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Experimental Analysis on the Variable Polarity Plasma arc pressure

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Chinese Journal of Mechanical Engineering 2011年第4期24卷 607-611页

作者： JIANG Yi XU Binshi LUE Yaohui LIU Cunlong LIU Ming National Science and Technology on Remanufacturing Laboratory Academy of Armored Force Engineering Beijing 100072 China Naval FlyingAcademy of China Huludao 125101 China

arc pressure is one of the key factors for variable polarity plasma arc（VPPA） and welding pool formation. In this paper, VPPA pressure is measured by pressure transducer and U-tube barometer methods, and advantages and disadvantages of the two methods are compared. The effects of welding parameters, including with straight polarity（SP） current, reverse polarity（RP） current, time ratio of SP to RP, plasma gas flow rate, on VPPA pressure are investigated by using an orthogonal design. The experimental results indicate that the influencing degree of the welding parameters are in the order of plasma gas flow rate, SP current, time ratio of SP to RP, RP current. These results are important to researches of VPPA welding process and its mechanism. The physics behavior of VPPA is taken into account when the above influence mechanisms are analyzed. Firstly, according to the mechanism of the cooling compression to the arc, the compression to VPPA is enhanced with the increase of plasma gas flow, so the VPPA pressure would increase obviously. Secondly, although the temperature of VPPA is as a function of the welding current, the radius of VPPA is also enhanced. So the effects of SP current on VPPA pressure are inferior to the effects of plasma gas flow. Thirdly, VPPA pressure increases as a function of time ratio of SP to RP because the frequency of welding current influences the arc pressure to the some degree; Finally, the RP intervals are farther less than the SP intervals, so the influence to the pressure is minimal.

关键词： variable polarity plasma arc arc pressure orthogonal experiment

An analytic formula describing the plasma arc pressure distribution

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China Welding 2014年第2期23卷 7-11页

作者： Li Tianqing Wu Chuansong MOE Key Laboratory for Liquid-Solid Structural Evolution and Material Processing and Institute ofMaterial Joining Shandong University Jinan 250061

In plasma arc welding process, the arc force plays a critical role in keyhole formation and weld pool behaviors. The widely used Gaussian mode of the arc pressure just considers the welding current, and other important factors are not involved. Thus, it needs to establish a new formula including the main process parameters. Based on the accelerated plasma impacting theory, a new analytic formula is derived to calculate the plasma arc pressure. It correlates the plasma arc pressure with the main process parameters such as the welding current, arc voltage, plasma gas flow rate, and nozzle size. The detail of the arc pressure derivation is given out. The measured and calculated data of the arc pressure are compared to validate the formula.

关键词： arc pressure arc plasma analytic formula

Influence of arc pressure on the forming of molten pool in tungsten inert gas arc butt welding with micro gap for tantalum sheet

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China Welding 2006年第3期15卷 64-67页

作者：周方明钱乙余 State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Provincial Key Laboratory of Advanced Welding Technology Jiangsu University of Science and Technology Zhenjiang 212003

arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed. Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when butt gap is appropriate, that is from 0. 1 to 0. 15 mm, molten metals formed on two workpiece uplift and grow up first, then are fused and form uniform molten pool finally.

关键词： arc pressure tantalum sheet micro butt gap tungsten inert gas welding mechanism of forming

Experimental Analysis of Welding Parameters on Variable Polarity Plasma arc pressure

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Experimental Analysis of Welding Parameters on Variable Pola...

