial to primarily radial flow with little or no azimuthal flow. The directional transition in this path is compared to orthogonal machining and equal channel angular pressing. The process to estimate the variables needed to calculate strain and strain rates using the equations from orthogonal machining and equal channel angular pressing is defined. Strain and strain rate in Path 2 are dependent upon feed rate and upset and decrease throughout the welding process. The strain rate is higher than previously reported for rotary friction welding as a result of the deformation model proposed.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140466063","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}
Improving the keyhole welding process window is challenging work because the force and thermal state in the weld pool are hard to control. A hybrid plasma-free arc source was developed based on a plasma arc torch, sided tungsten was added close to the constraint orifice to form a free arc, and hybrid arcs formed after the free arc was fully absorbed into the constraint arc. In such a one-anode, twocathode hybrid arc system, the added free arc acts in an assistant role to adjust arc heat output without influencing the arc pressure peak, and the constraint arc acts as the guiding arc to control the arc pressure and slightly incline to the free arc side. Bead-on welding experiments were done to test keyhole welding process behavior with the hybrid arc source, including arc column, keyhole state, weld surface performance, and melting state in the weld pool. Results showed that (1) the hybrid arc can enlarge the stable keyhole welding process window in aspects of welding current and welding speed, and a more-obvious improving effect is obtained with the leading-sided tungsten; (2) the hybrid arc with the rear-sided tungsten has a smooth front weld surface; (3) the increased heat will enlarge the weld cross-section area with no obvious influence to the backside weld width; and (4) the leading keyhole wall is related to the outer tungsten position. The research gives a new method for improving keyhole welding stability.
{"title":"Keyhole Welding with Hybrid Plasma-Free Arc Source","authors":"ZuMing Liu, Fei Liu, JiaYu Qiu","doi":"10.29391/2024/103.004","DOIUrl":"https://doi.org/10.29391/2024/103.004","url":null,"abstract":"Improving the keyhole welding process window is challenging work because the force and thermal state in the weld pool are hard to control. A hybrid plasma-free arc source was developed based on a plasma arc torch, sided tungsten was added close to the constraint orifice to form a free arc, and hybrid arcs formed after the free arc was fully absorbed into the constraint arc. In such a one-anode, twocathode hybrid arc system, the added free arc acts in an assistant role to adjust arc heat output without influencing the arc pressure peak, and the constraint arc acts as the guiding arc to control the arc pressure and slightly incline to the free arc side. Bead-on welding experiments were done to test keyhole welding process behavior with the hybrid arc source, including arc column, keyhole state, weld surface performance, and melting state in the weld pool. Results showed that (1) the hybrid arc can enlarge the stable keyhole welding process window in aspects of welding current and welding speed, and a more-obvious improving effect is obtained with the leading-sided tungsten; (2) the hybrid arc with the rear-sided tungsten has a smooth front weld surface; (3) the increased heat will enlarge the weld cross-section area with no obvious influence to the backside weld width; and (4) the leading keyhole wall is related to the outer tungsten position. The research gives a new method for improving keyhole welding stability.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139686465","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}
Abdul Sayeed Kahn, Pingsha Dong, Fengchao Liu, Yuning Zhang
Structural lightweighting through the effective use of multiple materials has received increasing attention for fulfilling today’s demands for environmental sustainability in transportation systems. Direct dissimilar material joining methods (versus, e.g., traditional adhesive bonding or mechanical fastening) have become increasingly desirable since they offer process simplicity, production efficiency, and hermetic sealing, among others. In Part I of this two-part article, we provided a critical assessment of the state-of-the-art research and promising direct dissimilar material joining techniques reported over the last decades, with a particular emphasis on their potential for structural applications. As such, in Part 2, recent advances in advanced joint design and modeling methods for enabling optimum joint design for joint ability and joint performance are presented along with some detailed examples for demonstrating their potential impacts on industrial applications. Finally, recommendations on future research and development directions are outlined for supporting the industry’s drive towards multi-material lightweighting.
