静止轴肩对FSW温度与应力影响的数值模拟
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摘要
目的研究外部辅助静止轴肩对搅拌摩擦焊接过程温度场以及应力场的影响。方法建立有限模型并采用热机耦合的方法分析常规与静止轴肩辅助工艺下7075-T6铝合金搅拌摩擦焊接过程,得出不同工艺下的焊接温度与应力分布状态。对比常规与静止轴肩工艺下的温度与应力结果,得出静止轴肩对焊接过程中温度与应力的影响规律。结果焊缝横截面的高温区域均呈现出上宽下窄的碗型分布。相比于常规工艺,静止轴肩辅助工艺的焊缝区域温度具有上升速度较慢、下降速度较快的特点,且温度峰值低了55.7℃。静止轴肩具有随焊碾压的作用,在焊接过程中为焊缝区域提供一个额外的压应力,抵消焊接过程中产生的拉应力,焊后残余应力降低了17.4%。结论静止轴肩辅助工艺对焊缝区域的温度峰值以及残余应力峰值的降低均具有明显效果。
The paper aims to study on effects of external stationary shoulder on temperature and stress fields during friction stir welding process. A finite element model was set up and the thermal-mechanical coupled numerical simulation method was employed to analyze the welding process of 7075-T6 aluminum alloy under conventional and external stationary shoulder processes. Temperature and stress distributions were obtained under different welding processes. Effects of stationary shoulder on welding process were obtained by comparing the results of temperature and stress fields under conventional and external stationary shoulder processes. The high temperature region of the cross-section presented a bowl-shaped distribution of wide upper and narrow lower. Compared with the conventional process, temperature of stationary shoulder process had the characteristics of slower rise and faster drop rates, and the value of peak temperature in the weld was reduce by 55.7 ℃. Moreover, stationary shoulder had the effect of synchronous rolling. An external suppress stress was added to the weld, which could reduce the tensile welding stress produced in the welding process. The addition of stationary shoulder can reduce the peak residual stress by 17.4%.The peak values of temperature and residual stress in the weld area can be reduced by external stationary shoulder.
The paper aims to study on effects of external stationary shoulder on temperature and stress fields during friction stir welding process. A finite element model was set up and the thermal-mechanical coupled numerical simulation method was employed to analyze the welding process of 7075-T6 aluminum alloy under conventional and external stationary shoulder processes. Temperature and stress distributions were obtained under different welding processes. Effects of stationary shoulder on welding process were obtained by comparing the results of temperature and stress fields under conventional and external stationary shoulder processes. The high temperature region of the cross-section presented a bowl-shaped distribution of wide upper and narrow lower. Compared with the conventional process, temperature of stationary shoulder process had the characteristics of slower rise and faster drop rates, and the value of peak temperature in the weld was reduce by 55.7 ℃. Moreover, stationary shoulder had the effect of synchronous rolling. An external suppress stress was added to the weld, which could reduce the tensile welding stress produced in the welding process. The addition of stationary shoulder can reduce the peak residual stress by 17.4%.The peak values of temperature and residual stress in the weld area can be reduced by external stationary shoulder.
引文
[1]HUANG Y X,WAN L,LYU S X,et al.In Situ Rolling Friction Stir Welding for Joining AA2219[J].Materials&Design,2013,50(17):810-816.
[2]HUANG X,REYNOLDS A P.Effects of the Friction Stir Welding Process Variants on Residual Stress[J].Science and Technology of Welding&Joining,2017,23(5):1-8.
[3]牛鹏亮,李文亚.搅拌摩擦焊残余应力研究现状及展望[J].精密成形工程,2015,7(5):1-6.NIU Peng-liang,LI Wen-ya.Present Dtudy and Prospect of Friction Stir Welding Residual Stress[J].Journal of Netshape Forming Engineering,2015,7(5):1-6.
[4]刘其鹏,王忠旭,高月华,等.轨道车辆型材结构搅拌摩擦焊残余状态研究[J].精密成形工程,2018,10(4):101-107.LIU Qi-peng,WANG Zhong-xu,GAO Yue-hua,et al.Residual State of Friction Stir Welding of Rail Vehicle Profile Structures[J].Journal of Netshape Forming Engineering,2018,10(4):101-107.
[5]刘建光,胡忠民,吴为.铝合金加筋壁板搅拌摩擦焊接残余应力及变形分析[J].精密成形工程,2017,9(4):101-105.LIU Jian-guang,HU Zhong-min,WU Wei.Residual Stress and Deformation in Friction Stir Welding of Aluminium Stiffened Panel[J].Journal of Netshape Forming Engineering,2017,9(4):101-105.
[6]CHEN Y,LIU H,FENG J.Friction Stir Welding Characteristics of Different Heat-treated-state 2219 Aluminum Alloy Plates[J].Materials Science&Engineering A,2006,420(1/2):21-25.
[7]JI S D,FANG H Y,LIU X S,et al.Influence of Welding Sequence on Welding Residual Stress of Thick Plate[J].Modelling and Simulation in Materials Science and Engineering,2005,13(4):553-565.
