Stainless steel PA

Summary: Article labor stainless steel plasma arc (PA)- tungsten extremely argon arc (solder of GTA) double-faced arc (the craft characteristic of DSAW) , this craft can increase frit deep, reduce solder postheat to be out of shape, in be being applied to especially thick board solder. Compare with photograph of groovy electric arc, the electric arc in process of double-faced arc solder all got the compression of different level. After keyhole effect is built, the extrude of electric arc report between two welding torch shows downtrend; Electric arc crosses workpiece to undertake heating, improved thermal efficiency; Exterior tension, electric arc blows force and electromagnetism agitate force to all be helpful for obtaining bigger frit deep. Keyword: Plasma of alveolus of double-faced arc solder arc preface solders the technology has decisive place in manufacturing industry, it waits for industrial department to be able to apply extensively in car, shipping, marine, aerospace. Raise solder deliver a child to produce efficiency, reduce manufacturing cost, already became the one big target that welder authors seek, soldering in last few years the domain appeared a lot of new inventions related to this, new skill, double-faced arc welding receives only power source craft is among them [1] . In this process, workpiece does not receive report, solder join of two welding torch at same table however of power source polar, two such electric arc rise with respect to meeting series connection the job. Trial test makes clear, this craft is had increase frit heat of the deep, workpiece after reducing solder is out of shape wait an advantage a moment, in be being applied to especially thick board solder. Article general with stainless steel of 5mm thick 1Cr18Ni9Ti board as solder material, study plasma arc (PA) and arc of tungsten pole argon (GTA) the craft characteristic of the double-faced arc solder that combines, be in with driving its further the project is practical the development of the respect. If the graph is shown 1 times,the test facilities principle of vertical position welding of double-faced electric arc of 1 test facilities and test result PA-GTA pursues. What show in the graph solder power source changes for type of homebred LHME-315 inversion polarity plasma arc welding machine, the experiment uses means of dc constant current, among them, plasma arc welding torch receives positive electrode, welding torch of arc of tungsten pole argon receives negative pole. Two welding torch use two water-cooling device respectively. Solder to rise to load quantity of electric current, reduce tungsten pole to burn caustic speed, the tungsten of welding torch of arc of tungsten pole argon extremely the diameter is chosen 6.

4mm, the tungsten of plasma arc welding torch extremely the diameter chooses 3mm. Graph this task of * of graph of test facilities principle suffers solder of 1 PA-GTA double-faced arc fund of key laboratory of national defence science and technology and fund of scholar of visit of key laboratory of colleges and universities fund a plan the 2 welding line that get to use craft of solder of PA-GTA double-faced arc to solder are macroscopical metallographic photograph, among them, a narrow passage providing the only means of access to a certain place of nozzle of plasma arc welding torch is compared for 2.

8/3.

2, nozzle height 5mm, 3mm shrinks inside tungsten pole, 3mm of GTAW arc length. Graph the 3 welding line that to use groovy and bosseyed plasma arc solder place gets are macroscopical metallographic photograph, the norms dimension of plasma arc welding torch and graph 2 identical. Of two groups of experiments solder speed all is 1.

8mm/s. Can see, soldering identically below normative parameter, use the frit that arc solder obtains groovy and bosseyed plasma to have 1 greatly only.

94mm, 38 what reach workpiece ply only.

8% , and use skill of solderer of PA-GTA double-faced arc quite complete frit shows work, and soldering keyhole effect can be formed in the process, assure welding line quality, its advantage clearly. Graph cross section of welding line of solder of 2 PA-GTA double-faced arc is macroscopical photograph Normal Align=center> (material: 1Cr18Ni9Ti stainless steel, board thick: 5mm, solder electric current: 66A, plasma throughput: 2.

0L/min) graph 3 convention are bosseyed cross section of welding line of plasma arc solder is macroscopical photograph (material: 1Cr18Ni9Ti stainless steel, board thick: 5mm, solder electric current: 66A, plasma throughput: 2.

0L/min) characteristic of craft of solder of 2 PA-GTA double-faced arc 2.

