Liu et al 2024a - Revision history

Rimni at 11:52, 21 May 2024

2024-05-21T11:52:19Z

Rimni: /* References */

2024-05-17T12:55:52Z

‎References

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Rimni at 12:03, 17 May 2024

2024-05-17T12:03:52Z

Rimni at 12:01, 17 May 2024

2024-05-17T12:01:19Z

Rimni at 11:39, 17 May 2024

2024-05-17T11:39:23Z

Rimni: /* 3.2.2 Welding parameters affect temperature distribution */

2024-05-17T11:39:01Z

‎3.2.2 Welding parameters affect temperature distribution

Rimni at 11:38, 17 May 2024

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Rimni at 11:30, 17 May 2024

2024-05-17T11:30:41Z

Rimni: /* 3. Parameter setting and result analysis */

2024-05-17T11:30:07Z

‎3. Parameter setting and result analysis

Rimni: /* 3. Parameter setting and result analysis */

2024-05-17T11:28:15Z

‎3. Parameter setting and result analysis

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 ==References==
 <div class="auto" style="text-align: left;width: auto; margin-left: auto; margin-right: auto;font-size: 85%;">
@@ Line 459: / Line 458: @@
 <span id='_Ref28247'></span>[[#cite-_Ref28247|[16]]]  Nie H.,  Xu Y.,  Ke L.M.,  Xing L. Effect of rotational speed on frictional heat production and interface structure of thick plate Al/Mg dissimilar materials by friction stir welding. Materials Reports, 37(08):88-93, 2023.
-<span id='_Ref28273'></span>[[#cite-_Ref28273|[17]]]  Kong D.B.,  Chen S.J.,  Jiang X.G. Study on morphology and intermetallic compounds of aluminum-magnesium disimillar alloy FSW joint. Hot Working Technology, 51(11):12-16, 2022.
+<span id='_Ref28273'></span>[[#cite-_Ref28273|[17]]]  Kong D.B.,  Chen S.J., Jiang X.G. Study on morphology and intermetallic compounds of aluminum-magnesium disimillar alloy FSW joint. Hot Working Technology, 51(11):12-16, 2022.
 <span id='_Ref28303'></span>[[#cite-_Ref28303|[18]]]  Kumar P.S.,  Das J.,  Shi Q.Y. Effect of alloying foil on the friction stir weld quality of Mg alloy joints. Metallography, Microstructure, and Analysis, 12(4):672-682, 2023.
-<span id='_Ref28326'></span>[[#cite-_Ref28326|[19]]] M. Bilgin, Ş. Karabulut, A. Özdemir. Investigation of Heat-Assisted Dissimilar Friction Stir Welding of AA7075-T6 Aluminum and AZ31B Magnesium Alloys. ''Arabian Journal for Science and Engineering'', 45 (64): 1081-1095, 2020.
+<span id='_Ref28326'></span>[[#cite-_Ref28326|[19]]]  Bilgin M.,  Karabulut Ş.,  Özdemir A. Investigation of heat-assisted dissimilar friction stir welding of AA7075-T6 aluminum and AZ31B magnesium alloys. Arabian Journal for Science and Engineering, 45(64):1081-1095, 2020.
-<span id='_Ref28371'></span>[[#cite-_Ref28371|[20]]] L. Xie, J.T. Wang, Y.L. Lu, L.Y. Sun, X.H. Yang. Microstructure and properties of bobbin-tool FSW for the 7075 aluminum alloy. ''Electric Welding Machine'', 49(02):55-59, 2019.
+<span id='_Ref28371'></span>[[#cite-_Ref28371|[20]]]  Xie L.,  Wang J.T.,  Lu Y.L.,  Sun L.Y.,  Yang X.H. Microstructure and properties of bobbin-tool FSW for the 7075 aluminum alloy. Electric Welding Machine, 49(02):55-59, 2019.
-<span id='_Ref28375'></span>[[#cite-_Ref28375|[21]]] R.J. Wang, M.X. Du, P.C. Zhang, Z.Q. Huang, Y. Huang, Z. Chen, X.G. Yan, L.F. Ma. Influence of milling process parameters on surface quality of AZ31B magnesium alloy. Transactions of Materials and Heat Treatment, 43 (11): 151-160, 2022.
+<span id='_Ref28375'></span>[[#cite-_Ref28375|[21]]]  Wang R.J.,  Du M.X.,  Zhang P.C.,  Huang Z.Q.,  Huang Y.,  Chen Z.,  Yan X.G.,  Ma L.F. Influence of milling process parameters on surface quality of AZ31B magnesium alloy. Transactions of Materials and Heat Treatment, 43(11):151-160, 2022.
-<span id='_Ref28512'></span>[[#cite-_Ref28512|[22]]] G.R. Johnson, W.H. Gook. Fracture character theistic of three metals subjected to various strains strain rates,temperatures and pressures. ''Engineering Fracture Mechanics'', 21(3):31-48, 1985.
+<span id='_Ref28512'></span>[[#cite-_Ref28512|[22]]]  Johnson G.R.,  Gook W.H. Fracture character theistic of three metals subjected to various strains strain rates,temperatures and pressures. Engineering Fracture Mechanics, 21(3):31-48, 1985.
-<span id='_Ref28927'></span>[[#cite-_Ref28927|[23]]] S. Zhang, J. Wang. Temperature Field of 6061 Aluminum Alloy by Friction Stir Welding Based on CEL Technique. ''Journal of Netshape Forming Engineering'', 15 (03): 64-71, 2023.
+<span id='_Ref28927'></span>[[#cite-_Ref28927|[23]]]  Zhang S.,  Wang J. Temperature field of 6061 aluminum alloy by friction stir welding based on CEL technique. Journal of Netshape Forming Engineering, 15(03):64-71, 2023.
-<span id='_Ref28675'></span>[[#cite-_Ref28675|[24]]] K.P. Mehta, P. Carlone, A. Astarita, F. Scherillo, F. Rubino, P. Vora. Conventional and cooling assisted friction stir welding of AA6061 and AZ31B alloys. ''Materials Science & Engineering A'', 759:252-261, 2019.
+<span id='_Ref28675'></span>[[#cite-_Ref28675|[24]]]  Mehta K.P.,  Carlone P.,  Astarita A.,  Scherillo F.,  Rubino F.,  Vora P. Conventional and cooling assisted friction stir welding of AA6061 and AZ31B alloys. Materials Science & Engineering A, 759:252-261, 2019.

