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Yansong Zhang - One of the best experts on this subject based on the ideXlab platform.

  • effect of Electrode Force on expulsion in resistance spot welding with initial gap
    Materials Science Forum, 2011
    Co-Authors: J Shen, Yansong Zhang
    Abstract:

    Compared with the conventional low carbon steels, the expulsion is more prone to occur in resistance spot welding (RSW) of dual phase (DP) steels. Especially when the initial gap exists between the steel sheets, the weld expulsion would reduce the weld quality of the joint. It is important to decrease or inhibit the occurrence of the weld expulsion in auto-body assembly line in order to guarantee the joint quality. In this study, the experiments of RSW with different initial gaps have been done to study the effect of the Electrode Force on the expulsion using different thicknesses of dual phase steels. The results show that the increment of the Electrode fore would enable to decrease the occurrence of expulsion with the increase of the sheet thickness and gap spacing in resistance spot welding of DP steel sheets.

  • Investigations on the weldability of high-strength steels sheet to cylindrical tube single-sided spot welding
    The International Journal of Advanced Manufacturing Technology, 2010
    Co-Authors: Honggang Yang, Yansong Zhang, Guanlong Chen
    Abstract:

    With the promotion of weight reduction, hydroformed tubes have been widely used in vehicle construction. Because of different section shapes in hydroformed tubes, sheet to cylindrical tube joining process by single-sided spot welding (SSSW) is proposed in the present paper. However, because of line contact status and low structural stiffness, welding deformation often occurs. As a result, doughnut weld nugget is formed, and welding quality is affected. In this study, the microstructure and microhardness of the doughnut weld nugget are investigated, and the weldability of high-strength steels sheet to cylindrical tube SSSW with different Electrode Force, tube thickness, and radius is explored, respectively, through the analysis of dynamic electrical resistance. Because of special structural characteristics, the weld lobe for sheet to cylindrical tube SSSW is very narrow. Owing to high dynamic resistance, the weld lobe is moved to the left with small Electrode Force or high tube thickness, and the weld lobe is expanded with thick cylindrical tube. With the decrease of tube radius, crack or expulsion easily occurs, and the weld lobe gets narrow. Welding time is also found to be an important parameter, which influences the weldability because proper welding time can enlarge the weld lobe.

  • improvement of resistance spot weldability for dual phase dp600 steels using servo gun
    Journal of Materials Processing Technology, 2009
    Co-Authors: Xiaoyun Zhang, Guanlong Chen, Yansong Zhang
    Abstract:

    Dual-phase (DP) steel is a kind of advanced high-strength steels (AHSS) developed specifically for automotive application due to its excellent formability and better crash absorption than other conventional AHSS. Resistance spot welding (RSW) is the dominant sheet metal joining method in automobile industry, whereas the weldability of dual-phase steel using conventional air gun is not so excellent for the weld lobe diagram under constant Electrode Force is too narrow. However, this disadvantage can be easily overcome by servo gun's Electrode Force control function. This paper mainly relates how to improve weldability of dual-phase steel by adjusting Electrode Force during spot welding process. By modifying the Electrode Force using an orthogonal experimental design method, the result shows that the width of weld lobe diagram of dual-phase steel can be nearly doubled.

  • effect of variable Electrode Force on weld quality in resistance spot welding
    Science and Technology of Welding and Joining, 2007
    Co-Authors: Yansong Zhang, J Shen
    Abstract:

    AbstractResistance spot weldability is defined as the acceptable welding current ranges as determined by the weld lobe in resistance spot welding. Nowadays many studies have focused on the effect of welding current and welding time under constant Electrode Force on the weld quality and weldability. There is little research on the influence of variable Electrode Force on the weld quality and weldability because of the difficulty in controlling variable Electrode Force using pneumatic gun. In the present study, first, the influence of three stages of Electrode Force, including squeeze Force, welding Force and forging Force, on the quality of welds is analysed. Then a design of experiment approach is applied to analyse the influence of the three stages of Electrode Force on welding quality and thus to obtain optimum parameter of variable Electrode Force by controlling the Electrode Force with servo gun. The comparisons of tensile shear strength, nugget size, weld lobe width and wear rate of Electrode tip bet...

