The numerical value that configuration of bath of solder of arc of helium of laminose to tantalum to receiving clearance TIG affects is analysed

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Summary: To consider to solder clearance of the butt joint in the process is opposite the influence of bath configuration, the article is based on finite yuan of analytic software ANSYS, in the light of tantalum thin plate arc of helium of small clearance TIG solders method, calculated with numeric simulative method of field of the temperature when clearance of the butt joint in process of butt welding of arc of helium of TIG of tantalum thin plate exists distributing and the change of configuration of surface of the bath when clearance of different butt joint. The metabolic to bath face figure effect that analysed butt joint clearance, the temperature field of center of welding line of deviate of the welding torch when existing to clearance undertook an analysis. Because edge effect is mixed,calculated solder of field of the temperature inside the workpiece when the heat that significant action limits brings heat source delivers effect to differ distributing. The presence that computation indicates clearance as a result causes temperature field to distributing not all, it is bath surface configuration presents a elliptic critical factor, the addition that this kind of influence lets weld time is more apparent. Research result has real direct sense to making TIG solder technology. Foreword Tantalum is a kind of plasticity better, the difficult fuse that makes treatment easily rare metal, apply extensively at the domain such as chemical industry, spaceflight industry, nuclear energy industry and electronic industry [1] . In industrial production, tantalum structural member is to use soldering method to machine normally make, but tantalum is soldering the existence in the process inspiratory, grain is bulky reach easy form the issue such as air hole and crackle [2, 3] , and its special application environment to soldering quality asks very tall, assure to solder so quality makes the task that solves urgently. Existing data shows, of tantalum solder the research of figuration respect still is lacked very much, because this is begun,solder to tantalum the research of craft has real sense. Solder the process is local and fast the process that heats to cool subsequently to high temperature, the temperature of whole weldment changes quickly along with time and space, easy form in the gradient inside time and dimensional territory very big inhomogenous temperature field, the distributinging decision of temperature field is worn welding line area and the limits that heat up influence area, to soldering the quality of contact is having immediate effect. The craft of flat butt welding in real industry, the mechanical error as a result of stationary fixture and a few factitious elements, make butt joint workpiece produces little space extremely easily, and little space is having huge effect to workpiece temperature field. To soldering at present temperature field calculative considers to be confined to unoccupied place butt welding of veneer remelting and very close to each other [4] , and the existence of clearance is an influence welding line figuration and solder a of quality main factor, because this begins the research of this respect,having great sense. 1 computation model and 　 of attrib border condition 1.

The article introduced 1 computation model finite yuan of analytic software ANSYS710, undertook to the model corresponding numerical value changes processing, band of photograph of Surf152 of hypostatic and unit So1id70 and exterior unit was used in computational process, besides bring to bear on the convection of whole and outside comes loose workpiece and clamping apparatus and protective mold still considered outside hot condition between conduct heat. Because of the symmetry of the model, this second computation chose one of butt welding experiment to try only board undertake the model is calculated building. To assure butt joint clearance, special fixture is used to secure work in technical properties experiment at working platform, work measure is the tantalum thin plate of × 015 Mm of 50 Mm of × of 20 Mm. Solder use in experiment process abstain the opposite to protect mold, undertake to workpiece double-faced gas protects: ?  beautifuls; Opposite of 7 L/ Min; of throughput of? of て of  of て  Li protects gas to be argon gas, throughput 5 L/ Min. Solder voltaic I = 75A, solder voltage U = 1714 V, arc length 2 Mm. Be based on ANSYS to get used to reseau to differentiate oneself technology, this second research is used tetrahedral the reseau that is united in wedlock with hexahedral unit photograph differentiates principle, undertake to workpiece and clamping apparatus the reseau of unit appearance differentiates differring. The model uses the method that is not even reseau to come to those who have unit differentiate. If the graph is shown 1 times, seaming area nearly to receiving a face to reach, use relatively close reseau to differentiate, and in be far from welding line area, use rougher reseau to differentiate. So OK precision of computation of give attention to two or morethings and speed. Graph 1 blame is even reseau differentiates type 　 1.

The heat energy of thermal treatment zone of electric arc of form of to load of 2 heat source distributings according to adjacent and actual gauss shape of a distribution, electric arc heats the random inside radius a bit R(x, the heat flow of Y) distributings see pattern (1)[6] . (The: in 1) type? Go? of  of Xing bright You Ren takes 017;U to be; I of electric arc voltage in the article to solder voltaic; RH heats for electric arc stain area radius. 1.

The treats 　 1) to make arc hour initiative condition of 3 attrib border conditions: &In type of Lt;DIV Align=left>T = T0 (2)</DIV> : T is the temperature on workpiece, t0 is initiative temperature room temperature (298 K) . When 2) is calculated, space face of place butt joint is set for convection border, consideration air is when clearance part is current with the butt joint face of workpiece generation convection comes loose hot. Do workpiece and air heat exchange: of convection border condition? The; H of coefficient of thermal conductivity that street? expresses to the λ of temperature gradient; of direction of the random on workpiece is material is the convection coefficient of material. 2 computation result and analytic 　 2.