@@ Line 402: / Line 402: @@
 |}
-=5. Conclusion=
+==5. Conclusions==
-<span id='OLE_LINK31'></span>This paper conducted a comprehensive study on numerical simulation of BT-FSW process for 7075/AZ31B aluminum/magnesium dissimilar alloy, and comprehensively analyzed the relationship between welding conditions, such as different rotating speed, welding speed, offset amount, and temperature field and stress field of Al-Mg dissimilar alloy BT-FSW process. Through the study, the following conclusions were drawn:
+This paper conducted a comprehensive study on numerical simulation of BT-FSW process for 7075/AZ31B aluminum/magnesium dissimilar alloy, and comprehensively analyzed the relationship between welding conditions, such as different rotating speed, welding speed, offset amount, and temperature field and stress field of Al-Mg dissimilar alloy BT-FSW process. Through the study, the following conclusions were drawn:
 (1) BT-FSW introduces two main heat sources, compared with single-sided welding, the rotating speed is relatively low, the axial temperature is "hourglass" shape symmetrical distribution, heat transfer is more uniform, and completely solves the problem of melting on the upper part of the Al-Mg dissimilar alloy plate and the bottom is not welded through.
-<span id='OLE_LINK32'></span><span id='OLE_LINK33'></span>(2) The offset of the stirring tool can effectively affect the welding temperature and stress distribution. Under the condition of no offset, the temperature distribution of the left and right plates is extremely uneven due to the huge difference in physical and chemical properties between the AZ31B and the 7075. When the stirring tool is migrated to the Mg side, the extreme situation that the magnesium alloy is melted while the aluminum alloy is still not thermoplastic appears. When the offset of the stirring tool to the Al side reaches 2mm, the temperature difference between Mg and Al sides is reduced to 33℃, the stress distribution is uniform, and the welding conditions are improved.
+(2) The offset of the stirring tool can effectively affect the welding temperature and stress distribution. Under the condition of no offset, the temperature distribution of the left and right plates is extremely uneven due to the huge difference in physical and chemical properties between the AZ31B and the 7075. When the stirring tool is migrated to the Mg side, the extreme situation that the magnesium alloy is melted while the aluminum alloy is still not thermoplastic appears. When the offset of the stirring tool to the Al side reaches 2mm, the temperature difference between Mg and Al sides is reduced to 33℃, the stress distribution is uniform, and the welding conditions are improved.
-<span id='OLE_LINK34'></span>(3) According to the calculation results of Scheme 4, 5, 6, 7 and 8, the rotating speed and slower welding speed faster, the heat input will be higher. When the rotating speed is 600r/min, the welding heat input will be insufficient, and the risk of material melting will occur when the rotating speed is increased to 800r/min. Only when the rotating speed is 700r/min and the welding speed is 180mm/min, the temperature of the Al/Mg alloy sheet reaches 90% of the melting point, and it is predicted that the flawless joint can be successfully formed at this time.
+(3) According to the calculation results of Scheme 4, 5, 6, 7 and 8, the rotating speed and slower welding speed faster, the heat input will be higher. When the rotating speed is 600r/min, the welding heat input will be insufficient, and the risk of material melting will occur when the rotating speed is increased to 800r/min. Only when the rotating speed is 700r/min and the welding speed is 180mm/min, the temperature of the Al/Mg alloy sheet reaches 90% of the melting point, and it is predicted that the flawless joint can be successfully formed at this time.
 (4) Changes in the positions of AZ31B magnesium alloy and 7075 aluminum alloy sheets directly affect the peak welding temperature and the temperature difference between Al and Mg alloy in the welding process. Specifically, when magnesium alloy is placed in AS, the peak welding temperature is higher under the same parameter conditions, and the temperature difference between the left and right sheets is suitable. When the magnesium alloy is placed in RS, the temperature difference between the welding peak temperature and the left and right plates decreases. In the BT-FSW welding of 7075 aluminum alloy and AZ31B magnesium alloy, the magnesium alloy is more inclined to be placed on the AS.
 ==Acknowledgments==
@@ Line 422: / Line 418: @@
 The author(s) disclosed receipt of the following ﬁnancial support for the research, authorship, and/or publication of this article: Henan Province Science and Technology Research Project (No. 222102240017, 232102241030), Zhengzhou University of Aeronautics laboratory opening project in 2024 (No.ZHSK2453, ZHSK2454, ZHSK2455), Henan Provincial Natural Science Foundation Project (No.232300420106), Scientific Research Team Plan of Zhengzhou University of Aeronautics （No.23ZHTD01006） for their support to this research.
-==Correspondence==
+'''Declaration of conﬂicting interests''': The author(s) declared no potential conﬂicts of interest with respect to the research, authorship, and/or publication of this article.
-−
-Guang Zeng, Associate professor, Master's supervisor, School of Aerospace Engineering, Zhengzhou University of Aeronautics, Zhengzhou, China. Email: [mailto:zengg8899@163.com zengg8899@163.com]
-The data that support the findings of this study are available from the corresponding author upon reasonable request.
+'''Data availability statement''': The data that support the findings of this study are available from the corresponding author upon reasonable request.
-==Reference==
+==References==
 <span id='_Ref26735'></span><span id='OLE_LINK35'></span>[[#cite-OLE_LINK35|[1]]] R.S. Singh, K. Raman, K. Ranvijay, G. Pankaj, S. Sehijpal, P.D. Yurievich, G. Khaled, A. Krzysztof. Joining of Dissimilar Al and Mg Metal Alloys by Friction Stir Welding. ''Materials'', 15(17): 5901-5901, 2022.