  • Research on Weldability for Dual-Phase Steels Using Servo Gun Spot Welding System
    Key Engineering Materials, 2007
    Co-Authors: Xiaoyun Zhang, Yansong Zhang, Guanlong Chen
    Abstract:

    Dual-phase steel is a mixture of ferrite matrix and martensitic islands distributed at grain boundaries with the possible addition of bainite. Its formability, capacity to absorb crash energy, and ability to resist fatigue make it a desirable material for use in the automotive industry to enhance automobile’s strength and reduce its weight. However, the resistance spot weldability of dual-phase steel is sometimes limited by a propensity for weld metal failure due to the welding process. To improve its weldability, a servo gun spot welding system is introduced to control Electrode Force during the welding process. The paper take 1.5mm DP600 steels as an example, experimental data shows that by optimizing Electrode Force during welding process, the width of weld lobe can be enlarged from 0.9kA to 2.1kA and the weldability of dual phase steel is improved greatly.

Chen Guanlong - One of the best experts on this subject based on the ideXlab platform.

  • Application of servoguns to sheet-tube single sided resistance spot welding
    Transactions of the China Welding Institution, 2020
    Co-Authors: Chen Guanlong
    Abstract:

    In sheet-tube single sided resistance spot welding(SSRSW),the welding lobe is very narrow and welding quality is difficult to assure.The application prospects of the controllable characteristic of Electrode position,moving speed and Electrode Force of servoguns were investigated.The research results show that the soft-touch advantage of servoguns can avoid the effect of impact Force on work pieces,and guarantee perfect contact status of the sheet-tube;reductioin of Electrode Force during welding can improve welding quality significantly,and decrease welding deformation and improve welds attribute greatly,and widen the welding lobe by utilizing Electrode Force character of servoguns.Servoguns can provide high assurance for welding quality of sheet-tube SSRSW,and have expansive application prospect in sheet-tube SSRSW.

  • Effect of variable Electrode Force on weld formation of sheet to tube joining with single-sided spot welding
    Transactions of the China Welding Institution, 2020
    Co-Authors: Chen Guanlong
    Abstract:

    An axisymmetric finite element model was established to simulate the nucleation process of sheet-tube single-sided spot welding(SSSW).The temperature distribution could be charted in Electrode and workpieces,the nucleation process and nugget formation had been simulated by the incrementally coupled thermal-electrical-mechanical analysis.The great deformation of workpieces during sheet-to-tube SSSW makes the weld quality unreliable.Servo gun as a new Electrode,which has some merits such as soft touch and variable Electrode during welding process,is greatly suited to SSSW.Based on the characteristics of servo gun,the effect of variable Electrode Force on nugget formation was analyzed.The results indicat that the decrease of Electrode Force during welding process can increase the width of joining,improve the quality of weld with the same welding condition.The solutions can offer the theoretical basis for the wide use of SSSW in auto production.

  • Effect of processinig parameters on sheet-tube indirect spot welding process
    Transactions of the China Welding Institution, 2020
    Co-Authors: Chen Guanlong
    Abstract:

    In sheet-tube indirect spot welding,it is difficult to assure welding quality because the welding deformation is too large.The expansion and welding deformation were investigated and the influence of different welding parameters(welding current,Electrode Force and welding time)on indirect spot welding process was analyzed through Electrode displacement.The experiment result shows that the course of the expansion and welding deformation are coupled to each other in the welding stage;in the holding stage,welding deformation gets larger under the ailion of applied Electrode Force.Maximum welding deformation of sheet-tube indirect spot welding process is almost linear with Electrode Force and input welding energy.Ladder-type occurs in the Electrode displacement curve when the expulsion happens,so the expulsion can be judged according to the slope coefficient of Electrode displacement.The result provides a theoretical guidance for on-line monitoning and control of welding quality in sheet-tube indirect spot welding process.

  • quality of resistance spot welding based on variable Electrode Force
    Transactions of the China Welding Institution, 2008
    Co-Authors: Chen Guanlong
    Abstract:

    Hot dipped galvanized(HDG) low carbon steels have been widely used in internal and outside plates of auto body.Constant Electrode Force was utilized under conventional pneumatic guns,which led to unstable welding quality.However,the quality of resistance spot welding(RSW) on galvanized steels was sensitive to variable Electrode Force.Considering controlling Electrode Force exactly with servo guns,a design of experiment(DOE) method was applied to analyze the influence of three stages of Electrode Force during the welding process,including preliminary Force,welding Force and forging Force,on welding quality and to obtain optimum parameters of variable Electrode Force.The results showed that forging Force was noted as the most important factor,welding Force as secondary one,squeeze Force as least important one,and that optimum parameters could increase tensile-shear Force and nugget diameter of welds significantly.This method would be the foundation of real-time quality evaluation and control based on Electrode Force.