{"title":"A State-of-the-Art Review on Direct Welding of Polymer to Metal for Structural Applications: Part 2 — Joint Design and Property Characterization","authors":"Abdul Sayeed Kahn, Pingsha Dong, Fengchao Liu, Yuning Zhang","doi":"10.29391/2024.103.013","DOIUrl":"https://doi.org/10.29391/2024.103.013","url":null,"abstract":"Structural lightweighting through the effective use of multiple materials has received increasing attention for fulfilling today’s demands for environmental sustainability in transportation systems. Direct dissimilar material joining methods (versus, e.g., traditional adhesive bonding or mechanical fastening) have become increasingly desirable since they offer process simplicity, production efficiency, and hermetic sealing, among others. In Part I of this two-part article, we provided a critical assessment of the state-of-the-art research and promising direct dissimilar material joining techniques reported over the last decades, with a particular emphasis on their potential for structural applications. As such, in Part 2, recent advances in advanced joint design and modeling methods for enabling optimum joint design for joint ability and joint performance are presented along with some detailed examples for demonstrating their potential impacts on industrial applications. Finally, recommendations on future research and development directions are outlined for supporting the industry’s drive towards multi-material lightweighting.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140464413","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 effect of boron on stress-relief cracking (SRC) sensitivity in the coarse grain heat-affected zone (CGHAZ) of ASME SA213-T23 was studied by thermo-mechanical simulation. Then, the fracture mode, microstructure, carbide evolution, and boron segregation were observed by an optical microscope, a scanning electron microscope, a transmission electron microscope, and an electron probe microanalyzer. Finally, the mechanism of increasing boron content to improve SRC resistance was described. The results showed that when the boron content is lower than 0.0038 wt.-%, T23 steel is sensitive to SRC at 550–750°C (1022–1382°F), and the sensitive temperature range narrows as the boron content increases. When the boron content increases to 0.010 wt.-%, SRC can be eliminated. Moreover, boron addition did not improve grain boundary (GB) strength nor did it fundamentally change the fracture mode at high temperatures, but it significantly improved intergranular ductility. This is because the boron segregation at the GB inhibits the precipitation of M23C6 carbides, which reduces the void nucleation and alloy element depletion near the GB, thus significantly improving intergranular plasticity. The improvement of intergranular plasticity gives the grain sufficient time to deform and greatly improves the overall plasticity of the CGHAZ. As a result, the SRC resistance of the welded joint is significantly improved because the stress can be released through enough plastic deformation during postweld heat treatment or service.
{"title":"Influence of Boron on Stress-Relief Cracking Susceptibility of T23 Steel","authors":"Dongdong Zhang, Xue Wang","doi":"10.29391/2024.103.001","DOIUrl":"https://doi.org/10.29391/2024.103.001","url":null,"abstract":"The effect of boron on stress-relief cracking (SRC) sensitivity in the coarse grain heat-affected zone (CGHAZ) of ASME SA213-T23 was studied by thermo-mechanical simulation. Then, the fracture mode, microstructure, carbide evolution, and boron segregation were observed by an optical microscope, a scanning electron microscope, a transmission electron microscope, and an electron probe microanalyzer. Finally, the mechanism of increasing boron content to improve SRC resistance was described. The results showed that when the boron content is lower than 0.0038 wt.-%, T23 steel is sensitive to SRC at 550–750°C (1022–1382°F), and the sensitive temperature range narrows as the boron content increases. When the boron content increases to 0.010 wt.-%, SRC can be eliminated. Moreover, boron addition did not improve grain boundary (GB) strength nor did it fundamentally change the fracture mode at high temperatures, but it significantly improved intergranular ductility. This is because the boron segregation at the GB inhibits the precipitation of M23C6 carbides, which reduces the void nucleation and alloy element depletion near the GB, thus significantly improving intergranular plasticity. The improvement of intergranular plasticity gives the grain sufficient time to deform and greatly improves the overall plasticity of the CGHAZ. As a result, the SRC resistance of the welded joint is significantly improved because the stress can be released through enough plastic deformation during postweld heat treatment or service.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126266","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}
Friction stir welding (FSW) process parameters influence welding temperature field and axial force, which affect welding strength. At present, how the FSW process parameters of aluminum alloy 2219-T8 thick plates influence process physical quantity and how the process physical quantity changes the tensile strength about the welded joint are unknown. We focus on the intelligent prediction of FSW temperature, axial force, and mechanical properties, to provide a basis for FSW process control of aluminum alloy 2219-T8 thick plate. Firstly, we conducted the FSW experiment of aluminum alloy 2219-T8 thick plate. Then, we input the welding process parameters, set up a prediction model by particle swarm optimization-back propagation (PSO-BP) neural network to predict the peak temperature and axial force. Finally, we input the peak temperature and axial force, use genetic algorithm-back propagation (GA-BP) neural network to establish a weld tensile strength estimation model, and comply with the prediction of tensile strength.