@@ Line 388: / Line 388: @@
 |}
-=4. Verification of simulation results=
+==4. Verification of simulation results==
-<span id='OLE_LINK30'></span>In order to verify the accuracy of the above simulation study in predicting the extreme temperature distribution anomalies and welding failure phenomena in the welding process of 7075-AZ31B dissimilar alloy, and further prove the reliability of the whole set of numerical analysis results, this study will conduct destructive welding experiments of 7075-AZ31B dissimilar alloy under extreme technological conditions. It was set to offset 1mm to the side of AZ31B magnesium alloy, the rotating speed was 800r/min, and the welding speed was 240mm/min. In addition, infrared temperature gun was used to measure the temperature of AS and RS in the stirring zone during the experiment for several times, and the temperature measurement results were compared with the temperature distribution data of numerical analysis. In addition, the simulation uses the same calculation method, boundary conditions, material parameters, predefined fields and other theoretical Settings as above, and performs the finite element simulation under the same parameter conditions as the experiment.
+In order to verify the accuracy of the above simulation study in predicting the extreme temperature distribution anomalies and welding failure phenomena in the welding process of 7075-AZ31B dissimilar alloy, and further prove the reliability of the whole set of numerical analysis results, this study will conduct destructive welding experiments of 7075-AZ31B dissimilar alloy under extreme technological conditions. It was set to offset 1mm to the side of AZ31B magnesium alloy, the rotating speed was 800r/min, and the welding speed was 240mm/min. In addition, infrared temperature gun was used to measure the temperature of AS and RS in the stirring zone during the experiment for several times, and the temperature measurement results were compared with the temperature distribution data of numerical analysis. In addition, the simulation uses the same calculation method, boundary conditions, material parameters, predefined fields and other theoretical Settings as above, and performs the finite element simulation under the same parameter conditions as the experiment.
-<span id='OLE_LINK29'></span>Figure 14 shows the comparison curve of temperature distribution data between the two. Due to the occlusion of the shoulder, infrared temperature measurement cannot directly measure the temperature in the stirring zone below the shoulder, so the measurement position is set to the material surface 11mm away from the weld center. Further observation of the morphology of the stirring zone after welding showed that the melting of Mg side was serious, leaving a large number of flash edges in the welding process, and causing a large number of material missing on the Mg side of the welded joint. However, the temperature of one side of the aluminum alloy is obviously low, and the material is insufficient in thermoplasticity. The difference of material states on both sides causes the aluminum alloy and the magnesium alloy deposited in front of the stirring tool to exert great tangential stress on the stirring tool during the welding process, resulting in the fracture of the stirring pin in the second half of the process. By comparing the temperature measured by experiment with the temperature data extracted by simulation, it is found that the distribution rules of the two are basically the same, and the data fit well, which effectively proves the accuracy of the numerical calculation model for predicting the abnormal distribution of temperature difference in the experiment.
+[[#img-14|Figure 14]] shows the comparison curve of temperature distribution data between the two. Due to the occlusion of the shoulder, infrared temperature measurement cannot directly measure the temperature in the stirring zone below the shoulder, so the measurement position is set to the material surface 11mm away from the weld center. Further observation of the morphology of the stirring zone after welding showed that the melting of Mg side was serious, leaving a large number of flash edges in the welding process, and causing a large number of material missing on the Mg side of the welded joint. However, the temperature of one side of the aluminum alloy is obviously low, and the material is insufficient in thermoplasticity. The difference of material states on both sides causes the aluminum alloy and the magnesium alloy deposited in front of the stirring tool to exert great tangential stress on the stirring tool during the welding process, resulting in the fracture of the stirring pin in the second half of the process. By comparing the temperature measured by experiment with the temperature data extracted by simulation, it is found that the distribution rules of the two are basically the same, and the data fit well, which effectively proves the accuracy of the numerical calculation model for predicting the abnormal distribution of temperature difference in the experiment.
-[[File:14.png|600x600px]]
+<div id='img-14'></div>
+{| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:auto;"
-<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
+|-style="background:white;"
-'''Figure 14.''' Comparison of experimental and numerical results</div>
+|style="text-align: center;padding:10px;"| [[File:14.png|600x600px]]
 =5. Conclusion=

