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针对国内船体分段焊接效率和自动化程度低等问题,通过机器人焊接编程,进行了机器人横角焊与立向上角焊工艺试验,分析了机器人焊接主要工艺参数对角焊缝成形的影响。试验结果表明:机器人横角焊时,焊接电流和电弧电压增大,焊缝表面下垂程度增加;对于20 mm厚DH36钢板,在焊接电流280 A和电弧电压27.8 V时,横角焊缝成形良好;机器人立向上角焊时,通过增大电弧梯形摆动幅值有利于增加焊脚长度,但摆动幅值过高易引起咬边缺陷,同时过大的摆动长度使得焊缝表面中心易出现下挂凸起;当电弧摆动幅值5 mm、摆动长度1.5mm、焊接电流200 A、电弧电压24 V左右时,立向上角焊缝成形良好。 相似文献
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窄间隙MAG焊(NG-MAG)过程中电弧摆动和分时熔合技术是保证侧壁熔合良好的关键. 通过对摆动电弧移动过程中速度大小和方向不断变化规律的分析,在经典双椭球热源模型的基础上采用坐标变换法建立了NG-MAG立焊摆动电弧动态热源模型. 温度场模拟结果表明,NG-MAG立焊热循环曲线呈"多峰"现象,焊缝表面成形似"积木"而截面成形似"哑铃",与试验结果基本吻合. 分析认为"多峰"现象主要由电弧热源逐次逼近而后远离所致,而"积木"和"哑铃"的成形特点与移动过程中电弧速度(热输入)的周期变化及焊接熔池的动态变化高度相关,上述热特点对后续进行NG-MAG立焊组织演化研究提供技术支持. 相似文献
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金属丝网衬垫焊剂颗粒工艺对超细颗粒焊剂约束电弧超窄间隙焊缝成形具有重要影响.文中分别采用“V”形、“U”形和“半圆”形三种不同形状金属丝网衬垫焊剂颗粒工艺进行了超窄间隙焊接,并根据所得超窄间隙焊缝横截面形貌,分析了不同形状金属丝网衬垫焊剂颗粒工艺对超窄间隙焊缝成形的影响,以及该工艺防止超窄间隙电弧断续状燃烧的机制.结果表明,随着焊剂对间隙侧壁下方待熔化表面覆盖面积的增大,焊剂熔化对电弧的冷却收缩作用增强,电弧的约束角α减小,以致电弧在侧壁的加热熔化高度hm减小,当hm小于熔化焊丝在超窄间隙内的填充高度时即形成凸焊缝.金属丝网对焊剂颗粒的衬垫有利于电弧阴极斑点在工件待熔化表面快速形成,并加快覆盖在工件待熔化表面区域焊剂颗粒的熔化速度,从而使得电弧阴极斑点区的水平移动速度等于焊丝端头的水平移动速度,以致电弧弧柱未被拉长而连续稳定燃烧. 相似文献
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通过试验研究了坡口角度对电弧形态、熔滴过渡以及电弧信号特征的影响规律.结果表明,坡口角度越小磁偏吹越严重,并引起了熔滴过渡路径和电弧信号的改变.分析了窄坡口P-MAG摆动焊接的信号特征,发现当焊枪摆动中心偏离焊缝中心时,焊枪摆动到左右极限位置时的电弧信号存在明显差异——在焊枪偏向侧壁的一侧,焊枪远离侧壁运动过程中的电弧特征参数变化率远大于焊枪朝向侧壁运动过程电弧参数变化率,而在焊枪远离侧壁的一侧,侧壁位置的电弧参数不存在这种差异.焊枪偏离焊缝中心时在左右极限位置的电弧信号差异可以用来跟踪焊缝中心. 相似文献
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研究摆动电弧窄间隙焊接中的熔滴过渡规律是深入理解该焊接方法的重要基础,由于受到电弧摆动、窄间隙坡口的影响,摆动电弧窄间隙焊接熔滴过渡比常规焊接更加复杂.采用高速摄像系统及焊接电信号采集系统成功地对摆动电弧窄间隙GMAW的熔滴过渡过程进行观测研究,揭示了摆动电弧窄间隙GMAW的熔滴过渡特性,分析了摆动参数、焊接参数对熔滴过渡的影响.结果表明,由于焊丝在坡口之间的摆动改变了焊丝与侧壁之间的距离,引起了焊接电弧长度的变化,促使焊接电流发生了波动,从而导致了摆动电弧窄间隙焊接熔滴过渡的规律性变化. 相似文献
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激光+GMAW复合热源焊接过程热-力耦合数值分析 总被引:3,自引:2,他引:1
从宏观的焊接热过程出发,根据激光+GMAW复合热源焊接的特点,提出了适用于复合热源焊接的“双椭球体+峰值递增圆柱体”组合式体积热源分布模式;建立了激光+GMAW复合热源焊接过程的有限元模型,数值计算了焊接温度场和焊缝横截面的形状尺寸,计算结果与试验结果吻合良好,证明了组合式体积热源模型的合理性和适用性. 采用焊接温度场的计算结果,进一步对复合热源焊接和GMAW的焊接变形和残余应力进行了数值模拟和对比分析. 结果表明,在焊缝熔深基本相同的情况下,复合热源焊接的焊接热输入、焊缝熔宽、焊接变形和高应力区域范围等均比GMAW小. 研究结果印证了激光+GMAW复合热源焊接工艺的优越性,并为焊接工艺参数的优化提供了基础理论数据. 相似文献
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通过试验研究了Nd:YAG激光 脉冲GMAW复合热源焊接过程中焊接工艺参数对焊缝熔宽的影响.结果表明,复合热源焊缝熔宽随电弧功率和激光功率的增大而增大,随焊接速度的提高而减小,而光丝间距和离焦量对复合热源焊缝熔宽影响相对较小.复合热源焊缝熔宽远大于激光焊缝熔宽而仅稍大于脉冲GMAW焊缝熔宽,说明在复合热源焊接过程中脉冲GMAW决定焊缝熔宽,这主要是由于激光束加热区域远小于电弧加热区域造成的.试验结果的分析比较还表明,在激光 电弧复合热源焊接过程中激光功率的增大还极大地提高了焊接速度. 相似文献