{"title":"Intelligent Prediction of FSW Physical Quantity and Joint Mechanical Properties","authors":"Xiaohong Lu, Fanmao Zeng, Y. Luan, X. Meng","doi":"10.29391/2024.103.002","DOIUrl":"https://doi.org/10.29391/2024.103.002","url":null,"abstract":"Friction stir welding (FSW) process parameters influence welding temperature field and axial force, which affect welding strength. At present, how the FSW process parameters of aluminum alloy 2219-T8 thick plates influence process physical quantity and how the process physical quantity changes the tensile strength about the welded joint are unknown. We focus on the intelligent prediction of FSW temperature, axial force, and mechanical properties, to provide a basis for FSW process control of aluminum alloy 2219-T8 thick plate. Firstly, we conducted the FSW experiment of aluminum alloy 2219-T8 thick plate. Then, we input the welding process parameters, set up a prediction model by particle swarm optimization-back propagation (PSO-BP) neural network to predict the peak temperature and axial force. Finally, we input the peak temperature and axial force, use genetic algorithm-back propagation (GA-BP) neural network to establish a weld tensile strength estimation model, and comply with the prediction of tensile strength.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126000","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}
XIN-MIN Shi, DE-FENG Mo, Tong Zhao, Yang Zhang, Wen Sun, HAI-MEI Gong, Xue Li
Electron beam welding of pure molybdenum (Mo) and titanium alloy (Ti-6Al-4V) was performed with beam oscillation. The effects of beam oscillation with offset on the welded joints were analyzed in terms of microstructure, element distribution, chemical composition, microhardness, and tensile strength. The results showed that the fusion zone expanded with beam oscillation. Reaction layers were generated in both joints welded with and without beam oscillation. The thickness of the reaction layers decreased along the perpendicular direction. The reaction layers were (Mo, Ti) solid solutions. Both welded joints consisted of single-phase Mo, the β-Ti phase, and Mo-Ti solid solutions. The microhardness distribution of the joint welded with beam oscillation was more consistent than that of the joint welded without beam oscillation, and the maximum hardness was reduced from 340 HV to 270 HV. The tensile strength increased from 124 MPa to 204 MPa.
{"title":"Effect of Electron Beam Oscillation Welding of Molybdenum and Titanium","authors":"XIN-MIN Shi, DE-FENG Mo, Tong Zhao, Yang Zhang, Wen Sun, HAI-MEI Gong, Xue Li","doi":"10.29391/2024.103.003","DOIUrl":"https://doi.org/10.29391/2024.103.003","url":null,"abstract":"Electron beam welding of pure molybdenum (Mo) and titanium alloy (Ti-6Al-4V) was performed with beam oscillation. The effects of beam oscillation with offset on the welded joints were analyzed in terms of microstructure, element distribution, chemical composition, microhardness, and tensile strength. The results showed that the fusion zone expanded with beam oscillation. Reaction layers were generated in both joints welded with and without beam oscillation. The thickness of the reaction layers decreased along the perpendicular direction. The reaction layers were (Mo, Ti) solid solutions. Both welded joints consisted of single-phase Mo, the β-Ti phase, and Mo-Ti solid solutions. The microhardness distribution of the joint welded with beam oscillation was more consistent than that of the joint welded without beam oscillation, and the maximum hardness was reduced from 340 HV to 270 HV. The tensile strength increased from 124 MPa to 204 MPa.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126791","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}
N. Sridharan, Yousub Lee, Brian Jordan, John Robertson, Ramesh Ramakrishnan
This article describes the ability to use laser-blown powder deposition to repair high γ’ IN-100 superalloy gas turbine components. The influence of various process conditions on the ability to make crack-free IN-100 deposits over surrogate high γʹ alloys was investigated to identify cracking mechanisms in the deposit and heat-affected zones (HAZs). The various crack formation mechanisms, such as solidification cracking and liquation cracking, were evaluated using multiscale characterization and numerical simulation. The cracking in the deposit region was predominantly solidification cracking, while those observed in the HAZ were liquation cracking. The results showed that controlling thermally induced residual stresses is the key to eliminating cracking, and the optimum preheat temperature was determined. The results were then contrasted with those in published literature and an approach to effectively repair hot section parts was presented.