The electric arc characteristic in process of double-faced arc solder is opposite 1 stainless steel stainless steel board when using solder of PA-GTA double-faced arc, can use technology of dc constant current and build stable keyhole effect. Once stability of alveolus solder process is built, solder the physical phenomenon that appears in the process will with groovy plasma arc alveolus solder is different, because there still is a welding torch to be in in the other a side of workpiece,act well, such soldering electric arc will get farther compression, electric arc energy also can get further gather, thereby can one-time solder appears thicker test specimen, raise yield of solder deliver a child. Graph 4 with the graph 5 medium electric arc photographs solder to differ namely the plan of electric arc configuration that films in craft. Can see from inside the graph, the tungsten with convention extremely argon arc and plasma arc photograph are compared, the tungsten in process of solder of PA-GTA double-faced arc extremely argon arc and plasma arc more concentration, dimension of electric arc cross section wants relatively small, density of electric arc energy is higher, to obtain bigger frit deep offerred a condition. Normal TEXT-ALIGN in solder of double-faced arc of Center" Align=center>a) groovy GTAb) : Configuration of 4 GTA of Center" Align=center> graph pursues quite (solder electric current: 30A, arc length: 4mm) Normal TEXT-ALIGN in solder of double-faced arc of 0pt" Align=center>a) groovy PAb) : Configuration of 5 PA of Center" Align=center> graph pursues quite (solder electric current: 30A, nozzle height: 5Mm) Normal > pursues 6 with the graph 7 those who show is to be in process of solder of PA-GTA double-faced arc, keyhole effect builds the GTA of around and PA photograph to compare. The B) when A) did not form alveolus just formed the Normal Align=center>c) stabilizes the Normal TEXT-ALIGN of of quarter GTA configuration plan when Center" Align=center> plan differs in process of 6 double-faced arc welding: Center" Align=center>(solders electric current: 66A, protect throughput: 12L/min, solder speed: 1.

The B) when 8mm/s) A) did not form alveolus just formed the Normal Align=center>c) stabilizes the Normal TEXT-ALIGN of of quarter PA configuration plan when Center" Align=center> plan differs in process of 7 double-faced arc welding: Center" Align=center>(solders electric current: 66A, ionic throughput: 2.

2L/min, solder speed: 1.

8mm/s) can observe from inside the graph, after keyhole effect is built, the arc column of arc of tungsten pole argon has a branch to cross alveolus, because arc of tungsten pole argon compares disperse the internal heat with sudorifics relatively, because this still has one part electric arc,still meet action is in workpiece surface. And plasma arc is different, when forming alveolus, complete action is in plasma arc workpiece surface, after alveolus is formed, because plasma arc column is original narrower, the tungsten that will cross other a side of alveolus and workpiece completely because of the much of this arc column extremely argon arc series connection rises, form a long electric arc. Accordingly, after keyhole effect is built, electric arc is right of workpiece heat the form also appeared to change, later development will be discussed in detail. 2.

2 stainless steel are double-faced Normal > is opposite stainless steel board in the process that uses solder of alveolus of PA-GTA double-faced electric arc, when alveolus is built, the data that arrives from electric current and voltage sensor earning shows, solder electric current is constant, and solder voltage -- namely the electric arc voltage between two welding torch appeared to drop, the data that collects sees a picture 8 (graph slightly) be shown. Can see from inside the graph, tungsten of two welding torch extremely the electric arc voltage between drops to be controlled to the 26 ～ 27V after forming alveolus by the 30V before forming alveolus, voltage value fell to make an appointment with 3 ~ 4V, the test result of this one result and Zhang Yuming also is consistent [2] . Solder electric current keeps changeless, solder voltage drops the is power source as a result directly power output of 3 ～ 4V fell, electric arc inputted a quantity to drop to the heat of workpiece 11.