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将超细颗粒焊剂约束电弧超窄间隙焊接用于1Cr18Ni9Ti奥氏体不锈钢,通过改变焊接速度、电弧电压、焊接电流对焊缝成形进行了研究.结果表明,在热输入为1.75 kJ/mm和深宽比为1.34的条件下,也不易形成"梨形"焊道裂纹,并且单道焊接时熔化焊丝在超窄间隙内的填充高度可达11.5 mm.在其它焊接参数确定的情况下,随着电弧电压的增加,1Cr18Ni9Ti奥氏体不锈钢超窄间隙焊缝依次呈"凸焊缝"、"凹焊缝"及"电弧攀升"的成形规律.适合于超细颗粒焊剂约束电弧超窄间隙焊接1Cr18Ni9Ti奥氏体不锈钢的电弧电压与焊接电流匹配范围分别约为26~32 V和200~320 A. 相似文献
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《Science & Technology of Welding & Joining》2013,18(2):172-177
AbstractA rotating arc system for narrow gap horizontal welding was developed for solving the problem that the molten pool sagged due to the gravity. The characteristic of the system was that the synchronous rotation of nozzle and wire was generated by eccentric sleeve driven by motor. This process not only may reduce welding effective heat input due to an increase in the welding instantaneous velocity but also may disperse arc force which could counteract the gravity of upper side of molten metal. Both the two aspects were beneficial for horizontal weld formation. Experimental results indicated that shapely horizontal joint could be obtained in appropriate rotating parameters. The asymmetry of joint formation indicated that the heat affected zone width and microstructure in upper side were larger than that in lower side. The effective heat input difference near each side caused by the instantaneous velocity difference was the main reason why the formation characteristics occurred. 相似文献
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《Science & Technology of Welding & Joining》2013,18(8):677-688
AbstractA laser hybrid welding process in which a defocused laser beam is applied beside a gas metal arc weld (GMAW) pool to modify the bead shape was studied. The present paper aims to produce welds with improved toe geometry and better fatigue life than those made with GMAW alone and to apply a numerical simulation to help configure the hybrid process. First, stationary hybrid welds were made to validate weld bead shape predictions and to characterise the spreading of the arc weld deposit to the laser heated spot. Next, the travelling hybrid process was configured with the aid of simulations and fatigue test specimens were welded. Proper application of the laser heat input induced molten metal to spread to the laser heated area, increasing the fillet weld leg length. This produced a larger weld toe angle that decreased the stress concentration and increased the fatigue life of the welds relative to standard mean values. 相似文献