[8]JI S D,LI Z W,ZHANG L G,ZHOU Z L,et al.Effect of Lap Configuration on Magnesium to Aluminum Friction Stir Lap Welding Assisted by External Stationary Shoulder[J].Materials&Design,2016,103:160-170.
[9]AVETTAND-FENOL M N,TAILLARD R.Effect of a Pre or Postweld Heat Treatment on Microstructure and Mechanical Properties of an AA2050 Weld Obtained by SSFSW[J].Materials&Design,2016,89:348-361.
[10]姬书得.搅拌头旋转频率对静止轴肩搅拌摩擦焊接头力学性能的影响规律[J].焊接学报,2015,36(1):51-54.JI Shu-de.Effect of Rotational Tool Frequency on Mechanical Properties of External Friction Stir Welding Joint[J].Transactions of the China Welding Institution,2015,36(1):51-54.
[11]LI D,YANG X,CUI L,et al.Investigation of Stationary Shoulder Friction Stir Welding of Aluminum Alloy7075-T651[J].Journal of Materials Processing Technology,2015,222:391-398.
[12]LI J Q,LIU H J.Effects of Tool Rotation Speed on Microstructures and Mechanical Properties of AA2219-T6Welded by the External Non-rotational Shoulder Assisted Friction Stir Welding[J].Materials&Design,2013,43:299-306.
[13]SUN T,ROY M J,STRONG D,et al.Comparison of Residual Stress Distributions in Conventional and Stationary Shoulder High-strength Aluminum Alloy Friction Stir Welds[J].Journal of Materials Processing Technology,2017,242:92-100.
[14]郭柱,朱浩,崔少朋,等.7075铝合金搅拌摩擦焊接头温度场及残余应力场的有限元模拟[J].焊接学报,2015,36(2):92-96.GUO Zhu,ZHU Hao,CUI Shao-peng,et al.Numerical Simulation of Temperature and Residual Stress of 7075Aluminum Alloy by Friction Stir Welding Joint[J].Transactions of the China Welding Institution,2015,36(2):92-96.
[15]杨建国,周号,雷靖,等.焊接应力与变形数值模拟领域的若干关键问题[J].焊接,2014(3):8-17.YANG Jian-guo,ZHOU Hao,LEI Jing,et al.Some Key Problems in the Field of Welding Stress and Deformation Numerical Simulation[J].Welding&Joining,2014(3):8-17.
[16]RAJAKUMAR S,MURALIDHARAN C,BALASUBR-AMANIAN V.Influence of Friction Stir Welding Process and Tool Parameters on Strength Properties of AA7075-T6Aluminum Alloy Joints[J].Materials&Design,2011,32(2):535-549.
[17]姬书得,卓彬,高双胜,等.TC4钛合金静止轴肩和传统搅拌摩擦焊的温度场对比[J].航空制造技术,2016,59(19):98-101.JI Shu-de,ZHUO Bin,GAO Shuang-sheng,et al.Temperature Field Comparison of TC4 Titanium Between Stationary Shoulder Friction Stir Welding and Traditional Friction Stir Welding.Aeronautical Manufacturing Technology,2016,59(19):98-101.
[18]HUANG Y X,MENG X C,XIE Y M,et al.Joining of Carbon Fiber Reinforced Thermoplastic and Metal Via Friction Stir Welding with Co-controlling Shape and Performance[J].Composites Part A:Applied Science and Manufacturing,2018,112:328-336.
[19]FENG A H,CHEN D L,MA Z Y.Microstructure and Cyclic Deformation Behavior of a Friction-Stir-Welded 7075Al Alloy[J].Metallurgical&Materials Transactions A,2010,41(4):957-971.
[20]RICHARDS D G,PRANGNELL P B,WITHERS P J,et al.Efficacy of Active Cooling for Controlling Residual Stresses in Friction Stir Welds[J].Science and Technology of Welding and Joining,2010,15(2):156-165.
[21]ALTENKIRCH J,STEUWER A,PEEL M,et al.The Effect of Tensioning and Sectioning on Residual Stresses in Aluminum AA7749 Friction Stir Welds[J].Materials Science and Engineering:A,2008,488(1/2):16-24.
[2]HUANG X,REYNOLDS A P.Effects of the Friction Stir Welding Process Variants on Residual Stress[J].Science and Technology of Welding&Joining,2017,23(5):1-8.
[3]牛鹏亮,李文亚.搅拌摩擦焊残余应力研究现状及展望[J].精密成形工程,2015,7(5):1-6.NIU Peng-liang,LI Wen-ya.Present Dtudy and Prospect of Friction Stir Welding Residual Stress[J].Journal of Netshape Forming Engineering,2015,7(5):1-6.
[4]刘其鹏,王忠旭,高月华,等.轨道车辆型材结构搅拌摩擦焊残余状态研究[J].精密成形工程,2018,10(4):101-107.LIU Qi-peng,WANG Zhong-xu,GAO Yue-hua,et al.Residual State of Friction Stir Welding of Rail Vehicle Profile Structures[J].Journal of Netshape Forming Engineering,2018,10(4):101-107.
