基于可控电极力的双相钢胶焊熔核质量控制研究
|
摘要
随着车身轻量化和安全性要求的不断提高，先进高强钢（Advanced HighStrength Steel）材料在车身制造中获得更广泛的应用。其中，双相钢（Dual-Phasesteel）由于具有高强度、好延伸率和强碰撞吸能等特性，已经成为车身轻量化最具应用前景的高强钢材料。电阻点焊（Spot Welding）技术因其低成本、高效率和易实现自动化等优点，是用于车身焊接装配的主要连接工艺。然而，双相钢由于合金元素的增加，点焊过程中很大的冷却温度梯度，易出现界面撕裂问题。发生界面撕裂的焊点十字拉伸强度将下降约10%，而焊点低周疲劳寿命将下降约25%。韧性胶（Toughened Adhesive）的出现，使得胶粘（Adhesive Bonding）工艺具有高静载和疲劳强度，易于连接异种复合材料，但其在低温或潮湿环境下易发生脆性老化。胶焊（Weld-bonding）作为胶粘和电阻点焊复合连接工艺，综合以上两种连接工艺的优点，已在汽车制造工业领域逐步获得应用。然而，双相钢胶焊过程中飞溅、可焊性窗口狭窄等问题更显突出。飞溅不仅易使熔核出现内部缺陷，还会使胶焊接头强度下降约20%。双相钢胶焊的可焊性窗口宽度低于可接受的最小可焊性窗口宽度（2kA），使得网压波动和电极帽磨损时难于保证熔核质量，焊接鲁棒性变差。究其原因主要在于：胶层流动与熔核传热行为的耦合作用机理复杂，胶焊过程熔核区温度场与力场的协调控制难以平衡。因此，研究双相钢胶焊可焊性窗口狭窄的成因，分析电极力对胶焊熔核形成过程的作用机理，揭示胶焊熔核形成规律以及通过可控电极力来拓宽可焊性窗口，是亟待解决的问题，本文正是在上述背景下开展的研究工作。
基于以上背景，本文主要以双相钢材料为研究对象，对双相钢胶焊的熔核质量进行分析，提出基于可控电极力的方法来解决双相钢胶焊可焊性窗口狭窄问题：首先，进行双相钢胶焊熔核力学性能和微观组织试验研究，对比分析胶层存在对熔核质量的影响，探讨双相钢胶焊可焊性窗口狭窄的成因；在此基础上，建立通电阶段的电极力平衡方程，分析胶层黏附力，研究熔核区域温度场对液态熔核内部压力的影响，建立用于获取液态熔核区域温度场的有限元模型，揭示电极力对胶焊熔核形成过程的作用机理；然后分析预压阶段电极力对钢板之间接触电阻的影响，以及通电阶段电极之间动态电阻的不同区域特点，获取双相钢胶焊的熔核形成规律；最后采用回归分析方法，建立临界电极力与焊接工艺参数之间的关系模型，确定可控电极力策略，并对可控电极力策略进行试验验证。论文旨在通过提出可控电极力方法解决双相钢可焊性窗口狭窄问题的同时，提出新型的胶焊熔核质量控制方法，开展的主要研究工作如下：
（1）胶焊熔核质量试验研究
为探寻双相钢胶焊可焊性窗口狭窄等熔核质量问题，论文介绍双相钢胶焊的工艺过程和特点，通过对比研究双相钢胶焊和点焊熔核的力学性能（包括拉剪力、断裂模式与吸能以及可焊性窗口）和微观组织（包括熔核区微观组织和硬度），以揭示双相钢胶焊可焊性窗口狭窄的成因，并提出采用可控电极力可以有效拓宽可焊性窗口。结果表明：双相钢胶焊熔核在低焊接电流情况下就具有较大的熔核尺寸、拉剪力和吸能，易出现熔核剥离的断裂模式。而在高电流情况下极易发生焊接飞溅，且出现部分界面撕裂断裂模式。飞溅对拉剪力和吸能起到负面影响。这造成了双相钢胶焊的可焊性窗口过于狭窄。在此基础上，通过对电极力进行初步试验研究，结果表明改变电极力可明显改善双相钢胶焊可焊性窗口，为基于可控电极力的双相钢胶焊熔核质量控制提供试验数据支持。
（2）电极力对胶焊熔核形成过程的作用机理分析
为揭示电极力对双相钢胶焊熔核形成过程的作用机理，论文分析电极力对双相钢胶焊工艺过程的影响，采用理论力学和热力学理论，建立通电阶段电极力平衡方程和保持熔核受力平衡的临界电极力计算公式，确定胶层内部黏附力，建立胶焊液态熔核内部压力与熔核区域温度场之间的关系模型，并通过有限元仿真获取胶焊熔核区域的温度场。结果表明：液态熔核受力能否实现平衡，是通电阶段电极力、胶层内部黏附力与液态熔核内部压力的互作用结果。液态熔核内部压力是由双相钢钢板在固、液态的材料属性、液态熔核的半径和厚度以及液态熔核区域的温度场共同决定。这为可控电极力幅值的确定提供理论基础。
（3）基于动态电阻的胶焊熔核形成规律研究
电极力大小决定钢板之间接触电阻分布，同时通电阶段电极之间动态电阻变化可反映熔核形成规律。为此，论文应用接触理论并结合试验研究，分析预压阶段电极力对钢板之间接触电阻的影响，结合熔核区域温度场的有限元仿真结果，分析通电阶段电极之间动态电阻的不同区域特点，获取双相钢胶焊的熔核形成规律，对比分析通电阶段双相钢胶焊与点焊的熔核形成过程。结果表明：较大的预压阶段电极力会增加导电斑点的数目和直径，进而降低钢板之间的接触电阻。电极压入位置的绝缘胶层主要影响熔核形成之前的钢板之间接触电阻和接触面积，会使得通电初期的热量积聚速度较快。基于上述分析结果，需在预压和通电阶段之间、通电阶段分别进行电极力调整，可在有效保证胶焊熔核尺寸的同时，降低焊接飞溅的发生。
（4）面向胶焊熔核质量控制的可控电极力策略建立
基于以上理论和试验分析，确定了可控电极力对双相钢胶焊熔核质量的影响规律。为建立双相钢胶焊过程的可控电极力策略，论文采用有限元仿真计算与试验结果对比分析，进行临界电极力计算，分析焊接工艺参数（焊接电流、焊接时间和电极力）对液态熔核的温度场、内部压力以及临界电极力的影响，然后建立保持液态熔核区域受力平衡的临界电极力与焊接工艺参数之间的回归模型，进而确定可控电极力的调整时刻和幅值，最后以1.2mm DP780胶焊为例，从熔核尺寸、动态电阻和可焊性窗口三方面进行可控电极力和恒定电极力的试验结果对比分析。结果表明：在高电流情况下，与恒定电极力相比，可控电极力抑制了焊接飞溅，可使熔核尺寸提高10%，使可焊性窗口拓宽近50%。
通过以上工作，本文对双相钢胶焊的熔核形成过程有了一个比较全面和系统的了解，对双相钢胶焊熔核质量问题及其解决方案进行深入探讨。论文围绕可控电极力方法展开研究，不仅有效改善双相钢胶焊熔核质量波动问题，而且对基于电极力的双相钢胶焊熔核质量控制研究提出了新的研究思路，为双相钢胶焊工艺在汽车制造中的进一步推广，提供理论和试验基础。
The demands for lightweight bodies and high safety requirements have promotedthe widespread use of Advanced High Strength Steels (AHSS) in car bodymanufacturing. Owing to its combination of high strength and ductility, Dual-Phase(DP) steel has become one of the most promising AHSS used in lightweight bodies.Spot welding is the major joining method in car body assembly due to its advantagessuch as low cost, high efficiency and easy automation. However, DP steel added withmore alloying elements causes that the spot welding process has a large coolingtemperature gradient and that the spot-welded DP steel is prone to exhibit the weldinterfacial fracture. It will reduce the cross tension strength by about10%and lowcycle fatigue strength by about25%. The development of toughened adhesive hascontributed to an increasingly important role of adhesive bonding in mechanicalfastening because of its high static and fatigue strength, and being convenient forjoining of dissimilar composite materials, etc. However, the adhesive-bondedspecimens are often easily damaged in certain conditions, such as low temperatureand high humidity. Therefore, weld-bonding, a combination of spot welding andadhesive bonding, has been the subject of particular attention in automotive industrysince it displays all the advantages of these two processes. However, some prominentissues occur in the weld-bonded DP steel such as being prone to exhibit the weldexpulsion and a narrow weld lobe. The weld expulsion can not only result in somedefects in the nugget but decrease the joint strength by about20%. The weld lobewidth of the weld-bonded DP steel is lower than the acceptable width,2kA. Adiscrepant weld emerges when welding current fluctuates or electrode caps wearduring welding, which causes a bad robustness in the weld-bonded DP steel. Theunderlying reason is the complicated coupling between the adhesive flow and heattransfer behavior of the weld nugget, and the difficult cooperative control between thetemperature and force field in the nugget region of weld-bonding. Therefore, it is imperative to explain the narrow weld lobe of the weld-bonded DP steel, explore theeffect of the electrode force on the mechanism of the weld-bonded nugget formationand widen the weld lobe through controlled electrode force. This dissertation isconducted under this situation.