The influence of clearance of 1 butt joint to field of workpiece surface temperature is opposite to analyse the existence of butt joint clearance the influence of workpiece temperature field, mix for 0109 Mm to clearance clearance is nonexistent 2 kinds of circumstances undertook the model is calculated building, when building a model, part in place of face of workpiece butt joint use convection and conduct 2 kinds of attrib border conditions. Computation makes clear as a result, when having butt joint clearance, bath face figure appears a circle namely figure of face of the bath when clearance of butt joint of wide equal; exists appears X direction and Y direction frit elliptic namely X direction and Y direction frit are wide differ. Because butt joint clearance exists,this is when, hot to receiving the convection of place to come loose rate is slow, make isothermal distributing on X direction closer and distributing on Y direction few and far between, because the frit of this Y direction is wide the frit on X direction is wide, the change that this kind of influence follows weld time is more apparent. Graph the frit on direction of X of 2 watches palpability and Y direction is wide the rule that changes along with weld time. The existence of clearance is an element that bath configuration changes. The computation below 2 kinds of attrib border conditions refers to watch 1 as a result. Watch 1 2 is planted the comparison with the wide frit below attrib border condition pursues butt welding of 2 little space frit is wide along with curve of weld time change (clearance 0.

09 Mm, I =75A, u = 17.

4V) pursues 3 be apart from what equidistance of electric arc center nods to choose a method to pursue different area is apart from what equidistance of electric arc center nods to warm up on 4 workpiece curve (I=75A, u=17.

The influence rule that 4V) 　 distributings to field of the temperature on workpiece to analyse clearance further, the node that went up to choose distance electric arc to add hot center to be 5 Mm with workpiece interior in the butt joint face of clearance respectively, choose methodological sketch map to refer to graph 3. Differ to eliminate clamping apparatus heat conduction to go up to workpiece the influence of positional temperature field, in have without butt joint clearance 2 kinds of circumstances issued the change that to A, B temperature needed a value at 2 o'clock to have consideration, if the metabolic curve that in the A below 2 kinds of conditions inside same time, B the temperature 2 o'clock needs a value pursues 4 are shown. From the graph 4 in can see the effect as a result of clamping apparatus heat conduction, when the temperature 2 o'clock is having A, B to differ value; certainly to exist when clearance, as a result of the influence of clearance, ascendant rate of temperature of face of workpiece butt joint is rapid, and inside same time temperature is worth position of the equidistance inside tower above workpiece a lot of, the temperature difference 2 o'clock is worth A, B relatively when having butt joint clearance, get greatly much. 2.

Clearance of 2 different butt joints is become to the influence of field of workpiece surface temperature two solder board when existence clearance, butt joint board and surroundings generated thermal convection current, took away one part quantity of heat, reduced thereby board inside temperature. The size of butt joint clearance is affecting the significant action range of electric arc directly, soldering the to direction of the X when different clearance and Y direction frit inside clearance limit is wide had consideration, because electric arc is effective,computation makes clear those who follow clearance the change frit bounty of action limits is small as a result greaten and reduce gradually, the frit wide difference of X direction and Y direction follows a butt joint to greaten and increase of clearance, graph the 5 curves that follow change of butt joint clearance for Shi Rongkuan of 0125 S of heat source action. When center of welding line of deviate of welding torch position, make welding line figuration undesirable and the influence solders quality. What answer relatively is reach to issue welding torch position to be received in two pairs without circumstance of butt joint clearance when be apart from face of two butt joints to be 0102 Mm and 0108 Mm respectively for 011 Mm welding torch to clearance accordingly board the temperature field on the workpiece when the identical deviation that go up had consideration, solder the two butt joints after 1s of heat source action board the temperature difference that go up is worth metabolic curve to refer to graph 6. When computation makes clear center of welding line of welding torch deviate as a result, if two board clearance of nonexistent butt joint, because two pairs are received board existence conducts heat exchange strongly, make two board the temperature inside distributings difference is not apparent, when butt joint clearance exists, solder to receiving the edge effect that clearance brings to reach the heat that significant action limits brings heat source delivers effect to differ, make two board on temperature distributinging difference is very big, especially difference of temperature peak value will be bigger, when 0106 Mm of deviate of the welding torch in this second computation, temperature peak value differs a value to have 200 K left and right sides, nevertheless difference of this kind of temperature is in be far from solder heat source point is not obvious. Graph curve of broad change of the frit when 5 different clearance (I=75A, u=17.

4V, t = 0.

25 S) pursues curve of change of the temperature on the workpiece when center of welding line of deviate of 6 welding torch (I = 75A, u = 17.

4V, the article analysed conclusion of T = 1s)3 to differ to solder to receiving clearance to be opposite the influence of temperature field. The model that through soldering craft experiment builds to article place undertook test and verify, the result shows builds model is correct, uses numeric calculation method is feasible, computational result and experimental result close. Get following regular: ? The existence of?) clearance makes temperature field distributings not all, it is bath face figure appears a elliptic critical factor, the addition that this kind of influence lets weld time is more apparent. 2) is in other welder art below the situation with same parameter, the size of butt joint clearance is deciding the significant action limits of electric arc, as butt joint clearance increase frit broad measure to appear reduce a current, and X direction frit is wide reduce a current relatively Y direction is gotten apparently much, this kind of influence makes bath surface configuration elliptical change more apparent. When center of welding line of deviate of 3) welding torch, to receiving the edge effect that clearance brings to make two pairs are received board the temperature difference that go up relatively get greatly when very close to each other is unoccupied place much, make two board on bath size diversity is apparent, create welding line take shape undesirable, this asks in having process of solder of arc of clearance TIG helium welding torch position wants quality solders with assuring in be opposite strictly. CNC Milling