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排序方式: 共有107条查询结果,搜索用时 15 毫秒
1.
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
2.
Based on the high speed video system with electrical signals collecting and wavelet analyzing, the welding processes under three different median currents with the same median time were detected. The experimental results show that, when the median current is higher, the input peak energy is lower. And the droplet transfer is almost in spray mode. The welding process is the stablest. 相似文献
3.
黄勇 《北京工业大学学报》1998,24(3):76-80
根据飞溅机理,对短路液桥收缩过程进行了深入分析和定量描述,指出短路液桥收缩过程规律并对液桥收缩程度进行了实时检测.在此基础上,首次提出了一种恒压与陡降复合的电源外特性,实现了对液桥收缩过程的实时控制,显著地降低了焊接飞溅,取得了优异的工艺效果 相似文献
4.
Formation of small coating droplets is a phenomenon common to spray and roll application of coatings. Generation of small droplets, referred to as atomization, is the mechanism of controlling the quality and thickness of the applied coating layer in spray technology. In roll coating application, small coating droplets are formed at the nip–exit region under certain conditions. Because of the high-shear rates at roll nips and spray nozzles, it is common to relate high-shear viscosity with atomization and roll misting behavior of coatings. This paper will review the relative importance of shear and extensional flows, and the response of coatings to such flows, in affecting misting and atomization behavior. Experimental efforts to quantify the effect of shear and extensional rheological parameters have clearly established a lack of correlation of high-shear viscosities with both spray atomization and roll misting behavior of coatings. However, extensional viscosity is shown to have a strong correlation. Finally, how rheology modifiers can be selected to circumvent misting problems in roll coating applications and atomization problems in spray applications is discussed. 相似文献
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Lü Xiaoqing Cao Biao Zeng Min Huang Zenghao College of Mechanical Engineering South China University of Technology Guangzhou . 《中国焊接》2005,(2)
0IntroductionThe spatter in GMAW-S process is mainly caused byrapid heating of the melted liquid bridge between the weldpool and the electrode during droplet transfer phase or byfailure of arc reignition.To reduce spatter,the early effortwas to control th… 相似文献
7.
文中介绍嘉兴发电厂为了节能降耗,对水力排渣系统的高压水泵进行变频改造。阐述高压变频器的具体方案、选型和变频原理,并分析应用高压变频调速产生的经济效益。 相似文献
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Effects of current waveform parameters during droplet transfer on spatter in high speed waveform controlled Short-circuiting GMAW 总被引:2,自引:1,他引:2
Lü Xiaoqing 《中国焊接》2005,14(2):121-124
Aim at improving the stability of the Short-circuiting Gas Metal Arc Welding (GMAW-S) process for the enhanced speed usage, effects of current waveform parameters during short-term on the welding stability have been investigated by experimental method. The welding power source used for the research is an inverter with a special current waveform control. It is shown that the spatter decreases at first then increases with each increase of the low current period, current increase rate and the maximum current limit. The test results are provided for welding of 1 mm and 3 mm mild steel at speed of 1.2 m/min. The stable GMA W-S process under high speed welding condition has been achieved by optimizing the parameters. 相似文献
10.
减小CO2气体保护焊飞溅的研究现状与展望 总被引:3,自引:2,他引:3
简述了CO2短路过渡焊的飞溅机理,主要从改善电源外特性、波形控制、一元化控制、智能控制等方面综述了当前广泛使用的电控方法。随着以新型功率电子器件为基础的逆变技术的发展,智能型的波控方法是当前减小CO2短路过渡焊飞溅的主要电控方法。 相似文献