Nizamettin Kahraman - One of the best experts on this subject based on the ideXlab platform.

  • The effects of Electrode Force, welding current and welding time on the resistance spot weldability of pure titanium
    The International Journal of Advanced Manufacturing Technology, 2012
    Co-Authors: Yakup Kaya, Nizamettin Kahraman
    Abstract:

    In this study, commercially pure titanium sheets (American Society for Testing and Materials grade 2) were welded by resistance spot welding at various welding parameters. The welded joints were subjected to tensile-shearing tests in order to determine the strength values. In addition, the hardness and microstructural examinations were carried out in order to examine the influence of welding parameters on the welded joints. The experimental results showed that increasing Electrode Force, welding current and welding time increased the tensile-shearing strength of the welded specimens. Hardness measurement results indicated that welding nugget had the highest hardness and this was followed by the heat-affected zone and the base metal. Microstructural examinations showed the growth of the weld nugget grains with increasing heat input. Besides, due to plastic deformation during the welding process, twins were formed and at the same time twins increased with increasing Electrode Force, welding current and welding time.

  • the influence of welding parameters on the joint strength of resistance spot welded titanium sheets
    Materials & Design, 2007
    Co-Authors: Nizamettin Kahraman
    Abstract:

    In this study, commercially pure (CP) titanium sheets (ASTM Grade 2) were welded by resistance spot welding at different welding parameters and under different welding environments. The welded joints were subjected to tensile-shearing tests in order to determine the strength of the welded zones. In addition, hardness and microstructural examinations were carried out in order to examine the influence of welding parameters on the welded joints. The results showed that increasing current time and Electrode Force increased the tensile shearing strength and the joints obtained under the argon atmosphere gave better tensile-shearing strength. Hardness measurement results indicated that welding nugget gave the highest hardness and the heat affected zone (HAZ) and the base metal followed this. The argon gas used during the welding process was seen to have no influence on the hardness values. Microstructural examinations revealed that the deformations took place in the welding zone during welding. The twinning took place in the grains. High Electrode Force and high weld cycles, were used during the welding, increased the twinning.

Guanlong Chen - One of the best experts on this subject based on the ideXlab platform.

  • Investigations on the weldability of high-strength steels sheet to cylindrical tube single-sided spot welding
    The International Journal of Advanced Manufacturing Technology, 2010
    Co-Authors: Honggang Yang, Yansong Zhang, Guanlong Chen
    Abstract:

    With the promotion of weight reduction, hydroformed tubes have been widely used in vehicle construction. Because of different section shapes in hydroformed tubes, sheet to cylindrical tube joining process by single-sided spot welding (SSSW) is proposed in the present paper. However, because of line contact status and low structural stiffness, welding deformation often occurs. As a result, doughnut weld nugget is formed, and welding quality is affected. In this study, the microstructure and microhardness of the doughnut weld nugget are investigated, and the weldability of high-strength steels sheet to cylindrical tube SSSW with different Electrode Force, tube thickness, and radius is explored, respectively, through the analysis of dynamic electrical resistance. Because of special structural characteristics, the weld lobe for sheet to cylindrical tube SSSW is very narrow. Owing to high dynamic resistance, the weld lobe is moved to the left with small Electrode Force or high tube thickness, and the weld lobe is expanded with thick cylindrical tube. With the decrease of tube radius, crack or expulsion easily occurs, and the weld lobe gets narrow. Welding time is also found to be an important parameter, which influences the weldability because proper welding time can enlarge the weld lobe.

  • improvement of resistance spot weldability for dual phase dp600 steels using servo gun
    Journal of Materials Processing Technology, 2009
    Co-Authors: Xiaoyun Zhang, Guanlong Chen, Yansong Zhang
    Abstract:

    Dual-phase (DP) steel is a kind of advanced high-strength steels (AHSS) developed specifically for automotive application due to its excellent formability and better crash absorption than other conventional AHSS. Resistance spot welding (RSW) is the dominant sheet metal joining method in automobile industry, whereas the weldability of dual-phase steel using conventional air gun is not so excellent for the weld lobe diagram under constant Electrode Force is too narrow. However, this disadvantage can be easily overcome by servo gun's Electrode Force control function. This paper mainly relates how to improve weldability of dual-phase steel by adjusting Electrode Force during spot welding process. By modifying the Electrode Force using an orthogonal experimental design method, the result shows that the width of weld lobe diagram of dual-phase steel can be nearly doubled.