7 ％ , be helpful for reducing workpiece solder postheat to be out of shape thereby, already managing the sources of energy, can improve welding line quality again. (1) electric arc adds the characteristic Normal > electric arc affects the heat on workpiece to input directly. In groovy arc solder in process, a dispersive hair in electric arc energy arrived in surroundings. In process of solder of PA-GTA double-faced arc, after alveolus is built, workpiece the electric arc that two electric arc of two side become a perforative and whole work with respect to series connection, at this moment electric arc is right of workpiece heat kind produced marked change. When forming alveolus, plasma arc is mixed arc of tungsten pole argon parts to undertake heating to workpiece from the two side surface of workpiece, have the part carrying a department of electric arc and workpiece contact only at this moment, a lot of energy of electric arc were not absorbed by workpiece, send out however in surroundings. After forming alveolus, two electric arc are an organic whole repeatedly, form the electric arc of a perforative workpiece, at this moment the electric arc that workpiece will cross bath is whole surround, so can more electric arc energy are absorbed by workpiece, improved electric arc thermal efficiency. Be opposite with the electric arc when having alveolus without alveolus of workpiece heat if means pursues 9 (graph slightly) be shown. (2) electric arc blows the action Normal > is soldering in the process, plasma air current affects the final quality of the flow of liquid state metal and welding line directly to the wallop of bath, to plasma jet force measure and the analysis also sees more in document [3] . In process of solder of PA-GTA double-faced arc, below the circumstance that exists without alveolus, electric arc blows force to produce gas in bath surface shearing force, if pursue 10 (graph slightly) be shown. After occurrence alveolus, electric arc blows force besides it is beyond shearing force of gas of bath surface generation, still meet in the liquid state metal of alveolus interior free surface produces another shearing force, produce an effect to the flow of bath fluid, the liquid state metal that makes workpiece appearance flows to alveolus center, if pursue 11 (graph slightly) be shown. The effect that electric arc plays force also can add welding line the width of intermediate place, be helpful for forming good welding line quality. (The action Normal > is in all driving force that to soldering bath generation affects, the action of exterior tension is the most remarkable. Will tell commonly, the size of exterior tension and direction decide the size at exterior tension temperature coefficient and symbol, when exterior tension temperature coefficient is negative worth, exterior tension will make metal of bath surface liquid flow to bath brim by bath center, form wide and shallow welding line thereby; Should be when be worth, exterior tension will make bath liquid metal flow to bath center by bath brim, form narrow and dark welding line thereby [4] . Normal > is in in process of solder of PA-GTA double-faced arc after occurrence alveolus, exterior tension produces effect besides the liquid state metal to workpiece surface beyond, free to the bath of alveolus wall surface also can produce effect, if pursue,11 are shown. The bath in alveolus wall is free apparently, liquid metal suffers exterior tension, electric arc to play the effect of the driving force such as force, electromagnetism force and flotage, its flow form is more complex. Normal > from the graph 11 (graph slightly) can see, the freedom in bath interior apparently, metal of liquid state of exterior tension drive flows to workpiece interior, when bath the liquid state metal of two side surface layer all comes to internal flow confluent when, liquid state metal is met develop to bath width direction, form wider bond in workpiece interior thereby, added welding line the width of intermediate place, be helpful for forming bigger frit to be mixed greatly good welding line quality. (The action Normal > is soldering in the process, because solder,the Fm of electromagnetism agitate force of bath interior is of electric current and its induction magnetic field interaction and of generation, it drives bath fluid to develop to bath deepness direction, be helpful for obtaining deep and narrow welding line, if pursue 10 (graph slightly) be shown. In process of solder of PA-GTA double-faced arc, as a result of the guiding of two welding torch to two electric arc action, make arc of tungsten pole argon and plasma arc opposite at groovy electric arc more concentration, this will increase electromagnetism agitate power greatly, to increase frit deep offer advantage. And, because in workpiece two side all have electric arc to exist, compare with photograph of groovy arc solder, the electromagnetism agitate power in process of double-faced arc solder is more great to the action of bath, can obtain bigger frit deep. Normal TEXT-INDENT of Exactly">3 brief summary: 21pt; LINE-HEIGHT: 16pt; Mso-char-indent-count: 2.

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5pt; Mso-line-height-rule: Exactly"> (1) compare with photograph of craft of groovy arc solder, craft of solder of PA-GTA double-faced arc can increase frit significantly deep, reduce solder postheat to be out of shape, in be being applied to especially thick board solder. Normal > (2) compare with photograph of groovy electric arc, the electric arc in process of double-faced arc solder all got compression. After keyhole effect is built, the extrude of electric arc report between two welding torch shows downtrend. Normal > (3) in process of solder of alveolus of PA-GTA double-faced electric arc, electric arc crosses workpiece to undertake heating, improved electric arc thermal efficiency; Exterior tension, electric arc blows force and electromagnetism agitate force to all be helpful for obtaining bigger frit deep. CNC Milling