@@ Line 367: / Line 367: @@
 Similar to traditional FSW, BT-FSW also has Advancing side (AS) and Retreating side (RS). In the same alloy FSW, RS temperature is often higher than AS, but dissimilar alloys do not follow this rule. The temperature difference between the two sides of the welding is often determined by the physical and chemical properties of the material. In previous studies, researchers have experimentally verified the excellent performance of placing magnesium alloy on the AS in the FSW process of 6061/AZ31B Al-Mg dissimilar alloy <span id='cite-_Ref28675'></span>[[#_Ref28675|[24]]]. Therefore, this study will for the first time use thermodynamic coupling simulation method to conduct numerical calculation research on the influence of the position change of dissimilar alloy BT-FSW plate on the welding temperature and stress distribution.
-AS shown in [[#img-12|Figure 12]] , the welding temperature and stress distribution nephogram diagram of AS and RS were successively placed on the magnesium alloy under the parameter conditions that the stirring tool was shifted to the side of the aluminum alloy and the rotating speed and welding speed were 700r/min and 180mm/min, respectively. It can be seen that no matter how the plate is placed, the stress distribution in the welding process is always relatively uniform, and there is no obvious change; When the magnesium alloy is on the AS, the peak temperature during the welding process is about 614℃, and when the magnesium alloy is placed on the RS under the same conditions, the peak temperature during the welding process is reduced (about 20℃). It can be inferred that placing the AZ31B magnesium alloy with lower strength on the AS is conducive to the production of welding heat. In order to ensure the same peak welding temperature at the same time can properly reduce the speed or increase the welding speed, which is helpful to obtain a good joint forming effect under low energy consumption.
+As shown in [[#img-12|Figure 12]] , the welding temperature and stress distribution nephogram diagram of AS and RS were successively placed on the magnesium alloy under the parameter conditions that the stirring tool was shifted to the side of the aluminum alloy and the rotating speed and welding speed were 700r/min and 180mm/min, respectively. It can be seen that no matter how the plate is placed, the stress distribution in the welding process is always relatively uniform, and there is no obvious change; When the magnesium alloy is on the AS, the peak temperature during the welding process is about 614℃, and when the magnesium alloy is placed on the RS under the same conditions, the peak temperature during the welding process is reduced (about 20℃). It can be inferred that placing the AZ31B magnesium alloy with lower strength on the AS is conducive to the production of welding heat. In order to ensure the same peak welding temperature at the same time can properly reduce the speed or increase the welding speed, which is helpful to obtain a good joint forming effect under low energy consumption.
 <div id='img-12'></div>

