共查询到17条相似文献,搜索用时 468 毫秒
1.
2.
提出对电弧施加横向磁场的方法,通过偏转电弧改变焊缝两侧电弧热分配,从而提升焊缝成形质量.为了掌握外加横向磁场对电弧热输入分配的影响机制,开展了GTAW电弧热输入分配规律研究;建立了外加横向磁场下的异种钢角焊缝GTAW电弧-熔池耦合瞬态三维模型,对电弧温度场、电磁场、流场开展了耦合计算;对比分析了偏转焊枪与外加横向磁场偏转电弧两种电弧热量分配方式;在上述工作的基础上,研究了外加横向磁场偏转电弧方式磁感应强度对熔透形态和电弧热分配的影响规律.结果表明,偏转焊枪方式在角焊中适应性较差,而外加横向磁场偏转电弧可获得更好的焊接质量.相关研究可为此类异种钢角焊的焊接工艺参数优化提供技术支持. 相似文献
3.
在熔化极气体保护焊过程中,采用大送丝速度,增大焊接电流和焊丝伸出长度是提高焊接熔敷率的直接途径.但当熔滴过渡转变为旋转射流过渡时,电弧不稳,飞溅增大,焊缝成形变差.施加不同频率的纵向交变磁场,对焊缝成形进行控制.采用高速摄像技术,拍摄焊接过程中的电弧形态和熔滴过渡,研究不同频率的磁场对熔滴过渡和焊接飞溅率的影响规律.结果表明,熔滴过渡形式不同,产生飞溅的机理不同;外加频率为1 000 Hz纵向交变磁场时,电弧的旋转半径减小,电弧的挺度增大,旋转射流过渡时电弧更稳定,焊接飞溅率降低,焊缝成形改善. 相似文献
4.
外加磁场对镁合金焊缝组织与裂纹影响机制的研究 总被引:2,自引:0,他引:2
以AZ31B镁合金为研究对象,采用TIG焊接方法,研究了外加纵向磁场对镁合金焊缝成形、焊缝组织及其焊接裂纹的影响规律.研究表明:在外加脉冲交变纵向磁场作用下,镁合金焊缝的熔宽增大,熔深减小,焊缝晶粒细化,析出相增加并呈弥散化分布状况;外加磁场影响了镁合金的焊缝成形和显微硬度,能够控制镁合金焊缝组织、减少镁合金焊缝热裂纹的产生,改善镁合金焊缝的性能. 相似文献
5.
交变纵向磁场作用下MIG焊电弧行为研究 总被引:1,自引:0,他引:1
为了研究交变纵向磁场作用下MIG焊接电弧的物理特性,提高焊接质量,分析了交变纵向磁场作用下电弧带电粒子的受力情况和运动状态,并利用高速摄像手段研究了交变纵向磁场对电弧形态的影响。结果表明,无外加交变纵向磁场时,自由电弧稳定燃烧,电弧轴线与焊丝轴线相重合;当加入交变纵向磁场时,电弧围绕焊丝轴线做逆时针和顺时针交替变化的旋转运动,电弧轴线偏离焊丝轴线;随着励磁电流的增加,电弧的旋转半径增大,电弧偏离焊丝轴线的角度增大,电弧烁亮区域面积减小;当励磁电流为30 A时,电弧的最大偏转角度为45°,此时电弧燃烧变得不稳定,甚至息弧,焊接过程不稳定。 相似文献
6.
7.
8.
GTAW外加间歇交变纵向磁场的数值计算及其对焊接行为的影响 总被引:7,自引:0,他引:7
针对奥氏体不锈钢外加纵向磁场的气体保护钨极电弧焊接(GTAW)时,与电极同轴的单个轴对称空心圆柱线圈在双向脉冲矩形励磁电流作用下产生的间歇交变纵向磁场。采用无瑕点单积分磁场的数学模型,对GTAW焊接外加间歇之变纵向磁场进行了数值计算,该方法具有模型简单、计算速度快和精度高等优点,并讨论了该间歇交变纵向磁场的分布、磁场的均匀性及其纵仙分量与径向分量的比率等规律及其对焊接的影响,认为横磁分量将削弱GT 相似文献
9.
10.
采用钨极氩弧焊(GTAW)方法焊接AZ31镁合金,并在焊接过程引入纵向交流磁场.焊后,检测不同参数下焊接接头的成形系数、拉伸性能和硬度,并对显微组织进行分析,研究磁场参数对焊接接头成形特点及组织性能的作用规律.结果表明,外加纵向交流磁场通过改变电弧和熔池的运动状态,使熔池的散热及结晶条件得到改变,使焊缝的成形系数变大,焊缝的显微组织得到细化,力学性能得到提高.当磁场电流为2.0A,磁场频率为20 Hz时,焊接接头的力学性能达到最佳值,其中抗拉强度为231MPa,断后伸长率为11.5%,断面收缩率为14.8%,硬度(HV)为14.40 MPa,焊缝成形系数为4.06,强硬比为16.04. 相似文献
11.
罗键 《中国有色金属学会会刊》2001,(3)
1 INTRODUCTIONElectromagneticstirring (EMS)weldingtech niqueisdifferentfromthecommonarcweldingtech niqueandhasthefollowingadvantages[1~ 3] :1)lowcostsforinvestmentowingtosimpleadditionalequip ment;2 )operationalreliabilitywhichthankstotheuseofhigh performancec… 相似文献
12.
14.
In this study, a three-dimensional (3D) finite element model is developed to investigate thermally induced stress field during hybrid laser–gas tungsten arc welding (GTAW) process. In the hybrid welding case, we focus on the GTAW process sharing common molten pool with laser beam and playing an augment role in the hybrid welding system. An experiment-based thermal analysis is performed to obtain the temperature history, which then is applied to the mechanical (stress) analysis. A modified material model is used to consider the influence of face-to-face contact between the top and bottom metal sheets in the thermo-mechanical analysis of welding lap joints. Results show that the normal stress components prevail in the weld zone during hybrid welding process, and maximum thermal stress exceeding the yield point of material exists at the heat affected zone (HAZ) near the weld pool. Increasing the welding speed causes the penetration and width of weld bead to decrease, and the thermal stress concentration at the welded joint is also reduced accordingly. After welding and cooling down, longitudinal tensile stress (SZ) and transverse compressive stress (SX) are retained in the formed weld, and the higher longitudinal compressive stress exists around the weld bead. In addition, a series of experiments are performed to validate the numerical results, and a qualitative agreement is achieved. Compared to the welded joint obtained by GTAW and laser welding alone, the residual stress concentration in the weld joint obtained by hybrid laser–GTAW is the minimal one. 相似文献
15.
16.
A. R. Kohandehghan S. Serajzadeh 《Journal of Materials Engineering and Performance》2012,21(6):892-899
This study concentrates on the effects of weld sequence and welding fixtures on distribution and magnitude of induced arc welding residual stresses built up in butt-joint of Gas Tungsten Arc Welding (GTAW) AA5251 plates. Aluminum plates have been welded under different welding conditions and then, longitudinal and transverse residual stresses were measured in different points of the welded plates employing hole-drilling technique. The results indicate that welding sequence significantly alters the distributions of both longitudinal and transverse residual stresses while the changing in the weld sequence leads to 44% decrease in longitudinal residual stress. Besides, both the geometry of weld pool and distribution of residual stresses are affected by the welding fixtures while implementation of fixture causes about 21 and 76% reductions in the depth of weld pool and transverse residual stress, respectively, for the material and welding conditions used in this research. 相似文献