Based on the background mentioned above, DP steel is selected as the researchmaterial. The nugget quality of the weld-bonded DP steel is analyzed and thecontrolled electrode force is proposed to settle the narrow weld lobe. Firstly theexperiments about mechanical properties and microstructure of the weld-bondednugget are conducted. The influence of the adhesive layer on the nugget quality isanalyzed to show the underlying reason of the narrow weld lobe in the weld-bondedDP steel. Based on it, the balance equation of the electrode force during weldingstage, the adhesive bonding force and the effect of the temperature field in thenugget region on the force from the liquid nugget are set up. Moreover, a finiteelement model is established to simulate the temperature field in the weld-bondednugget region. The effect of the electrode force on the mechanism of theweld-bonded nugget formation is discovered. Then the effect of the electrode forceduring squeeze stage on the contact resistance between the sheet metals, and thecharacteristics of different regions in the dynamic resistance between electrodesduring welding stage are analyzed in order to discover the mechanism of theweld-bonded nugget formation. Finally using the regression method, the relationshipbetween the critical electrode force and welding parameters is established. Thestrategy of the controlled electrode force is determined and verified throughexperiments. This dissertation is aiming at settling the narrow weld lobe in theweld-bonded DP steel through controlled electrode force and developing a newmethod to control the nugget quality of the weld-bonded DP steel. The main researchis listed as follows.
（1） Experimental study of the weld-bonded nugget quality
In order to explore the narrow weld lobe in the weld-bonded DP steel, thispaper introduces the procedure and characteristic of the weld-bonded DP steel andthen compares mechanical properties (including tensile-shear force, fracture mode, energy absorption and weld lobe) and microstructure (including nuggetmicrostructure and microhardness) of the weld-bonded nugget with those of thespot-welded nugget. The underlying reason of the narrow weld lobe in theweld-bonded DP steel is obtained. It is proposed that the controlled electrode forcecan be used to widen the weld lobe. Results show that the weld-bonded specimenhas a larger nugget size, a higher tensile-shear force and energy absorption, andexhibit the button-pullout fracture more easily at lower welding currents while atrelative higher welding currents weld-bonding is prone to exhibit the weld expulsiontogether with the occurrence of the partial interfacial fracture. The weld expulsionhas a negative influence on the tensile-shear force and energy absorption. Thismakes the weld lobe of the weld-bonded DP steel too narrow. Based on it, thepreliminary experimental results show that the change in the electrode force canimprove the weld lobe in the weld-bonded DP steel, which will provide the datasupport for the research on the nugget quality of the weld-bonded DP steel based oncontrolled electrode force.
（2） Analysis on the effect of the electrode force on the mechanism of theweld-bonded nugget formation
In order to discover the effect of the electrode force on the mechanism of theweld-bonded nugget formation, this paper analyzes the effect of the electrode forceon the process of the weld-bonded DP steel. Through the fundamental mechanicaland thermodynamic analysis, the balance equation of the electrode force duringwelding stage, the formula of the critical electrode force to balance the liquid nuggetformation, the adhesive bonding force and the relational model between the forcefrom the liquid nugget and temperature field in the nugget region are set up.Moreover, a finite element model is established to simulate the temperature field inthe weld-bonded nugget region. Results show that the balanced state is decided bythe interaction between the electrode force during welding stage, the adhesivebonding force and the force from the liquid nugget. The force from the liquid nuggetis determined by material properties of DP steel at solid and liquid state, the radiusand thickness of the liquid nugget, and the temperature field in the nugget region. This will provide the theory basis for determining the amplitude of the controlledelectrode force.
（3） Research on the mechanism of the weld-bonded nugget formation basedon dynamic resistance
The electrode force decides the contact resistance between the sheet metals. Thedynamic resistance between electrodes during welding stage can be used to discoverthe mechanism of the nugget formation. This paper uses the contact theory andexperimental results to investigate the influence of the electrode force on the contactresistance between the sheet metals. With the help of the solutions of the finiteelement model focusing on the temperature field in the weld-bonded nugget region,the characteristics of different regions in the dynamic resistance between electrodesduring welding stage are analyzed in order to discover the mechanism of theweld-bonded nugget formation. The difference of the nugget formation between theweld-bonded and spot-welded DP steel is analyzed. Results show that the higherelectrode force during squeeze stage can increase the amount and diameter of a-spotand thus decrease the contact resistance between the sheet metals. The presence ofthe adhesive layer at the indentation of electrode caps mainly influences the contactresistance and contact area between the sheet metals before the nugget formation.This leads to a large heat produced during the initial welding stage. Based on it, theelectrode force needs to be adjusted between the squeeze and welding stage. Inaddition, the electrode force during welding stage also needs to be adjusted to ensurethe weld-bonded nugget size and avoid the weld expulsion.
（4） Determination of the strategy of the controlled electrode force focusingon controlling the weld-bonded nugget quality
Based on the above theory and experiment analysis, the influence of thecontrolled electrode force on the nugget quality of the weld-bonded DP steel isestablished. In order to determine the strategy of the controlled electrode force in theweld-bonded DP steel, this paper compares the solutions of the finite element modelwith experimental results to calculate the critical electrode force, and thus analyze the effect of the welding parameters (i.e. welding current, welding time and electrodeforce) on the temperature field in the nugget region, the force from the liquid nuggetand the critical electrode force. The relational model between the critical electrodeforce and welding parameters is set up to determine the moment and amplitude ofthe controlled electrode force.1.2mm DP780steel is used to conduct thecomparative experiments using the controlled and constant electrode force in termsof nugget size, dynamic resistance and weld lobe. Results show that the controlledelectrode force can inhibit the weld expulsion and then increase the nugget size byalmost10%at high currents. Moreover, the weld lobe of the weld-bonded DP steel iswidened by almost50%when the controlled electrode force is used.
Based on the contents mentioned above, a general and systemic understandingof the nugget formation of the weld-bonded DP steel is conducted. The issues aboutthe nugget quality of the weld-bonded DP steel and corresponding solutions are fullyinvestigated. This dissertation focuses on controlled electrode force to improve thefluctuation in the nugget quality of the weld-bonded DP steel and develop a newmethod to control the nugget quality of the weld-bonded DP steel based on electrodeforce. It will provide the theory and experiment basis for the further implementationof the weld-bonded DP steel in automobile manufacturing.