← Older revision		Revision as of 11:39, 17 May 2024
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−	The melting point of AZ31B magnesium alloy produced by different factories is mostly between 620-650℃, and 7075 aluminum alloy is between 580-610℃. The analysis of temperature nephogram and welding temperature rise curve shows that when the rotating speed is 700r/min and the welding speed is 240mm/min, the maximum temperature of magnesium and aluminum alloy is 589℃ and 507℃ respectively, and the heat input of Al side is obviously insufficient. When the rotating speed is 700r/min and the welding speed is 180mm/min, the maximum temperature in the welding process of magnesium and aluminum alloy reaches 605℃ and 546℃, reaching more than 90% of the respective melting point. At this temperature, there is sufficient thermoplastic material, almost no material is melted, the amount of intermetallic compound is less, and there is no solidification defect caused by cooling. Excellent welding effect and mechanical properties. When the rotating speed is 800r/min and the welding speed is 240mm/min or 180mm/min, the maximum temperature on the magnesium side during the welding process reaches 620℃ or above, and some magnesium alloys begin to melt at this temperature, and the production of brittle intermetallic compounds increases. Moreover, due to the high thermal expansion coefficient of magnesium alloy, solidification porosity defects will occur after welding cooling, which will reduce the mechanical properties after welding.	+	The melting point of AZ31B magnesium alloy produced by different factories is mostly between 620-650℃, and 7075 aluminum alloy is between 580-610℃. The analysis of temperature nephogram and welding temperature rise curve shows that when the rotating speed is 700r/min and the welding speed is 240mm/min, the maximum temperature of magnesium and aluminum alloy is 589℃ and 507℃, respectively, and the heat input of Al side is obviously insufficient. When the rotating speed is 700r/min and the welding speed is 180mm/min, the maximum temperature in the welding process of magnesium and aluminum alloy reaches 605℃ and 546℃, reaching more than 90% of the respective melting point. At this temperature, there is sufficient thermoplastic material, almost no material is melted, the amount of intermetallic compound is less, and there is no solidification defect caused by cooling. Excellent welding effect and mechanical properties. When the rotating speed is 800r/min and the welding speed is 240mm/min or 180mm/min, the maximum temperature on the magnesium side during the welding process reaches 620℃ or above, and some magnesium alloys begin to melt at this temperature, and the production of brittle intermetallic compounds increases. Moreover, due to the high thermal expansion coefficient of magnesium alloy, solidification porosity defects will occur after welding cooling, which will reduce the mechanical properties after welding.