[5]刘建光,胡忠民,吴为.铝合金加筋壁板搅拌摩擦焊接残余应力及变形分析[J].精密成形工程,2017,9(4):101-105.LIU Jian-guang,HU Zhong-min,WU Wei.Residual Stress and Deformation in Friction Stir Welding of Aluminium Stiffened Panel[J].Journal of Netshape Forming Engineering,2017,9(4):101-105.
[6]CHEN Y,LIU H,FENG J.Friction Stir Welding Characteristics of Different Heat-treated-state 2219 Aluminum Alloy Plates[J].Materials Science&Engineering A,2006,420(1/2):21-25.
[7]JI S D,FANG H Y,LIU X S,et al.Influence of Welding Sequence on Welding Residual Stress of Thick Plate[J].Modelling and Simulation in Materials Science and Engineering,2005,13(4):553-565.
[8]JI S D,LI Z W,ZHANG L G,ZHOU Z L,et al.Effect of Lap Configuration on Magnesium to Aluminum Friction Stir Lap Welding Assisted by External Stationary Shoulder[J].Materials&Design,2016,103:160-170.
[9]AVETTAND-FENOL M N,TAILLARD R.Effect of a Pre or Postweld Heat Treatment on Microstructure and Mechanical Properties of an AA2050 Weld Obtained by SSFSW[J].Materials&Design,2016,89:348-361.
[10]姬书得.搅拌头旋转频率对静止轴肩搅拌摩擦焊接头力学性能的影响规律[J].焊接学报,2015,36(1):51-54.JI Shu-de.Effect of Rotational Tool Frequency on Mechanical Properties of External Friction Stir Welding Joint[J].Transactions of the China Welding Institution,2015,36(1):51-54.
[11]LI D,YANG X,CUI L,et al.Investigation of Stationary Shoulder Friction Stir Welding of Aluminum Alloy7075-T651[J].Journal of Materials Processing Technology,2015,222:391-398.
[12]LI J Q,LIU H J.Effects of Tool Rotation Speed on Microstructures and Mechanical Properties of AA2219-T6Welded by the External Non-rotational Shoulder Assisted Friction Stir Welding[J].Materials&Design,2013,43:299-306.
[13]SUN T,ROY M J,STRONG D,et al.Comparison of Residual Stress Distributions in Conventional and Stationary Shoulder High-strength Aluminum Alloy Friction Stir Welds[J].Journal of Materials Processing Technology,2017,242:92-100.
[14]郭柱,朱浩,崔少朋,等.7075铝合金搅拌摩擦焊接头温度场及残余应力场的有限元模拟[J].焊接学报,2015,36(2):92-96.GUO Zhu,ZHU Hao,CUI Shao-peng,et al.Numerical Simulation of Temperature and Residual Stress of 7075Aluminum Alloy by Friction Stir Welding Joint[J].Transactions of the China Welding Institution,2015,36(2):92-96.
[15]杨建国,周号,雷靖,等.焊接应力与变形数值模拟领域的若干关键问题[J].焊接,2014(3):8-17.YANG Jian-guo,ZHOU Hao,LEI Jing,et al.Some Key Problems in the Field of Welding Stress and Deformation Numerical Simulation[J].Welding&Joining,2014(3):8-17.
[16]RAJAKUMAR S,MURALIDHARAN C,BALASUBR-AMANIAN V.Influence of Friction Stir Welding Process and Tool Parameters on Strength Properties of AA7075-T6Aluminum Alloy Joints[J].Materials&Design,2011,32(2):535-549.
[17]姬书得,卓彬,高双胜,等.TC4钛合金静止轴肩和传统搅拌摩擦焊的温度场对比[J].航空制造技术,2016,59(19):98-101.JI Shu-de,ZHUO Bin,GAO Shuang-sheng,et al.Temperature Field Comparison of TC4 Titanium Between Stationary Shoulder Friction Stir Welding and Traditional Friction Stir Welding.Aeronautical Manufacturing Technology,2016,59(19):98-101.
[18]HUANG Y X,MENG X C,XIE Y M,et al.Joining of Carbon Fiber Reinforced Thermoplastic and Metal Via Friction Stir Welding with Co-controlling Shape and Performance[J].Composites Part A:Applied Science and Manufacturing,2018,112:328-336.
[19]FENG A H,CHEN D L,MA Z Y.Microstructure and Cyclic Deformation Behavior of a Friction-Stir-Welded 7075Al Alloy[J].Metallurgical&Materials Transactions A,2010,41(4):957-971.
[20]RICHARDS D G,PRANGNELL P B,WITHERS P J,et al.Efficacy of Active Cooling for Controlling Residual Stresses in Friction Stir Welds[J].Science and Technology of Welding and Joining,2010,15(2):156-165.
[21]ALTENKIRCH J,STEUWER A,PEEL M,et al.The Effect of Tensioning and Sectioning on Residual Stresses in Aluminum AA7749 Friction Stir Welds[J].Materials Science and Engineering:A,2008,488(1/2):16-24.