基于以上背景，本文主要以双相钢材料为研究对象，对双相钢胶焊的熔核质量进行分析，提出基于可控电极力的方法来解决双相钢胶焊可焊性窗口狭窄问题：首先，进行双相钢胶焊熔核力学性能和微观组织试验研究，对比分析胶层存在对熔核质量的影响，探讨双相钢胶焊可焊性窗口狭窄的成因；在此基础上，建立通电阶段的电极力平衡方程，分析胶层黏附力，研究熔核区域温度场对液态熔核内部压力的影响，建立用于获取液态熔核区域温度场的有限元模型，揭示电极力对胶焊熔核形成过程的作用机理；然后分析预压阶段电极力对钢板之间接触电阻的影响，以及通电阶段电极之间动态电阻的不同区域特点，获取双相钢胶焊的熔核形成规律；最后采用回归分析方法，建立临界电极力与焊接工艺参数之间的关系模型，确定可控电极力策略，并对可控电极力策略进行试验验证。论文旨在通过提出可控电极力方法解决双相钢可焊性窗口狭窄问题的同时，提出新型的胶焊熔核质量控制方法，开展的主要研究工作如下：
（1）胶焊熔核质量试验研究
为探寻双相钢胶焊可焊性窗口狭窄等熔核质量问题，论文介绍双相钢胶焊的工艺过程和特点，通过对比研究双相钢胶焊和点焊熔核的力学性能（包括拉剪力、断裂模式与吸能以及可焊性窗口）和微观组织（包括熔核区微观组织和硬度），以揭示双相钢胶焊可焊性窗口狭窄的成因，并提出采用可控电极力可以有效拓宽可焊性窗口。结果表明：双相钢胶焊熔核在低焊接电流情况下就具有较大的熔核尺寸、拉剪力和吸能，易出现熔核剥离的断裂模式。而在高电流情况下极易发生焊接飞溅，且出现部分界面撕裂断裂模式。飞溅对拉剪力和吸能起到负面影响。这造成了双相钢胶焊的可焊性窗口过于狭窄。在此基础上，通过对电极力进行初步试验研究，结果表明改变电极力可明显改善双相钢胶焊可焊性窗口，为基于可控电极力的双相钢胶焊熔核质量控制提供试验数据支持。
（2）电极力对胶焊熔核形成过程的作用机理分析
为揭示电极力对双相钢胶焊熔核形成过程的作用机理，论文分析电极力对双相钢胶焊工艺过程的影响，采用理论力学和热力学理论，建立通电阶段电极力平衡方程和保持熔核受力平衡的临界电极力计算公式，确定胶层内部黏附力，建立胶焊液态熔核内部压力与熔核区域温度场之间的关系模型，并通过有限元仿真获取胶焊熔核区域的温度场。结果表明：液态熔核受力能否实现平衡，是通电阶段电极力、胶层内部黏附力与液态熔核内部压力的互作用结果。液态熔核内部压力是由双相钢钢板在固、液态的材料属性、液态熔核的半径和厚度以及液态熔核区域的温度场共同决定。这为可控电极力幅值的确定提供理论基础。
（3）基于动态电阻的胶焊熔核形成规律研究
电极力大小决定钢板之间接触电阻分布，同时通电阶段电极之间动态电阻变化可反映熔核形成规律。为此，论文应用接触理论并结合试验研究，分析预压阶段电极力对钢板之间接触电阻的影响，结合熔核区域温度场的有限元仿真结果，分析通电阶段电极之间动态电阻的不同区域特点，获取双相钢胶焊的熔核形成规律，对比分析通电阶段双相钢胶焊与点焊的熔核形成过程。结果表明：较大的预压阶段电极力会增加导电斑点的数目和直径，进而降低钢板之间的接触电阻。电极压入位置的绝缘胶层主要影响熔核形成之前的钢板之间接触电阻和接触面积，会使得通电初期的热量积聚速度较快。基于上述分析结果，需在预压和通电阶段之间、通电阶段分别进行电极力调整，可在有效保证胶焊熔核尺寸的同时，降低焊接飞溅的发生。
（4）面向胶焊熔核质量控制的可控电极力策略建立
基于以上理论和试验分析，确定了可控电极力对双相钢胶焊熔核质量的影响规律。为建立双相钢胶焊过程的可控电极力策略，论文采用有限元仿真计算与试验结果对比分析，进行临界电极力计算，分析焊接工艺参数（焊接电流、焊接时间和电极力）对液态熔核的温度场、内部压力以及临界电极力的影响，然后建立保持液态熔核区域受力平衡的临界电极力与焊接工艺参数之间的回归模型，进而确定可控电极力的调整时刻和幅值，最后以1.2mm DP780胶焊为例，从熔核尺寸、动态电阻和可焊性窗口三方面进行可控电极力和恒定电极力的试验结果对比分析。结果表明：在高电流情况下，与恒定电极力相比，可控电极力抑制了焊接飞溅，可使熔核尺寸提高10%，使可焊性窗口拓宽近50%。
通过以上工作，本文对双相钢胶焊的熔核形成过程有了一个比较全面和系统的了解，对双相钢胶焊熔核质量问题及其解决方案进行深入探讨。论文围绕可控电极力方法展开研究，不仅有效改善双相钢胶焊熔核质量波动问题，而且对基于电极力的双相钢胶焊熔核质量控制研究提出了新的研究思路，为双相钢胶焊工艺在汽车制造中的进一步推广，提供理论和试验基础。
The demands for lightweight bodies and high safety requirements have promotedthe widespread use of Advanced High Strength Steels (AHSS) in car bodymanufacturing. Owing to its combination of high strength and ductility, Dual-Phase(DP) steel has become one of the most promising AHSS used in lightweight bodies.Spot welding is the major joining method in car body assembly due to its advantagessuch as low cost, high efficiency and easy automation. However, DP steel added withmore alloying elements causes that the spot welding process has a large coolingtemperature gradient and that the spot-welded DP steel is prone to exhibit the weldinterfacial fracture. It will reduce the cross tension strength by about10%and lowcycle fatigue strength by about25%. The development of toughened adhesive hascontributed to an increasingly important role of adhesive bonding in mechanicalfastening because of its high static and fatigue strength, and being convenient forjoining of dissimilar composite materials, etc. However, the adhesive-bondedspecimens are often easily damaged in certain conditions, such as low temperatureand high humidity. Therefore, weld-bonding, a combination of spot welding andadhesive bonding, has been the subject of particular attention in automotive industrysince it displays all the advantages of these two processes. However, some prominentissues occur in the weld-bonded DP steel such as being prone to exhibit the weldexpulsion and a narrow weld lobe. The weld expulsion can not only result in somedefects in the nugget but decrease the joint strength by about20%. The weld lobewidth of the weld-bonded DP steel is lower than the acceptable width,2kA. Adiscrepant weld emerges when welding current fluctuates or electrode caps wearduring welding, which causes a bad robustness in the weld-bonded DP steel. Theunderlying reason is the complicated coupling between the adhesive flow and heattransfer behavior of the weld nugget, and the difficult cooperative control between thetemperature and force field in the nugget region of weld-bonding. Therefore, it is imperative to explain the narrow weld lobe of the weld-bonded DP steel, explore theeffect of the electrode force on the mechanism of the weld-bonded nugget formationand widen the weld lobe through controlled electrode force. This dissertation isconducted under this situation.
Based on the background mentioned above, DP steel is selected as the researchmaterial. The nugget quality of the weld-bonded DP steel is analyzed and thecontrolled electrode force is proposed to settle the narrow weld lobe. Firstly theexperiments about mechanical properties and microstructure of the weld-bondednugget are conducted. The influence of the adhesive layer on the nugget quality isanalyzed to show the underlying reason of the narrow weld lobe in the weld-bondedDP steel. Based on it, the balance equation of the electrode force during weldingstage, the adhesive bonding force and the effect of the temperature field in thenugget region on the force from the liquid nugget are set up. Moreover, a finiteelement model is established to simulate the temperature field in the weld-bondednugget region. The effect of the electrode force on the mechanism of theweld-bonded nugget formation is discovered. Then the effect of the electrode forceduring squeeze stage on the contact resistance between the sheet metals, and thecharacteristics of different regions in the dynamic resistance between electrodesduring welding stage are analyzed in order to discover the mechanism of theweld-bonded nugget formation. Finally using the regression method, the relationshipbetween the critical electrode force and welding parameters is established. Thestrategy of the controlled electrode force is determined and verified throughexperiments. This dissertation is aiming at settling the narrow weld lobe in theweld-bonded DP steel through controlled electrode force and developing a newmethod to control the nugget quality of the weld-bonded DP steel. The main researchis listed as follows.
（1） Experimental study of the weld-bonded nugget quality
In order to explore the narrow weld lobe in the weld-bonded DP steel, thispaper introduces the procedure and characteristic of the weld-bonded DP steel andthen compares mechanical properties (including tensile-shear force, fracture mode, energy absorption and weld lobe) and microstructure (including nuggetmicrostructure and microhardness) of the weld-bonded nugget with those of thespot-welded nugget. The underlying reason of the narrow weld lobe in theweld-bonded DP steel is obtained. It is proposed that the controlled electrode forcecan be used to widen the weld lobe. Results show that the weld-bonded specimenhas a larger nugget size, a higher tensile-shear force and energy absorption, andexhibit the button-pullout fracture more easily at lower welding currents while atrelative higher welding currents weld-bonding is prone to exhibit the weld expulsiontogether with the occurrence of the partial interfacial fracture. The weld expulsionhas a negative influence on the tensile-shear force and energy absorption. Thismakes the weld lobe of the weld-bonded DP steel too narrow. Based on it, thepreliminary experimental results show that the change in the electrode force canimprove the weld lobe in the weld-bonded DP steel, which will provide the datasupport for the research on the nugget quality of the weld-bonded DP steel based oncontrolled electrode force.
（2） Analysis on the effect of the electrode force on the mechanism of theweld-bonded nugget formation
In order to discover the effect of the electrode force on the mechanism of theweld-bonded nugget formation, this paper analyzes the effect of the electrode forceon the process of the weld-bonded DP steel. Through the fundamental mechanicaland thermodynamic analysis, the balance equation of the electrode force duringwelding stage, the formula of the critical electrode force to balance the liquid nuggetformation, the adhesive bonding force and the relational model between the forcefrom the liquid nugget and temperature field in the nugget region are set up.Moreover, a finite element model is established to simulate the temperature field inthe weld-bonded nugget region. Results show that the balanced state is decided bythe interaction between the electrode force during welding stage, the adhesivebonding force and the force from the liquid nugget. The force from the liquid nuggetis determined by material properties of DP steel at solid and liquid state, the radiusand thickness of the liquid nugget, and the temperature field in the nugget region. This will provide the theory basis for determining the amplitude of the controlledelectrode force.
（3） Research on the mechanism of the weld-bonded nugget formation basedon dynamic resistance
The electrode force decides the contact resistance between the sheet metals. Thedynamic resistance between electrodes during welding stage can be used to discoverthe mechanism of the nugget formation. This paper uses the contact theory andexperimental results to investigate the influence of the electrode force on the contactresistance between the sheet metals. With the help of the solutions of the finiteelement model focusing on the temperature field in the weld-bonded nugget region,the characteristics of different regions in the dynamic resistance between electrodesduring welding stage are analyzed in order to discover the mechanism of theweld-bonded nugget formation. The difference of the nugget formation between theweld-bonded and spot-welded DP steel is analyzed. Results show that the higherelectrode force during squeeze stage can increase the amount and diameter of a-spotand thus decrease the contact resistance between the sheet metals. The presence ofthe adhesive layer at the indentation of electrode caps mainly influences the contactresistance and contact area between the sheet metals before the nugget formation.This leads to a large heat produced during the initial welding stage. Based on it, theelectrode force needs to be adjusted between the squeeze and welding stage. Inaddition, the electrode force during welding stage also needs to be adjusted to ensurethe weld-bonded nugget size and avoid the weld expulsion.