	====3.2.3 The position of the plate affects the temperature and stress distribution====		====3.2.3 The position of the plate affects the temperature and stress distribution====

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 <div id='img-7'></div>
-{| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:65%;"
+{| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:50%;"
 |-style="background:white;"
 |style="text-align: center;padding:10px;"| [[Image:Draft_Zeng_363242613-image7.jpeg|center|400px]]

@@ Line 284: / Line 284: @@
 {| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:auto;"
 |-style="background:white;"
-|style="text-align: center;padding:10px;"| [[Image:Draft_Zeng_363242613-image6.jpeg|276px]]
+|style="text-align: center;padding:10px;"| [[Image:Draft_Zeng_363242613-image6.jpeg|400px]]
 |-
-| style="background:#efefef;text-align:left;padding:10px;font-size: 85%;"| '''Figure 6'''. Scheme 2 Temperature rise curve of random points in the mixing zone
+| style="background:#efefef;text-align:left;padding:10px;font-size: 85%;"| '''Figure 6'''. Scheme 2. Temperature rise curve of random points in the mixing zone
 |}
@@ Line 293: / Line 293: @@
 {| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:auto;"
 |-style="background:white;"
-|style="text-align: center;padding:10px;"| [[Image:Draft_Zeng_363242613-image7.jpeg|center|276px]]
+|style="text-align: center;padding:10px;"| [[Image:Draft_Zeng_363242613-image7.jpeg|center|400px]]
 |-
 | style="background:#efefef;text-align:left;padding:10px;font-size: 85%;"| '''Figure 7'''. Linear path temperature distribution curve from weld center to base metal area of scheme 1, 3 and 4
 |}
-<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
+Whether the stress distribution is uniform during the welding process can directly affect the forming quality of the welded joint, and further reflect whether the stirring action of the stirring tool on both sides of the alloy material is consistent. Now, in order to directly reflect the stress distribution law in the forming process of the joint, the stress distribution under the above offset condition and the condition of the stirring tool without offset is compared and analyzed, and the stress distribution nephogram with different offset quantities under the same parameters is shown in [[#img-8|Figure 8]]. On this basis, the 3D model of stress distribution on the welding surface is drawn, as shown in [[#img-9|Figure 9]] (the position of the lattice has been marked on the stress nephogram). In this model, the stress distribution is shown in the form of peaks, which are gentle in the region of low stress, and steep in the region of large difference in stress distribution.
-{|
 |-
-| [[Image:Draft_Zeng_363242613-image6.jpeg|276px]]
+| style="background:#efefef;text-align:left;padding:10px;font-size: 85%;"| '''Figure 8'''. Stress distribution nephogram under different offset conditions
-| [[Image:Draft_Zeng_363242613-image7.jpeg|center|276px]]
 |}
-random points in the mixing zone        curve from weld center to base metal area of scheme 1, 3 and 4
+<div id='img-9'></div>
+{| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:auto;"
-<span id='OLE_LINK15'></span><span id='OLE_LINK17'></span>Whether the stress distribution is uniform during the welding process can directly affect the forming quality of the welded joint, and further reflect whether the stirring action of the stirring tool on both sides of the alloy material is consistent. Now, in order to directly reflect the stress distribution law in the forming process of the joint, the stress distribution under the above offset condition and the condition of the stirring tool without offset is compared and analyzed, and the stress distribution nephogram with different offset quantities under the same parameters is shown in Figure 8. On this basis, the 3D model of stress distribution on the welding surface is drawn, as shown in Figure 9 (the position of the lattice has been marked on the stress nephogram). In this model, the stress distribution is shown in the form of peaks, which are gentle in the region of low stress, and steep in the region of large difference in stress distribution.