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为了解决镀锌板上锌层易受热烧损,无法使用大电流MIG焊接方法进行高速焊接的问题,采用了一种低热输入高效率的焊接方法——单旁路耦合电弧GMAW(DE-GMAW)用于镀锌板的焊接。搭建了该焊接方法的试验平台,对镀锌板堆焊和搭接接头的高速焊接方法进行试验研究。结果表明,通过调整旁路电流值,单旁路耦合电弧GMAW方法降低了镀锌板上的焊接热输入,并可以在大电流和高焊速的条件下实现镀锌板堆焊和搭接接头的焊接,所得焊缝成形良好,母材变形小,焊接过程稳定无飞溅。焊后镀锌层的烧损与同等热输入条件下的普通MIG焊相比明显降低,保证了镀锌板焊后的耐腐蚀性能。 相似文献
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Radovan Kovacevic 《稀有金属材料与工程》2011,(Z4):102-105
High-strength quenched and tempered (HSQT) steels have been widely used in structural applications where light weight is of primary design interest.Gas metal arc welding is a common way to join QT steels.When GMAW is used to join the HSQT steel,multi-pass is usually required to achieve full penetration.In addition,weld crack is often observed because of HSQT steel’s high susceptibility to hydrogen embrittlement.In addition,due to the large amount of heat input from the arc,the heat affected zone is often softened.This reduces the ductility and strength of welds and makes the weld weaker than the base metal.In this study,a hybrid laser/GMAW process is proposed to produce butt joint for 6.5mm thick HSQT A514 steel plate.Hydrogen diffusion mechanism is first discusses for GMAW and hybrid laser-GMAW welding processes.Metal transfer mode during the hybrid laser/GMAW welding process is also analyzed.A high speed CCD camera with 4000 frame/second is used to monitor the welding process in real time.Welds obtained by GMAW and hybrid laser/GMAW techniques are compared and tested by static lap shear and dynamic impact.Effects of gap between two metal plates and laser beam/GMAW torch spacing on weld property are studied.By appropriately choosing these two parameters,crack-free butt joints with full penetration can be successfully obtained by the hybrid laser/GMAW welding process for HSQT A514 steel plate. 相似文献
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AA-TIG焊(arc assisted activating TIG welding)是一种新型高效焊接方法,该方法通过焊前采用小电流辅助电弧以Ar+O:作为保护气体在待焊部位预熔一道氧化层,然后再进行常规TIG焊,可获得深而窄的焊缝.试验通过改变辅助电弧工艺参数来改变预熔氧化层的厚度,分析预熔氧化层厚度对焊缝成形的影响.结果表明,辅助电弧的电流、速度以及辅助电弧中氧气流量对预熔氧化层厚度有很大的影响,辅助电弧中氧气流量越大、辅助电弧热输入越大时,预熔氧化层越厚;AA—TIG焊时预熔氧化层的厚度对焊缝深宽比影响较大,随着预熔氧化层的增厚,焊缝深宽比先增加后减小. 相似文献