（4） Determination of the strategy of the controlled electrode force focusingon controlling the weld-bonded nugget quality
Based on the above theory and experiment analysis, the influence of thecontrolled electrode force on the nugget quality of the weld-bonded DP steel isestablished. In order to determine the strategy of the controlled electrode force in theweld-bonded DP steel, this paper compares the solutions of the finite element modelwith experimental results to calculate the critical electrode force, and thus analyze the effect of the welding parameters (i.e. welding current, welding time and electrodeforce) on the temperature field in the nugget region, the force from the liquid nuggetand the critical electrode force. The relational model between the critical electrodeforce and welding parameters is set up to determine the moment and amplitude ofthe controlled electrode force.1.2mm DP780steel is used to conduct thecomparative experiments using the controlled and constant electrode force in termsof nugget size, dynamic resistance and weld lobe. Results show that the controlledelectrode force can inhibit the weld expulsion and then increase the nugget size byalmost10%at high currents. Moreover, the weld lobe of the weld-bonded DP steel iswidened by almost50%when the controlled electrode force is used.
Based on the contents mentioned above, a general and systemic understandingof the nugget formation of the weld-bonded DP steel is conducted. The issues aboutthe nugget quality of the weld-bonded DP steel and corresponding solutions are fullyinvestigated. This dissertation focuses on controlled electrode force to improve thefluctuation in the nugget quality of the weld-bonded DP steel and develop a newmethod to control the nugget quality of the weld-bonded DP steel based on electrodeforce. It will provide the theory and experiment basis for the further implementationof the weld-bonded DP steel in automobile manufacturing.
引文
[1].王利,张丕军,陆匠心.宝钢汽车板的开发及应用.特殊钢，2003,24(1):55-56.
[2]. Shi M.F., Thomas G.H., Chen M.X. et al. Formability performance comparison betweendual phase and HSLA steels. Iron and Steelmaker (I and SM),2002,29(3):27-32.
[3]. Oliver S., Jones T.B., Fourlaris G. Dual phase versus TRIP strip steels: Comparison ofdynamic properties for automotive crash performance. Materials Science and Technology,2007,23(4):423-431.
[4]. Nishimoto Akihiro, Hosoya Yoshihiro, Nakaoka Kazuhide. New type of dual-phase steelsheet for automobile outer body panels. Transactions of the Iron and Steel Institute of Japan,1981,21(11):778-782.
[5]. Wei Li, Shaowei Cheng, Hu S. Jack et al. Statistical investigation on resistance spot weldingquality using a two-state, sliding-level experiment. Journal of Manufacturing Science andEngineering,2001,123(3):513-520.
[6]. International Iron and Steel Institute. Committee on Automotive Applications, AdvancedHigh Strength Steel (AHSS) Application Guidelines, Version3
[7]. Zhang Xiaoyun, Zhang Yansong, Chen Guanlong. Research on weldability for Dual-Phasesteels using servo gun spot welding system. Key Engineering Materials,2007,353(3):1597-1600.
[8]. Hilditch T.B., Speer J.G., Matlock D.K. Effect of susceptibility to interfacial fracture onfatigue properties of spot-welded high strength sheet steel. Materials and Design,2007,28(10):2566-2576.
[9]. B. Yan, H. Zhu, SH. Lalam et al. Spot weld fatigue of Dual Phase steels. SAE TechnicalPaper Series,2004-01-0511.
[10].张玉龙.粘接技术手册.北京.中国轻工业出版社.2001.
[11]. Wu Xin, Hao Hongqi. The effect of adhesive curing condition on bonding strength in autobody assembly. Journal of Manufacturing Science and Engineering, Transactions of theASME,2005,127(2):411-419.
[12]. C. Gouri, R. Ramaswamy, K.N. Ninan. Studies on the adhesive properties of solidlastomer-modified novolac epoxy resin. International Journal of Adhesion and Adhesives,2000,20(4):305-314.
[13]. Prashant Kumara, Shishir Tiwaria, R.K. Singhb. Characterization of toughened bondedinterface against fracture and impact loads. International Journal of Adhesion andAdhesives,2005,25(6):527-533.
[14]. Kinloch A.J., Korenberg C.F., Tan K.T. et al. Crack growth in structural adhesive joints inaqueous environments. Journal of Materials Science,2007,42(15):6353-6370.
[15]. MIYOSHI Yasuhiko. State of the art in precoated steel sheet for automotive body materialsin Japan. ISIJ International,1991,31(1):1-10.
[16]. Yong Xia, Qing Zhou, P.C. Wang et al. Development of high-efficiency modeling techniquefor weld-bonded steel joints in vehicle structures-Part I: static experiments and simulations.International Journal of Adhesion and Adhesives,2009,29(4):414-426.
[17]. P.C. Wang, S.K. Chisholm, G. Banas et al. Role of failure mode, resistance spot weld andadhesive on the fatigue behavior of weld-bonded aluminum. Welding Journal,1995,74(2):41s-47s.
[18]. Okita Tomoyoshi, Hosoya Yoshihiro, Nakaoka Kazuhide. Manufacturing process of hotrolled dual phase steel. Journal of the Iron and Steel Institute of Japan,1982,68(9):1313-1322.
[19]. Zhang X.Q., Chen G.L., Zhang Y.S. Characteristics of electrode wear in resistance spotwelding dual-phase steels. Materials and Design,2008,29(1):279-283.
[20]. American Welding Society. Recommended practices for test methods for evaluating theresistance spot welding behavior of automotive sheet steel materials,ANSI/AWS/SAE/D8.9–97, AWS, Miami, ML, USA,1997.
[21]. Gajendra Tawade, Gary Boudreau. Robust schedules for spot welding zinc coatedhigh-strength automotive steels. Great Designs in Steel2004Seminar Presentations,American Iron and Steel Institute.
[22]. Jones T.B. A future for weld-bonding sheet steel. Welding and Metal Fabrication,1978,46(6):415-417,419-420.
[23].刘嘉苓,文慕冰,陈乾惕.双相钢的特征与生产工艺.钢铁研究,1985,3:88-94.
[24].吴宝榕.双相钢-物理和力学冶金,冶金工业出版社.1988.
[25]. ULSAB-AVC Consortium, Technical Transfer Dispatch#6(Body Structure Materials), May26,2001.
[26]. Hu S.J. Stream of variation theory for automotive body assembly. Annals of the CIRP,1997,46(1):1-6.
[27]. Dariusz. Dimensional variation reduction for automotive body assembly. ASME ofmanufacturing review,1995,8(2):139-154.
[28]. Liang Xuan, Li Jun, Peng YingHong. Effect of water quench process on mechanicalproperties of cold rolled dual phase steel microalloyed with niobium. Materials Letters,2008,62(2):327-329.
[29]. Krauss George. Microstructure and performance of carburized steel. Part I: martensite.Advanced Materials and Processes,1995,147(5):40Y-40BB.
[30]. Tomasz Wierzbicki. New research program on fracture of advanced high strength steels(AHSS). The Impact and Crashworthiness Lab, MIT, Aug2006.
[31]. Stijn Donders, Marc Brughmans, Luc Hermans et al. The effect of spot weld failure ondynamic vehicle performance. Sound and Vibration,2005,39(4):16-25.
[32].张小云.双相钢点焊熔核界面撕裂失效机理与控制方法研究.上海交通大学,博士学位论文,2008.
[33]. B. Yan, H. Zhu, SH. Lalam et al. Spot weld fatigue of dual phase steels. SAE TechnicalPaper Series,2004-01-0511.
[34]. Xu J, Zhang YS, Lai XM et al. Experimental investigation of fatigue performance of spotwelded dual phase sheet steels. Science and Technology of Welding and Joining,2008,13(8):726-731.
[35]. M. Marya, X.Q. Gayden. Development of requirements for resistance spot weldingDual-Phase (DP600) steels Part1—the causes of interfacial fracture. Welding Journal,2005,84(11):172s-182s.
[36]. M. Marya, X.Q. Gayden. Development of requirements for resistance spot weldingDual-Phase (DP600) steels Part2—statistical analyses and process maps. Welding Journal,2005,84(12):197s-204s.
[37]. Murali D. Tumuluru. An overview of the resistance spot welding of coated high-strengthdual-phase steels. Sheet Metal Welding Conference XII, Michigan, May,2006:1-7.
[38]. M. Marya, K. Wang, L. G. Hector et al. Tensile-shear forces and fracture modes in singleand multiple weld specimens in dual-phase Steels. Journal of Manufacturing Science andEngineering,2006,128:287-298.