Gas Pool Coupled Activating TIG Welding Method with Coupling arc Electrode

2012 International Conference on Engineering Materials (ICEM 2012)

作者： Yi Jiang Ming Liu Yaohui Lu Binshi Xu Logistic academy Naval University of Engineering National Science and Technology on Remanufacturing Laboratory Academy of Armored Force Engineering

Variable polarity plasma arc welding has been widely used to manufacture industries. The effects of welding current and plasma gas flow as the most important parameters on variable polarity plasma arc pressure were discussed experimentally. To welding current, two experimental were designed to discuss the effects of straight polarity current and reversed polarity current on arc pressure respectively. It could be concluded that arc pressure is quadratic with welding current. To plasma gas flow, both experimental and numerical analysis are used to discuss the mechanisms of plasma gas flow to arc pressure, and it could be conclude that arc pressure is quadratic with plasma gas flow rather than linear.

关键词： Variable Polarity Plasma arc pressure Welding Current Plasma Gas Flow

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Chinese Journal of Mechanical Engineering 2018年第6期31卷 169-176页

作者： Yong Huang Rui-Lin Liu Yan-Zhao Hao State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of Technology Lanzhou 730050 China Department of Aviation Manufacture Engineering Chengdu Aeronautic Polytechnic Chengdu 610100 China Technology Center Great Wall Motor Company Limited Baoding 071000 China

Gas pool coupled activating TIG(GPCA?TIG) welding put forward in?house can dramatically enhance weld penetration of TIG welding through introducing active element oxygen to reverse the Marangoni convection flow in the molten pool. In order to further improve the welding productivity, the normal solid tungsten electrode is replaced by a kind of coupling arc electrode. The changes of arc pressure distribution along anode surface and the weld appearance were evaluated. On this basis, the dependences of weld shape characterized with weld depth, width and undercut on the main welding parameters were discussed. The results indicate, the substitution of coupling arc electrode can lead to an obvious decrease of arc pressure. Compared to hollow tungsten electrode and twin tungsten electrodes, the coupling arc electrode is much easier to manufacture and has more compacter structure. Combined with the symmetric distribution of arc pressure in di erent directions, this electrode has extensive adaptability. In the GPCA?TIG welding with coupling arc electrode, both the substitution of coupling arc electrode and the introduction of outer active gas oxygen can reduce the possibilities of producing humping bead and undercut. Their joint action makes this welding method have the capability of realizing high travel speed and deep penetration welding.

关键词： GPCA?TIG welding Coupling arc electrode Oxygen arc pressure Weld shape Welding parameter

Modeling of arc Force in Plasma arc Welding

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Transactions of Tianjin University 2008年第3期14卷 157-163页

作者：高忠林胡绳荪殷凤良王睿 School of Material Science and Engineering Tianjin University College of Electrical Engineering and Information Hebei University of Technology

A three-dimensional mathematical model for the transferred-type argon arc was developed to describe arc force on the anode surface. The software ANSYS was employed to solve the model. The model includes a part of torch and tungsten electrode to achieve more reasonable resuits. The arc temperature and flow fields were derived. And the influences of welding parameters on arc force were also studied. The simulated results show that arc pressure at the anode are dependent on the welding current, plasma gas flow rate and electrode neck-in, while not sensitive to arc length.

关键词： plasma arc welding mathematic model ANSYS arc pressure

Characteristics of arc in variable polarity plasma arc welding of aluminum alloy

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China Welding 2014年第3期23卷 73-77页

作者：洪海涛韩永全杜茂华吴永军 College of Materials Science and Engineering Inner Mongolia University of Technology Huhhot 010051.

A double invert variable polarity plasma arc （VPPA） power source based on 16-bit MCU applied for aluminum alloys was developed. Mechanics, electrical and the produced heat mechanism of VPPAW arc were tested and analyzed. Results indicate that during the VPPA welding procedure of aluminum alloy, the arc of electrode negative （EN） has more effect on force, whereas the arc of electrode positive （ EP ） has more effect on heat. It should be noted that keeping the balance of the force and heat is the critical element of VPPAW. This power source had been successfully used to weld aluminum alloy with a 15 mm thickness in vertical welding. The conclusions are applicable to the variable polarity plasma arc welding technique used in the aerospace industry.

关键词： variable polarity plasma arc arc pressure aluminum alloy