{"title":"Repairing High γ’ Hot Section Gas Turbine Components Using Advanced Manufacturing","authors":"N. Sridharan, Yousub Lee, Brian Jordan, John Robertson, Ramesh Ramakrishnan","doi":"10.29391/2023.102.023","DOIUrl":"https://doi.org/10.29391/2023.102.023","url":null,"abstract":"This article describes the ability to use laser-blown powder deposition to repair high γ’ IN-100 superalloy gas turbine components. The influence of various process conditions on the ability to make crack-free IN-100 deposits over surrogate high γʹ alloys was investigated to identify cracking mechanisms in the deposit and heat-affected zones (HAZs). The various crack formation mechanisms, such as solidification cracking and liquation cracking, were evaluated using multiscale characterization and numerical simulation. The cracking in the deposit region was predominantly solidification cracking, while those observed in the HAZ were liquation cracking. The results showed that controlling thermally induced residual stresses is the key to eliminating cracking, and the optimum preheat temperature was determined. The results were then contrasted with those in published literature and an approach to effectively repair hot section parts was presented.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139013643","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}
LU WANG, Y. Rong, YU HUANG, JIAJUN XU, JIANG HU, Guojun Zhang
Residual stress of laser-welded marine steel EH40 was experimentally and numerically analyzed considering weld defects (collapse, hump, and unfitness) and solid-state phase transformation (SSPT). A double-cylindrical source model was used to simulate the temperature distribution. The mean prediction errors of the model without and with weld defects along the plate thickness were 9.2 and 3.5%. Based on the thermodynamics of SSPT, microstructure fractions were computed and verified by weld hardness test results. Under the effect of SSPT, residual stress changed from compressive stress to tensile stress with the increase of the distance from the weld center. Weld defects have an influence on the value of residual stress, and this effect was greater when SSPT was considered. The affected zone extended from the vicinity of weld defects to the whole weld. The variations of longitudinal residual stress (LRS) and transverse residual stress (TRS) caused by weld defects and SSPT both exceeded 150 MPa. LRS was mainly affected by the loss and increase of metal, while TRS was affected by the stress concentration caused by shape geometry changes. Thus, the influence of weld defects on TRS was greater than that on LRS. The proposed finite element model considering weld defects and SSPT can be used to accurately predict residual stress in laser welding of marine steel EH40 and provide a theoretical basis to reduce welding stress.
{"title":"Stress Distribution of EH40 with Defects Considering Solid-State Phase Transformation","authors":"LU WANG, Y. Rong, YU HUANG, JIAJUN XU, JIANG HU, Guojun Zhang","doi":"10.29391/2023.102.024","DOIUrl":"https://doi.org/10.29391/2023.102.024","url":null,"abstract":"Residual stress of laser-welded marine steel EH40 was experimentally and numerically analyzed considering weld defects (collapse, hump, and unfitness) and solid-state phase transformation (SSPT). A double-cylindrical source model was used to simulate the temperature distribution. The mean prediction errors of the model without and with weld defects along the plate thickness were 9.2 and 3.5%. Based on the thermodynamics of SSPT, microstructure fractions were computed and verified by weld hardness test results. Under the effect of SSPT, residual stress changed from compressive stress to tensile stress with the increase of the distance from the weld center. Weld defects have an influence on the value of residual stress, and this effect was greater when SSPT was considered. The affected zone extended from the vicinity of weld defects to the whole weld. The variations of longitudinal residual stress (LRS) and transverse residual stress (TRS) caused by weld defects and SSPT both exceeded 150 MPa. LRS was mainly affected by the loss and increase of metal, while TRS was affected by the stress concentration caused by shape geometry changes. Thus, the influence of weld defects on TRS was greater than that on LRS. The proposed finite element model considering weld defects and SSPT can be used to accurately predict residual stress in laser welding of marine steel EH40 and provide a theoretical basis to reduce welding stress.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139020582","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 proposed a novel welding strategy called active-expulsion-assisted resistance spot welding (RSW), which was used to address the limitations of RSW of aluminum to steel. The method primarily comprised an intentionally set expulsion stage and a locking stage. In the expulsion stage, a short-duration expulsion pulse with a relatively large welding current was applied to melt the aluminum and induce liquid aluminum expulsion. Then, in the locking stage, a welding current pulse was used to join the locking sheet and the steel workpiece. A combination of quenched and partitioned 1180 steel and AA6016 aluminum alloy with and without adhesive was used for welding. Experimental results showed that the expulsion pulse efficiently removed the aluminum alloy in the weld, creating the conditions for fundamentally avoiding the formation of brittle intermetallic compounds in the nugget during the subsequent welding stage. After the welding pulse, a strong joint was generated between the locking sheet and the steel, thus realizing a firm connection for the combination of welding and riveting between an aluminum alloy and steel substrate.