[39]. C. Ma, D.L. Chen, S.D. Bhole et al. Microstructure and fracture characteristics ofspot-welded DP600steel. Materials Science and Engineering: A, In Press, CorrectedProof, Available online14August2007.
[40]. Baldan A. Adhesively-bonded joints and repairs in metallic alloys, polymers and compositematerials: adhesives, adhesion theories and surface pretreatment. Journal of MaterialsScience,2004,39(1):1-49.
[41]. Petrie Edward. Epoxy adhesive formulations. McGraw-Hill Professional,2005.
[42].许波涛.汽车用耐高温结构胶粘剂的研制与应用.西北工业大学,硕士学位论文,2004.
[43]. Baldan A. Adhesively-bonded joints in metallic alloys, polymers and composite materials:Mechanical and environmental durability performance. Journal of Materials Science,2004,39(15):4729-4797.
[44]. S.M.H. Darwish, A. Ghanya. Critical assessment of weld-bonded technologies. Journal ofMaterials Processing Technology,2000,105(3):221-229.
[45]. Arne Melander, Mats Larsson, Hanna Stensio et al. Fatigue performance of weldbondedhigh strength sheet steels tested in arctic, room temperature and tropical environments.International Journal of Adhesion and Adhesives,2000,20(5):415-425.
[46]. B. Johansson, A. Olsson. Current design practice and research on stainless steel structuresin Sweden. Journal of Constructional Steel Research,2000,54(1):3-29.
[47]. S.M. Darwish. Characteristics of weld-bonded commercial aluminum sheets (B.S.1050).International Journal of Adhesion and Adhesives,2003,23(3):169-176.
[48]. V.M.Goncalves, Paulo A. F. Martins. Joining stainless steel parts by means of weldbonding.International Journal of Mechanics and Materials in Design,2006,3(1):91-101.
[49].中国机械工程学会焊接学会.电阻焊(III)专业委员会,电阻焊理论与实践.北京:机械工业出版社,1994.
[50]. S.J. Na, S.W. Park. Theoretical study on electrical and thermal response in resistance spotwelding. Welding Journal,1996,75(8):233s-241s.
[51]. B.H. Chang, Y. Zhou. Numerical study on the effect of electrode force in small-scaleresistance spot welding. Journal of Materials Processing Technology,2003,139(1-3):635-641.
[52]. B.H. Chang, D. Du, B. Sui et al. Effect of forging force on fatigue behavior of spot weldedjoints of aluminum alloy5182. Journal of Manufacturing Science and Engineering,Transactions of the ASME,2007,129(1):95-100.
[53].常保华,都东,岁波.锻压力对铝合金点焊接头疲劳行为的影响.焊接学报,2005,26(8):5-8.
[54]. Roger B. Hirsch, Ronald Leibovitz. The effect of tip force on weld quality and electrode life.Technical Paper-Society of Manufacturing Engineers,1999,210:1-8.
[55]. C.T. Ji, Y. Zhou. Dynamic electrode force and displacement in resistance spot welding ofaluminum. Journal of Manufacturing Science and Engineering, Transactions of the ASME,2004,126(3):605-610.
[56]. Y J Park, H Cho. Quality evaluation by classification of electrode force patterns in theresistance spot welding process using neural networks. Proceedings of the Institution ofMechanical Engineers, Part B: Journal of Engineering Manufacture,2004,218(11):1513-1524.
[57]. H Tang, W Hou, S J Hu. Forging force in resistance spot welding. Proceedings of theInstitution of Mechanical Engineers, Part B: Journal of Engineering Manufacture,2002,216(7):957-968.
[58]. H Tang, W. Hou, S J Hu et al. Force characteristics of resistance spot welding of steels.Welding Journal,2000,79(7):175s-183s.
[59]. Furukawa Kazutoshi, Katoh Mitsuaki, Nishio Kazumasa et al. Relation between weldingconditions and temporal change of electrode force-study on the development of electrodeforce changeable lap resistance spot welding machine and characteristics of welds (report1).Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society,2006,24(1):3-9.
[60]. Furukawa Kazutoshi, Katoh Mitsuaki, Nishio Kazumasa et al. Influence of electrodepressure and welding conditions on the maximum tensile shear load-study on thedevelopment of electrode force changeable lap resistance spot welding machine andcharacteristics of welds (report2). Yosetsu Gakkai Ronbunshu/Quarterly Journal of theJapan Welding Society,2006,24(1):10-16.
[61].梁彩平.管板单面电阻点焊模拟与试验研究.上海交通大学.博士学位论文,2008.
[62].杨洪刚.管板电阻点焊椭圆形熔核形成机理及实时监测方法研究.上海交通大学.博士学位论文,2009.
[63].孙海涛,张延松,陈关龙, P.C. Wang.电极力对双相钢点焊质量影响分析.2009先进焊接与连接学术会议暨第一届焊接高层论坛,2009(1):82-85.
[64]. S.A. Gedeon, E T. Wagar. Resistance spot welding of galvanized steel: part I. materialvariations and process modifications. Metallurgical Transactions B (Process Metallurgy),1986,17(4):879-886.
[65]. S.A. Gedeon, E T. Wagar. Resistance spot welding of galvanized steel: part II. mechanismsof spot weld nugget formation. Metallurgical Transactions B (Process Metallurgy),1986,17(4):887-901.
[66]. Y. CHO, S. RHEE. Primary circuit dynamic resistance monitoring and its application toquality estimation during resistance spot welding. Welding Journal,2002,81(6):104s-111s.
[67]. Wei Li, S. Jack Hu, Jun Ni. On-line quality estimation in resistance spot welding. Journal ofManufacturing Science and Engineering,2000,122:511-512.
[68]. D.F. Farson, J.Z. Chen, K. Ely et al. Monitoring resistance spot nugget size by electrodedisplacement. Journal of Manufacturing Science and Engineering, Transactions of theASME,2004,126(2):391-394
[69]. C. Ma, S.D. Bhole, D. L. Chen et al. Expulsion monitoring in spot welded advanced highstrength automotive steels. Science and Technology of Welding and Joining,2006,11(4):480-487.
[70]. Mahmoud El-Banna1, Dimitar Filev, Ratna Babu Chinnam. Intelligent constant currentcontrol for resistance spot welding.2006IEEE International Conference on Fuzzy Systems,2006:1570-1577.
[71].罗震.铝合金电阻点焊过程质量检测及控制方法的研究.天津大学博士学位论文,2001.
[72]. Taka Takao, Kunishige Kazutoshi, Yamauchi Nobuyuki et al. Hot-rolled steel sheet withexcellent flash weldability for automotive wheel rim use. ISIJ International,1989,29(6):503-510.
[73]. Sprenger Stephan, Kinloch Anthony J., Taylor et al. Making industrial adhesives tougher.European Coatings Journal,2009,3:76-79.
[74]. Kang Byoung Un, Jho Jae Young, Kim Junkyung et al. Effect of molecular weight betweencrosslinks on the fracture behavior of rubber-toughened epoxy adhesives. Journal ofApplied Polymer Science,2001,79(1):38-48.
[75]. Kishi Hajime, Uesawa Kazuhiko, Matsuda Satoshi et al. Adhesive strength and mechanismsof epoxy resins toughened with pre-formed thermoplastic polymer particles. Journal ofAdhesion Science and Technology,2005,19(15):1277-1290.
[76].服部隆行.利用伺服焊枪的自动单侧点焊装置.国外机车车辆工艺,2000,5:15-18.
[77]. Slavick S.A. Using servo gun for automated resistance welding. Welding Journal,1999,7:29-33.
[78].张旭强,陈关龙,张延松等.电阻点焊的伺服焊枪技术特性分析.焊接学报,2005,26(6):60-64.
[79]. Automotive Welding Handbook, Revision Date:11/15/96, General Motors.
[80]. Sun HT, Lai XM, Zhang YS et al. Effect of variable electrode force on weld quality inresistance spot welding. Science and Technology of Welding and Joining,2007,12(8):718-724.
[81]. Hamedi M., Shariatpanahi M., Mansourzadeh A. Optimizing spot welding parameters in asheet metal assembly by neural networks and genetic algorithm. Proceedings of theInstitution of Mechanical Engineers, Part B: Journal of Engineering Manufacture,2007,221(7):1175-1184.
[82]. Santos I.O., Zhang W., Goncalves V.M. et al. Weld-bonding of stainless steel. InternationalJournal of Machine Tools and Manufacture,2004,44:1431-1439.
[83]. Aslanlar S., Ogur A., Ozsarac U. et al. Effect of welding current on mechanical properties ofgalvanized chromided steel sheets in electrical resistance spot welding. Materials andDesign,2007,28(1):2-7.
[84]. M.S. Bzdok. High-strength steel joining technologies project, Automotive LightweightingMaterials, FY2005Progress Report.
[85]. Tumuluru Murali D. Resistance spot welding of coated high-strength dual-phase steels.Welding Journal,2006,85(8):31-37.