  • Research on Weldability for Dual-Phase Steels Using Servo Gun Spot Welding System
    Key Engineering Materials, 2007
    Co-Authors: Xiaoyun Zhang, Yansong Zhang, Guanlong Chen
    Abstract:

    Dual-phase steel is a mixture of ferrite matrix and martensitic islands distributed at grain boundaries with the possible addition of bainite. Its formability, capacity to absorb crash energy, and ability to resist fatigue make it a desirable material for use in the automotive industry to enhance automobile’s strength and reduce its weight. However, the resistance spot weldability of dual-phase steel is sometimes limited by a propensity for weld metal failure due to the welding process. To improve its weldability, a servo gun spot welding system is introduced to control Electrode Force during the welding process. The paper take 1.5mm DP600 steels as an example, experimental data shows that by optimizing Electrode Force during welding process, the width of weld lobe can be enlarged from 0.9kA to 2.1kA and the weldability of dual phase steel is improved greatly.

Honggang Yang - One of the best experts on this subject based on the ideXlab platform.

  • Notice of Retraction Investigations on sheet to cylindrical tube single-sided spot welding using servo gun
    2010 International Conference on Computer Mechatronics Control and Electronic Engineering, 2010
    Co-Authors: Honggang Yang
    Abstract:

    In order to reduce vehicle weight and improve performance, hydroformed tubes have been widely used in the automobile industry. Sheet to cylindrical tube joining process by single-sided spot welding (SSSW) using servo gun is proposed in the present paper to join the parts. However, welding deformation occurs during welding process and welding quality is affected. The present paper investigated the influence of welding current and Electrode Force on welding deformation and tensile-shear strength by experiments, and the weldability of sheet to cylindrical tube SSSW was determined. It is found that the welding deformation was linearly increased with welding current and Electrode Force. Because of expulsion or cracks caused by large welding deformation, the tensile-shear strength was decreased when high Electrode Force or welding current applied. And the weld lobe determined by experimental results was very narrow. The research results can provide guidelines for process analysis and quality control of sheet to cylindrical tube SSSW.

  • Investigations on the weldability of high-strength steels sheet to cylindrical tube single-sided spot welding
    The International Journal of Advanced Manufacturing Technology, 2010
    Co-Authors: Honggang Yang, Yansong Zhang, Guanlong Chen
    Abstract:

    With the promotion of weight reduction, hydroformed tubes have been widely used in vehicle construction. Because of different section shapes in hydroformed tubes, sheet to cylindrical tube joining process by single-sided spot welding (SSSW) is proposed in the present paper. However, because of line contact status and low structural stiffness, welding deformation often occurs. As a result, doughnut weld nugget is formed, and welding quality is affected. In this study, the microstructure and microhardness of the doughnut weld nugget are investigated, and the weldability of high-strength steels sheet to cylindrical tube SSSW with different Electrode Force, tube thickness, and radius is explored, respectively, through the analysis of dynamic electrical resistance. Because of special structural characteristics, the weld lobe for sheet to cylindrical tube SSSW is very narrow. Owing to high dynamic resistance, the weld lobe is moved to the left with small Electrode Force or high tube thickness, and the weld lobe is expanded with thick cylindrical tube. With the decrease of tube radius, crack or expulsion easily occurs, and the weld lobe gets narrow. Welding time is also found to be an important parameter, which influences the weldability because proper welding time can enlarge the weld lobe.

  • Experimental study of single sided sheet to tube resistance spot welding
    Science and Technology of Welding and Joining, 2007
    Co-Authors: Honggang Yang, S. J. Hu, Yanmeng Zhang, Yongbing Li
    Abstract:

    AbstractTo reduce weight and improve performance, hydroformed tubes are being widely used in automotive structure fabrication and the single sided sheet to tube resistance spot welding (SSRSW) is considered as a feasible method for joining a tube to other parts. However, in the sheet to tube SSRSW process, it is difficult to assure welding quality because of large welding deformation due to a lack of support inside the tube. The present paper investigates the influences of welding parameters, such as Electrode Force and welding current, on the welding deformation and quality of the sheet to tube SSRSW using Electrode displacement and tensile shear tests. The effects of different Electrode Force patterns on the welding quality are investigated utilising the Force characteristics of a servo gun. It is found that the welding deformation is influenced by both the Electrode Force and the welding current, and the tensile shear strength declines with larger Electrode Force and higher welding current. However, th...