{"title":"A Novel Strategy for Realizing Reliable Welding of Aluminum-Steel","authors":"Mingfeng Li, Yanjun Wang, Wu Tao, SHANGLU YANG","doi":"10.29391/2023.102.022","DOIUrl":"https://doi.org/10.29391/2023.102.022","url":null,"abstract":"This study proposed a novel welding strategy called active-expulsion-assisted resistance spot welding (RSW), which was used to address the limitations of RSW of aluminum to steel. The method primarily comprised an intentionally set expulsion stage and a locking stage. In the expulsion stage, a short-duration expulsion pulse with a relatively large welding current was applied to melt the aluminum and induce liquid aluminum expulsion. Then, in the locking stage, a welding current pulse was used to join the locking sheet and the steel workpiece. A combination of quenched and partitioned 1180 steel and AA6016 aluminum alloy with and without adhesive was used for welding. Experimental results showed that the expulsion pulse efficiently removed the aluminum alloy in the weld, creating the conditions for fundamentally avoiding the formation of brittle intermetallic compounds in the nugget during the subsequent welding stage. After the welding pulse, a strong joint was generated between the locking sheet and the steel, thus realizing a firm connection for the combination of welding and riveting between an aluminum alloy and steel substrate.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138992105","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}
YU HONG, TIMOTHY PICKLE, ZHENZHEN YU, JUDITH VIDAL, CHAD AUGUSTINE
Weldments of 347H stainless steel are potentially susceptible to stress relaxation cracking at elevated service temperatures. Mitigation of stress relaxation cracking susceptibility within a multipass weld requires a good understanding of welding practices and manufacturing techniques to control high tensile residual stresses. In this work, the dependence of residual stress distribution in 347H stainless steel on base plate thickness, joint geometry design, and preheating condition was systematically investigated by using three-dimensional finite element models. The finite element models were validated through good agreement between neutron diffraction measurements and calculated elastic strains. The single-V-groove welds with and without a preheating step all produced similar peak von Mises residual stresses, above 450 MPa, within both the fusion zone and heat-affected zone (HAZ). In plates thicker than 0.5 in. (12.7 mm), high tensile residual stress could be observed in a relatively large area, from the middle of the plate thickness to underneath the top surface. A double-V groove shifted the high tensile stress area to the middle thickness of the weld. A single-J-groove weld was able to confine the residual stress to a very small region near the middle thickness within the fusion zone and suppressed the von Mises residual stress within the HAZ to below 400 MPa.
{"title":"Impact of Plate Thickness and Joint Geometry on Residual Stresses in 347H Stainless Steel Welds","authors":"YU HONG, TIMOTHY PICKLE, ZHENZHEN YU, JUDITH VIDAL, CHAD AUGUSTINE","doi":"10.29391/2023.102.021","DOIUrl":"https://doi.org/10.29391/2023.102.021","url":null,"abstract":"Weldments of 347H stainless steel are potentially susceptible to stress relaxation cracking at elevated service temperatures. Mitigation of stress relaxation cracking susceptibility within a multipass weld requires a good understanding of welding practices and manufacturing techniques to control high tensile residual stresses. In this work, the dependence of residual stress distribution in 347H stainless steel on base plate thickness, joint geometry design, and preheating condition was systematically investigated by using three-dimensional finite element models. The finite element models were validated through good agreement between neutron diffraction measurements and calculated elastic strains. The single-V-groove welds with and without a preheating step all produced similar peak von Mises residual stresses, above 450 MPa, within both the fusion zone and heat-affected zone (HAZ). In plates thicker than 0.5 in. (12.7 mm), high tensile residual stress could be observed in a relatively large area, from the middle of the plate thickness to underneath the top surface. A double-V groove shifted the high tensile stress area to the middle thickness of the weld. A single-J-groove weld was able to confine the residual stress to a very small region near the middle thickness within the fusion zone and suppressed the von Mises residual stress within the HAZ to below 400 MPa.","PeriodicalId":23681,"journal":{"name":"Welding Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135111269","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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