[86]. Pouranvari M., Abedi A., Marashi P. Effect of expulsion on peak load and energy absorptionof low carbon steel resistance spot welds. Science and Technology of Welding and Joining,2008,13(1):39-43.
[87]. Tong Wei, Tao Hong, Jiang Xiquan et al. Deformation and fracture of miniature tensile barswith resistance spot weld microstructures: an application of digital image correlation todual-phase steels. Metallurgical and Materials Transactions A: Physical Metallurgy andMaterials Science,2005,36(10):2651-2669.
[88]. Podr aj P., Polajnar I., Diaci J. et al. Influence of welding current shape on expulsion andweld strength of resistance spot welds. Science and Technology of Welding and Joining,2006,11(3):250-254.
[89]. Karci Feramuz, Ka ar Ramazan, Gündüz Süleyman. The effect of process parameter on theproperties of spot welded cold deformed AISI304grade austenitic stainless steel. Journal ofMaterials Processing Technology,2009,209(8):4011-4019.
[90]. Wu K.C. Mechanism of expulsion in weldbonding of anodized aluminum. Welding Journal,1977,56(8):238s-244s.
[91]. H. Zhang. Expulsion and its influence on weld quality. Welding Journal,1999,78(11):373s-380s.
[92]. Wu K.C. Resistance spot welding of high contact-resistance surfaces for weldbonding.Welding Journal,1975,54(12):436s-443s.
[93]. Gould J. An examination of nugget development during spot welding using bothexperimental and analytical techniques. Welding Journal,1987,66(1):1s-10s.
[94]. Hao M., Osman K.A., Boomer D.R. et al. Developments in characterization of resistancespot welding of aluminum. Welding Journal,1996,75(1):1s-6s.
[95]. Vahaviolos S.J., Carlos M.F., Slykhouse S.J. Adaptive spot-weld feedback control loop viaacoustic emission. Materials Evaluation,1981,39(10):1057-1060.
[96]. Browne D.J., Chandler H.W., Evans J.T. et al. Computer simulation of resistance spotwelding in aluminum-part II. Welding Journal,1995,74(12):417s-422s.
[97]. Dickinson, D.W. Franklin J.E., Stanya A. Characterization of spot welding behavior bydynamic electrical parameter monitoring. Welding Journal,1980,59(6):170s-176s.
[98]. Radaj D. Heat effects of welding: temperature field, residual stress, distorsion.Springer-Verlag Berlin Heidelberg, Germany,1992.
[99]. Lide D.R. Handbook of chemistry and physics.1994,74th Edition. CRC Press.
[100]. J. Senkara, H. Zhang, S.J. Hu. Expulsion prediction in resistance spot welding. WeldingJournal,2004,83(4):123s-132s.
[101]. G.R. Archer. Calculation for temperature response in spot welds. Welding Journal,1960,8:327s-330s.
[102]. Jamil A. Khan, Kirk Broach, A.A.S. Arefin Kabir et al. Numerical thermal model ofresistance spot welding in aluminum. Journal of thermophysics and heat transfer,2000,14(1):88-95.
[103].李永兵.感应磁场作用下电阻点焊熔核形成过程研究.上海交通大学,博士学位论文,2005.
[104]. H. Murakawa, Y. Ueda. Mechanical study on the effect of the initial gap upon theweldability of spot weld joint. Transactions of JWRI,1989,18(1):51-58.
[105].龙昕.电阻点焊过程的数值模拟.上海交通大学,博士后学位论文,2000.
[106].张旭强.电阻点焊双相钢的电极失效与电极磨损评价研究.上海交通大学,博士学位论文,2007.
[107].吴万春.电磁场理论.北京:电子工业出版社,1985.
[108]. C.S. Tsai, W.L. Dai. Analysis and development of a real time control methodology inresistance spot welding. Welding research supplement,1991,70(12):339s-351s.
[109]. Rogeon P., Carre P., Costa J. et al. Characterization of electrical contact conditions in spotwelding assemblies. Journal of Materials Processing Technology,2008,195(3):117-124.
[110]. R. Raoelison, A. Fuentes, Ph. Rogeon et al. Effect of coating on interfacial conditions innumerical simulation of resistance spot welding process.5th European Thermal-SciencesConference, Netherlands,2008:1-8.
[111]. Ta-chien Sun. Fundamental study of contact resistance behavior in RSW aluminum. Ph. DDissertation, the Ohio State University,2003.
[112]. Greenwood J. A. Constriction resistance and the real area of contact. British Journal ofApplied Physics,1966,17:1621-1632.
[113]. Thornton P. H., Krause A. R., Davis R. G. Contact resistance in spot welding. WeldingJournal,1996,75(12):402s-421s.
[114]. Holm R. Electric contacts-theory and application.4th edition, Springer-Verlag, Berlin.
[115].吴芝亮.质子交换膜燃料电池接触电阻数学建模与参数分析.天津大学,博士学位论文,2008.
[116].程礼椿.电接触理论及应用.北京：机械工业出版社，1988.
[117]. Chen J.Z., Farson D.F. Electrode displacement measurement dynamics in monitoring ofsmall scale resistance spot welding. Measurement Science and Technology,2004,15(12):2419-2425.
[118]. Ji C.T., Zhou Y. Monitoring of dynamic mechanical parameters in resistance spot welding ofaluminium. Welding in the World,2005,49(1):17-21.
[119]. Mei D.S., Li D.Q., Zhang Z.D et al. On-line monitoring method for electrode invalidationduring spot welding of zinc-coated steel. Materials Science and Engineering A,2009,499(1):279-281.
[120]. D. Dickinson, J. Franklin, A. Stanya. Characterization of spot-welding behavior by dynamicelectrical parameter monitoring. Welding Journal,1980,59(6):170s-176s.
[2]. Shi M.F., Thomas G.H., Chen M.X. et al. Formability performance comparison betweendual phase and HSLA steels. Iron and Steelmaker (I and SM),2002,29(3):27-32.
[3]. Oliver S., Jones T.B., Fourlaris G. Dual phase versus TRIP strip steels: Comparison ofdynamic properties for automotive crash performance. Materials Science and Technology,2007,23(4):423-431.
[4]. Nishimoto Akihiro, Hosoya Yoshihiro, Nakaoka Kazuhide. New type of dual-phase steelsheet for automobile outer body panels. Transactions of the Iron and Steel Institute of Japan,1981,21(11):778-782.
[5]. Wei Li, Shaowei Cheng, Hu S. Jack et al. Statistical investigation on resistance spot weldingquality using a two-state, sliding-level experiment. Journal of Manufacturing Science andEngineering,2001,123(3):513-520.
[6]. International Iron and Steel Institute. Committee on Automotive Applications, AdvancedHigh Strength Steel (AHSS) Application Guidelines, Version3
[7]. Zhang Xiaoyun, Zhang Yansong, Chen Guanlong. Research on weldability for Dual-Phasesteels using servo gun spot welding system. Key Engineering Materials,2007,353(3):1597-1600.
[8]. Hilditch T.B., Speer J.G., Matlock D.K. Effect of susceptibility to interfacial fracture onfatigue properties of spot-welded high strength sheet steel. Materials and Design,2007,28(10):2566-2576.
[9]. B. Yan, H. Zhu, SH. Lalam et al. Spot weld fatigue of Dual Phase steels. SAE TechnicalPaper Series,2004-01-0511.
[10].张玉龙.粘接技术手册.北京.中国轻工业出版社.2001.
[11]. Wu Xin, Hao Hongqi. The effect of adhesive curing condition on bonding strength in autobody assembly. Journal of Manufacturing Science and Engineering, Transactions of theASME,2005,127(2):411-419.
[12]. C. Gouri, R. Ramaswamy, K.N. Ninan. Studies on the adhesive properties of solidlastomer-modified novolac epoxy resin. International Journal of Adhesion and Adhesives,2000,20(4):305-314.
[13]. Prashant Kumara, Shishir Tiwaria, R.K. Singhb. Characterization of toughened bondedinterface against fracture and impact loads. International Journal of Adhesion andAdhesives,2005,25(6):527-533.
[14]. Kinloch A.J., Korenberg C.F., Tan K.T. et al. Crack growth in structural adhesive joints inaqueous environments. Journal of Materials Science,2007,42(15):6353-6370.
[15]. MIYOSHI Yasuhiko. State of the art in precoated steel sheet for automotive body materialsin Japan. ISIJ International,1991,31(1):1-10.
[16]. Yong Xia, Qing Zhou, P.C. Wang et al. Development of high-efficiency modeling techniquefor weld-bonded steel joints in vehicle structures-Part I: static experiments and simulations.International Journal of Adhesion and Adhesives,2009,29(4):414-426.
[17]. P.C. Wang, S.K. Chisholm, G. Banas et al. Role of failure mode, resistance spot weld andadhesive on the fatigue behavior of weld-bonded aluminum. Welding Journal,1995,74(2):41s-47s.
[18]. Okita Tomoyoshi, Hosoya Yoshihiro, Nakaoka Kazuhide. Manufacturing process of hotrolled dual phase steel. Journal of the Iron and Steel Institute of Japan,1982,68(9):1313-1322.