+|-style="background:white;"
+|style="text-align: center;padding:10px;"| [[Image:Draft_Zeng_363242613-image9.jpeg|498px]]
-<span id='OLE_LINK18'></span>When the stirring tool is not offset, the material on the Al side is not softened due to the large temperature difference between the left and right of the Al/Mg dissimilar alloy, and the stress generated under the intense agitation of the stirring tool is obviously higher than that on the Mg side, and the trend of the 3D stress graph is obvious. When the stirring tool is shifted to one side of the Al, the stress distribution in the welding process is more symmetrical, and the 3D stress map shows a symmetrical "W" shape trend. Therefore, in the BT-FSW process of 7075/AZ31B dissimilar alloy, in order to obtain a welded joint with no defects, high quality and uniform stress distribution, the stirring tool should be appropriately offset to the Al side, and the offset is determined by the actual parameters such as the shape and thickness of the stirring pin.
+|-
+| style="background:#efefef;text-align:left;padding:10px;font-size: 85%;"| '''Figure 9'''. 3D model of weld surface stress distribution
-<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
+|}
- [[Image:Draft_Zeng_363242613-image8.jpeg|456px]] </div>
-<div id="OLE_LINK20" class="center" style="width: auto; margin-left: auto; margin-right: auto;">
+When the stirring tool is not offset, the material on the Al side is not softened due to the large temperature difference between the left and right of the Al/Mg dissimilar alloy, and the stress generated under the intense agitation of the stirring tool is obviously higher than that on the Mg side, and the trend of the 3D stress graph is obvious. When the stirring tool is shifted to one side of the Al, the stress distribution in the welding process is more symmetrical, and the 3D stress map shows a symmetrical "W" shape trend. Therefore, in the BT-FSW process of 7075/AZ31B dissimilar alloy, in order to obtain a welded joint with no defects, high quality and uniform stress distribution, the stirring tool should be appropriately offset to the Al side, and the offset is determined by the actual parameters such as the shape and thickness of the stirring pin.
-'''Figure 9.''' 3D model of weld surface stress distribution</div>
-''3.2.2 Welding parameters affect temperature distribution''
+====3.2.2 Welding parameters affect temperature distribution====
-<span id='OLE_LINK21'></span>After determining the correct offset of the stirring pin, the process parameters are optimized for the design scheme 4, 5, 6, 7 and 8, and the rotating speed and welding speed are studied in turn under the condition that the offset of the stirring tool is unchanged. The temperature cloud image obtained at 600r/min-800r/min rotating speed and 180mm/min and 240mm/min welding speed is shown in Figure 10. The temperature cloud image of scheme 4 is shown in Figure 4(c).
+After determining the correct offset of the stirring pin, the process parameters are optimized for the design scheme 4, 5, 6, 7 and 8, and the rotating speed and welding speed are studied in turn under the condition that the offset of the stirring tool is unchanged. The temperature cloud image obtained at 600r/min-800r/min rotating speed and 180mm/min and 240mm/min welding speed is shown in [[#img-10|Figure 10]]. The temperature cloud image of scheme 4 is shown in [[#img-4|Figure 4]](c).
 <div class="center" style="width: auto; margin-left: auto; margin-right: auto;">