Summary: The weldability that analysed pure nickel can reach its influencing factor. Combine the application in real work, in the light of industry the tubal material of pure nickel solders craft undertakes discussing. solder of arc of tungsten pole argon (Tig solder) use on the foundation abstain argon to enrage protective cover to avoid nickel soldering the problem with serious oxidation of area of the high temperature in the process, at the same time combinative other safeguard is reached solder reasonably standard, apparent land increased what nickel is in charge of to solder quality. Keyword: Industrial pure nickel; Protect a cover; Solder element of quality preface nickel has face heart cubic lattice, its characteristic is: Melting point is high, anti-corrosive, mechanical performance is high, there is good treatment performance below hot cold condition, have special content reason. Nickel still has good chemical stability, in normal temperature air, it is not corroded, admirable corrosion resistance is had in seawater and medium of salt of most soda acid can, it is especially in hydroxide and alkalescent solution, titanium of its excel of the function that fight corrode reachs titanium alloy, apply at the industry such as oil, chemical industry, shipbuilding widely consequently. Aborning, the material of canal of industrial pure nickel that we encountered thick 4mm of diametical 108mm, wall solders problem, through soldering to its function reachs the research of craft, enacted a special technology measure, use at actual production, obtained favorable result. One, the weldability of industrial pure nickel can analyse industrial pure nickel is a kind of rare metal, its solderability is better, but soldering in the process, aeriform impurity pollution is easy cause solder contact is fragile change. Below normal temperature, industrial pure nickel is stabler, lift as temperature, its function begins change, its absorb the ability of nitrogen, hydrogen, oxygen to rise apparently subsequently. The experiment proves, nickel is slight in air of 500 ℃ high temperature oxidation, when temperature achieves 750 ℃ , acuteness oxidation. As welding line the volume that contain oxygen rises, the tensile strength of welding line and hardness rise apparently, and welding line plasticity drops apparently, welding line becomes because of the pollution of oxygen fragile. The branch that nitrogen follows oxygen in the solubility of metal of high temperature liquid state is pressed increase and grow in quantity, the azotic effect to welding line intensity, hardness, plasticity is more more distinct than oxygen, the pollution that also says nitrogen is fragile change intention more more intense than oxygen, nitrogen basically is pair of concussion tenacity influences to the influence of welding line, the quantity that contain nitrogen increases, make the concussion tenacity of welding line is reduced significantly. Because prevent aeriform impurity to pollute what what cause hard,solder contact is fragile change, to its when undertaking industrial pure nickel solders craft raised special requirement, using common gas welding and manual arc welding is to cannot be satisfied solder of quality. Using solder of arc of tungsten pole argon is more reasonable solder method, but at the same time notable is, normally welding torch structure and craft are to be able to 't assure to solder of contact quality. Because this is planted,the aeriform covering layer that place of welding torch structure forms can be protected only solder bath does not get air pollution, right caky already and the welding line at high temperature condition and its heat affect an area not to have protective action. And the nickel that is in this kind of condition still has very strong absorption the ability of the nitrogen in air and oxygen, certainly will causes welding line to become fragile, and make plasticity drops badly. If welding line the reverse side does not take effective protection, also will produce similar result, the bath that is in high temperature to fuse and frit drop metal are polluted more easily by aeriform impurity. Accordingly, must adopt a series of safeguard, will raise what nickel is in charge of to solder quality. 2, rise solder the measure that quality should adopt 1. Assure to solder the premise of quality (1) inside the range that the impurity in mother capable person and welding wire must permit in technical condition; (2) use gas of tall purity argon to undertake soldering, solder contact should assure to show silvery white commonly; (3) workpiece is reached to must clear seriously to welding wire before solder; (4) choose welding wire correctly, solder standard and solder necessarily heat treatment; (5) the safeguard that strengthens bath and hot influence area. Think after undertaking an analysis to structure of welding wire, welding torch its won't cause pollution to welding line, reason is main from auxiliary protector, fixture, clear before solder wait for a respect to try to consider. 2. Abstain protection of gas full argon to overspread the protective limits to enlarge welding line, through self-restrained argon gas protection cover comes true. This protection cover is a basis contact form, welder art parameter will choose, the principle is: The area that is in 500 ℃ above can get effective protection, protective effect shows silvery white with welding line surface or buff is qualification. The construction that delays a cover and dimension are decided by the geometrical appearance of weldment, use commonly 0. The pure copperplate make it with thick 8mm grows 40mm ～ 100mm, 60mm of wide 30mm ～ overspreads body, thin weldment is some shorter, thick weldment is a few longer, a few wider. Argon gas enters distributinging canal by air inlet duct, distributinging canal is become with the stainless steel control of 1mm of φ 6mm × , in pipe upper part getting has two diameters 0.
8mm ～ 1.
The alveolus of 0mm, pitch is 8mm ～ 10mm, screen pack is used 0.
152mm × 0.
152(100 looks) copper wire is made, screen pack is not less than 8mm to the distance of weldment, aerate indoor not due blind angle, go out with achieving argon gas to squeeze all air, protective cover is in-house as far as possible make it round glide is crossed, prevent argon to enrage air current to form eddy current greatly too, soldering so gas of the argon in the process enters distributinging canal by air inlet duct inside, classics upper part is ejective get gentle rushs distributinging equably. After air current passes copper wire, get allocation again again, this improved the flow condition that argon enrages, make bath metal enrages advection layer to protect next caky figuration in argon directly. Welding torch and pull a cover to connect an organic whole in use process, operate in order to facilitate. 3. Other fixture is due and enough intensity and good thermal conductivity, clamping apparatus of water-cooling of the bolster plate that carry copper can satisfy above to ask. After clamping apparatus and protective cover are affirmatory, choice purity is 99.
The argon of 99% above is angry (examine the method of argon gas purity, it is to be in before gas of every bottles of argon is used, it is by normal standard on nickel board spot welding figures a drop, solder dot shows silvery white, the surface is qualification namely like lens face) , adjust different aeriform flow, observation protects the effect, determine appropriate protective gas flow finally. Film should oxidize nickel surface to clear clean before solder, after clearing, should solder as soon as possible, place time not to exceed 4h commonly. 3, solder craft assess (1) flaw detection of classics X ray does not have the stomatic, slag inclusion, blemish such as crackle, consult GB3323-1987 standard, can achieve Ⅱ class requirement. Welding line visual examination all is silvery white. (2) function checks contact machine, although compare mother capable person to be reduced somewhat, but accord with design requirement. 4, conclusion (1) weldability of industrial pure nickel can be better, solder with Tig and make fill metal with coessential welding wire, can obtain solder goodly contact. (2) the reliable protection when soldering and logical choice solder the standard is to ensure the premise of quality, the type that pulls a cover among them and protective effect are crucial technology. CNC Milling