[19]. Zhang X.Q., Chen G.L., Zhang Y.S. Characteristics of electrode wear in resistance spotwelding dual-phase steels. Materials and Design,2008,29(1):279-283.
[20]. American Welding Society. Recommended practices for test methods for evaluating theresistance spot welding behavior of automotive sheet steel materials,ANSI/AWS/SAE/D8.9–97, AWS, Miami, ML, USA,1997.
[21]. Gajendra Tawade, Gary Boudreau. Robust schedules for spot welding zinc coatedhigh-strength automotive steels. Great Designs in Steel2004Seminar Presentations,American Iron and Steel Institute.
[22]. Jones T.B. A future for weld-bonding sheet steel. Welding and Metal Fabrication,1978,46(6):415-417,419-420.
[23].刘嘉苓,文慕冰,陈乾惕.双相钢的特征与生产工艺.钢铁研究,1985,3:88-94.
[24].吴宝榕.双相钢-物理和力学冶金,冶金工业出版社.1988.
[25]. ULSAB-AVC Consortium, Technical Transfer Dispatch#6(Body Structure Materials), May26,2001.
[26]. Hu S.J. Stream of variation theory for automotive body assembly. Annals of the CIRP,1997,46(1):1-6.
[27]. Dariusz. Dimensional variation reduction for automotive body assembly. ASME ofmanufacturing review,1995,8(2):139-154.
[28]. Liang Xuan, Li Jun, Peng YingHong. Effect of water quench process on mechanicalproperties of cold rolled dual phase steel microalloyed with niobium. Materials Letters,2008,62(2):327-329.
[29]. Krauss George. Microstructure and performance of carburized steel. Part I: martensite.Advanced Materials and Processes,1995,147(5):40Y-40BB.
[30]. Tomasz Wierzbicki. New research program on fracture of advanced high strength steels(AHSS). The Impact and Crashworthiness Lab, MIT, Aug2006.
[31]. Stijn Donders, Marc Brughmans, Luc Hermans et al. The effect of spot weld failure ondynamic vehicle performance. Sound and Vibration,2005,39(4):16-25.
[32].张小云.双相钢点焊熔核界面撕裂失效机理与控制方法研究.上海交通大学,博士学位论文,2008.
[33]. B. Yan, H. Zhu, SH. Lalam et al. Spot weld fatigue of dual phase steels. SAE TechnicalPaper Series,2004-01-0511.
[34]. Xu J, Zhang YS, Lai XM et al. Experimental investigation of fatigue performance of spotwelded dual phase sheet steels. Science and Technology of Welding and Joining,2008,13(8):726-731.
[35]. M. Marya, X.Q. Gayden. Development of requirements for resistance spot weldingDual-Phase (DP600) steels Part1—the causes of interfacial fracture. Welding Journal,2005,84(11):172s-182s.
[36]. M. Marya, X.Q. Gayden. Development of requirements for resistance spot weldingDual-Phase (DP600) steels Part2—statistical analyses and process maps. Welding Journal,2005,84(12):197s-204s.
[37]. Murali D. Tumuluru. An overview of the resistance spot welding of coated high-strengthdual-phase steels. Sheet Metal Welding Conference XII, Michigan, May,2006:1-7.
[38]. M. Marya, K. Wang, L. G. Hector et al. Tensile-shear forces and fracture modes in singleand multiple weld specimens in dual-phase Steels. Journal of Manufacturing Science andEngineering,2006,128:287-298.
[39]. C. Ma, D.L. Chen, S.D. Bhole et al. Microstructure and fracture characteristics ofspot-welded DP600steel. Materials Science and Engineering: A, In Press, CorrectedProof, Available online14August2007.
[40]. Baldan A. Adhesively-bonded joints and repairs in metallic alloys, polymers and compositematerials: adhesives, adhesion theories and surface pretreatment. Journal of MaterialsScience,2004,39(1):1-49.
[41]. Petrie Edward. Epoxy adhesive formulations. McGraw-Hill Professional,2005.
[42].许波涛.汽车用耐高温结构胶粘剂的研制与应用.西北工业大学,硕士学位论文,2004.
[43]. Baldan A. Adhesively-bonded joints in metallic alloys, polymers and composite materials:Mechanical and environmental durability performance. Journal of Materials Science,2004,39(15):4729-4797.
[44]. S.M.H. Darwish, A. Ghanya. Critical assessment of weld-bonded technologies. Journal ofMaterials Processing Technology,2000,105(3):221-229.
[45]. Arne Melander, Mats Larsson, Hanna Stensio et al. Fatigue performance of weldbondedhigh strength sheet steels tested in arctic, room temperature and tropical environments.International Journal of Adhesion and Adhesives,2000,20(5):415-425.
[46]. B. Johansson, A. Olsson. Current design practice and research on stainless steel structuresin Sweden. Journal of Constructional Steel Research,2000,54(1):3-29.
[47]. S.M. Darwish. Characteristics of weld-bonded commercial aluminum sheets (B.S.1050).International Journal of Adhesion and Adhesives,2003,23(3):169-176.
[48]. V.M.Goncalves, Paulo A. F. Martins. Joining stainless steel parts by means of weldbonding.International Journal of Mechanics and Materials in Design,2006,3(1):91-101.
[49].中国机械工程学会焊接学会.电阻焊(III)专业委员会,电阻焊理论与实践.北京:机械工业出版社,1994.
[50]. S.J. Na, S.W. Park. Theoretical study on electrical and thermal response in resistance spotwelding. Welding Journal,1996,75(8):233s-241s.
[51]. B.H. Chang, Y. Zhou. Numerical study on the effect of electrode force in small-scaleresistance spot welding. Journal of Materials Processing Technology,2003,139(1-3):635-641.
[52]. B.H. Chang, D. Du, B. Sui et al. Effect of forging force on fatigue behavior of spot weldedjoints of aluminum alloy5182. Journal of Manufacturing Science and Engineering,Transactions of the ASME,2007,129(1):95-100.
[53].常保华,都东,岁波.锻压力对铝合金点焊接头疲劳行为的影响.焊接学报,2005,26(8):5-8.
[54]. Roger B. Hirsch, Ronald Leibovitz. The effect of tip force on weld quality and electrode life.Technical Paper-Society of Manufacturing Engineers,1999,210:1-8.
[55]. C.T. Ji, Y. Zhou. Dynamic electrode force and displacement in resistance spot welding ofaluminum. Journal of Manufacturing Science and Engineering, Transactions of the ASME,2004,126(3):605-610.
[56]. Y J Park, H Cho. Quality evaluation by classification of electrode force patterns in theresistance spot welding process using neural networks. Proceedings of the Institution ofMechanical Engineers, Part B: Journal of Engineering Manufacture,2004,218(11):1513-1524.
[57]. H Tang, W Hou, S J Hu. Forging force in resistance spot welding. Proceedings of theInstitution of Mechanical Engineers, Part B: Journal of Engineering Manufacture,2002,216(7):957-968.
[58]. H Tang, W. Hou, S J Hu et al. Force characteristics of resistance spot welding of steels.Welding Journal,2000,79(7):175s-183s.
[59]. Furukawa Kazutoshi, Katoh Mitsuaki, Nishio Kazumasa et al. Relation between weldingconditions and temporal change of electrode force-study on the development of electrodeforce changeable lap resistance spot welding machine and characteristics of welds (report1).Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society,2006,24(1):3-9.
[60]. Furukawa Kazutoshi, Katoh Mitsuaki, Nishio Kazumasa et al. Influence of electrodepressure and welding conditions on the maximum tensile shear load-study on thedevelopment of electrode force changeable lap resistance spot welding machine andcharacteristics of welds (report2). Yosetsu Gakkai Ronbunshu/Quarterly Journal of theJapan Welding Society,2006,24(1):10-16.
[61].梁彩平.管板单面电阻点焊模拟与试验研究.上海交通大学.博士学位论文,2008.
[62].杨洪刚.管板电阻点焊椭圆形熔核形成机理及实时监测方法研究.上海交通大学.博士学位论文,2009.
[63].孙海涛,张延松,陈关龙, P.C. Wang.电极力对双相钢点焊质量影响分析.2009先进焊接与连接学术会议暨第一届焊接高层论坛,2009(1):82-85.
[64]. S.A. Gedeon, E T. Wagar. Resistance spot welding of galvanized steel: part I. materialvariations and process modifications. Metallurgical Transactions B (Process Metallurgy),1986,17(4):879-886.
[65]. S.A. Gedeon, E T. Wagar. Resistance spot welding of galvanized steel: part II. mechanismsof spot weld nugget formation. Metallurgical Transactions B (Process Metallurgy),1986,17(4):887-901.
[66]. Y. CHO, S. RHEE. Primary circuit dynamic resistance monitoring and its application toquality estimation during resistance spot welding. Welding Journal,2002,81(6):104s-111s.
[67]. Wei Li, S. Jack Hu, Jun Ni. On-line quality estimation in resistance spot welding. Journal ofManufacturing Science and Engineering,2000,122:511-512.
[68]. D.F. Farson, J.Z. Chen, K. Ely et al. Monitoring resistance spot nugget size by electrodedisplacement. Journal of Manufacturing Science and Engineering, Transactions of theASME,2004,126(2):391-394
[69]. C. Ma, S.D. Bhole, D. L. Chen et al. Expulsion monitoring in spot welded advanced highstrength automotive steels. Science and Technology of Welding and Joining,2006,11(4):480-487.
[70]. Mahmoud El-Banna1, Dimitar Filev, Ratna Babu Chinnam. Intelligent constant currentcontrol for resistance spot welding.2006IEEE International Conference on Fuzzy Systems,2006:1570-1577.
[71].罗震.铝合金电阻点焊过程质量检测及控制方法的研究.天津大学博士学位论文,2001.
[72]. Taka Takao, Kunishige Kazutoshi, Yamauchi Nobuyuki et al. Hot-rolled steel sheet withexcellent flash weldability for automotive wheel rim use. ISIJ International,1989,29(6):503-510.
[73]. Sprenger Stephan, Kinloch Anthony J., Taylor et al. Making industrial adhesives tougher.European Coatings Journal,2009,3:76-79.
[74]. Kang Byoung Un, Jho Jae Young, Kim Junkyung et al. Effect of molecular weight betweencrosslinks on the fracture behavior of rubber-toughened epoxy adhesives. Journal ofApplied Polymer Science,2001,79(1):38-48.
[75]. Kishi Hajime, Uesawa Kazuhiko, Matsuda Satoshi et al. Adhesive strength and mechanismsof epoxy resins toughened with pre-formed thermoplastic polymer particles. Journal ofAdhesion Science and Technology,2005,19(15):1277-1290.
[76].服部隆行.利用伺服焊枪的自动单侧点焊装置.国外机车车辆工艺,2000,5:15-18.
[77]. Slavick S.A. Using servo gun for automated resistance welding. Welding Journal,1999,7:29-33.
[78].张旭强,陈关龙,张延松等.电阻点焊的伺服焊枪技术特性分析.焊接学报,2005,26(6):60-64.
[79]. Automotive Welding Handbook, Revision Date:11/15/96, General Motors.
[80]. Sun HT, Lai XM, Zhang YS et al. Effect of variable electrode force on weld quality inresistance spot welding. Science and Technology of Welding and Joining,2007,12(8):718-724.
[81]. Hamedi M., Shariatpanahi M., Mansourzadeh A. Optimizing spot welding parameters in asheet metal assembly by neural networks and genetic algorithm. Proceedings of theInstitution of Mechanical Engineers, Part B: Journal of Engineering Manufacture,2007,221(7):1175-1184.
[82]. Santos I.O., Zhang W., Goncalves V.M. et al. Weld-bonding of stainless steel. InternationalJournal of Machine Tools and Manufacture,2004,44:1431-1439.
[83]. Aslanlar S., Ogur A., Ozsarac U. et al. Effect of welding current on mechanical properties ofgalvanized chromided steel sheets in electrical resistance spot welding. Materials andDesign,2007,28(1):2-7.
[84]. M.S. Bzdok. High-strength steel joining technologies project, Automotive LightweightingMaterials, FY2005Progress Report.
[85]. Tumuluru Murali D. Resistance spot welding of coated high-strength dual-phase steels.Welding Journal,2006,85(8):31-37.
[86]. Pouranvari M., Abedi A., Marashi P. Effect of expulsion on peak load and energy absorptionof low carbon steel resistance spot welds. Science and Technology of Welding and Joining,2008,13(1):39-43.
[87]. Tong Wei, Tao Hong, Jiang Xiquan et al. Deformation and fracture of miniature tensile barswith resistance spot weld microstructures: an application of digital image correlation todual-phase steels. Metallurgical and Materials Transactions A: Physical Metallurgy andMaterials Science,2005,36(10):2651-2669.
[88]. Podr aj P., Polajnar I., Diaci J. et al. Influence of welding current shape on expulsion andweld strength of resistance spot welds. Science and Technology of Welding and Joining,2006,11(3):250-254.
[89]. Karci Feramuz, Ka ar Ramazan, Gündüz Süleyman. The effect of process parameter on theproperties of spot welded cold deformed AISI304grade austenitic stainless steel. Journal ofMaterials Processing Technology,2009,209(8):4011-4019.
[90]. Wu K.C. Mechanism of expulsion in weldbonding of anodized aluminum. Welding Journal,1977,56(8):238s-244s.
[91]. H. Zhang. Expulsion and its influence on weld quality. Welding Journal,1999,78(11):373s-380s.
[92]. Wu K.C. Resistance spot welding of high contact-resistance surfaces for weldbonding.Welding Journal,1975,54(12):436s-443s.
[93]. Gould J. An examination of nugget development during spot welding using bothexperimental and analytical techniques. Welding Journal,1987,66(1):1s-10s.
[94]. Hao M., Osman K.A., Boomer D.R. et al. Developments in characterization of resistancespot welding of aluminum. Welding Journal,1996,75(1):1s-6s.
[95]. Vahaviolos S.J., Carlos M.F., Slykhouse S.J. Adaptive spot-weld feedback control loop viaacoustic emission. Materials Evaluation,1981,39(10):1057-1060.
[96]. Browne D.J., Chandler H.W., Evans J.T. et al. Computer simulation of resistance spotwelding in aluminum-part II. Welding Journal,1995,74(12):417s-422s.
[97]. Dickinson, D.W. Franklin J.E., Stanya A. Characterization of spot welding behavior bydynamic electrical parameter monitoring. Welding Journal,1980,59(6):170s-176s.
[98]. Radaj D. Heat effects of welding: temperature field, residual stress, distorsion.Springer-Verlag Berlin Heidelberg, Germany,1992.
[99]. Lide D.R. Handbook of chemistry and physics.1994,74th Edition. CRC Press.
[100]. J. Senkara, H. Zhang, S.J. Hu. Expulsion prediction in resistance spot welding. WeldingJournal,2004,83(4):123s-132s.
[101]. G.R. Archer. Calculation for temperature response in spot welds. Welding Journal,1960,8:327s-330s.
[102]. Jamil A. Khan, Kirk Broach, A.A.S. Arefin Kabir et al. Numerical thermal model ofresistance spot welding in aluminum. Journal of thermophysics and heat transfer,2000,14(1):88-95.
[103].李永兵.感应磁场作用下电阻点焊熔核形成过程研究.上海交通大学,博士学位论文,2005.
[104]. H. Murakawa, Y. Ueda. Mechanical study on the effect of the initial gap upon theweldability of spot weld joint. Transactions of JWRI,1989,18(1):51-58.
[105].龙昕.电阻点焊过程的数值模拟.上海交通大学,博士后学位论文,2000.
[106].张旭强.电阻点焊双相钢的电极失效与电极磨损评价研究.上海交通大学,博士学位论文,2007.
[107].吴万春.电磁场理论.北京:电子工业出版社,1985.
[108]. C.S. Tsai, W.L. Dai. Analysis and development of a real time control methodology inresistance spot welding. Welding research supplement,1991,70(12):339s-351s.
[109]. Rogeon P., Carre P., Costa J. et al. Characterization of electrical contact conditions in spotwelding assemblies. Journal of Materials Processing Technology,2008,195(3):117-124.
[110]. R. Raoelison, A. Fuentes, Ph. Rogeon et al. Effect of coating on interfacial conditions innumerical simulation of resistance spot welding process.5th European Thermal-SciencesConference, Netherlands,2008:1-8.
[111]. Ta-chien Sun. Fundamental study of contact resistance behavior in RSW aluminum. Ph. DDissertation, the Ohio State University,2003.
[112]. Greenwood J. A. Constriction resistance and the real area of contact. British Journal ofApplied Physics,1966,17:1621-1632.
[113]. Thornton P. H., Krause A. R., Davis R. G. Contact resistance in spot welding. WeldingJournal,1996,75(12):402s-421s.
[114]. Holm R. Electric contacts-theory and application.4th edition, Springer-Verlag, Berlin.
[115].吴芝亮.质子交换膜燃料电池接触电阻数学建模与参数分析.天津大学,博士学位论文,2008.
[116].程礼椿.电接触理论及应用.北京：机械工业出版社，1988.
[117]. Chen J.Z., Farson D.F. Electrode displacement measurement dynamics in monitoring ofsmall scale resistance spot welding. Measurement Science and Technology,2004,15(12):2419-2425.
[118]. Ji C.T., Zhou Y. Monitoring of dynamic mechanical parameters in resistance spot welding ofaluminium. Welding in the World,2005,49(1):17-21.
[119]. Mei D.S., Li D.Q., Zhang Z.D et al. On-line monitoring method for electrode invalidationduring spot welding of zinc-coated steel. Materials Science and Engineering A,2009,499(1):279-281.
[120]. D. Dickinson, J. Franklin, A. Stanya. Characterization of spot-welding behavior by dynamicelectrical parameter monitoring. Welding Journal,1980,59(6):170s-176s.