Of aluminium and aluminium alloy data

Aluminium and density of aluminium alloy data are low, intensity is high, pyroelectricity conductance is tall, anti-corrosive ability is strong, have outstanding physical character and mechanical use, solder because of what this applies extensively at industrial product on the structure. Long-term since, because solder,the method is reached solder the choice of technical parameter is inappropriate, after forming aluminium alloy spare parts to solder because of stress too meeting market show effect is out of shape badly, or as a result of welding line stoma, slag inclusion, not solder is appeared wait for blemish, cause crackle of welding line metal or material is loose, affected product quality and use badly.

Feature of data of 1 aluminium alloy

Aluminium is the light metal of silvery white, have outstanding plasticity, taller conductivity and thermal conductivity, still have together fight oxidize and fight corroded ability. Aluminous very brief oxidation breaks out 3 oxidation 2 aluminium are filmy, field trash of brief in welding line fit, damage next of the metal successional with uniformity, drop its machinery function and anti-corrosive function. See the chemical composition of capable person of aluminium alloy mother and welding wire and mechanical use more.

Of data of 2 aluminium alloy solder difficulty

(1) is very brief oxidation. In air, the aluminous brief chemical combination that be the same as oxygen, generate close 3 oxidation 2 aluminium are filmy (ply makes an appointment with 0.1-0.2 μ M) , melting point is high () of about 2050 ℃ , far the melting point of exceed aluminium and aluminium alloy (about 600 ℃ order about) . The density 3.95-4.10g/cm3 of alumina, it is 1.4 times aluminous about, the exterior easy adsorbed water of alumina film is divided, when soldering, the fusion of metal of a copy kept as a record of its block up, very brief make the defect such as stomatic, slag inclusion, incomplete fusion, cause welding line function to drop.

(2) easy fit is stomatic. The chief reason of stoma of the fit when aluminium and aluminium alloy solder is hydrogen, because liquid state aluminium can dissolve very much hydrogen, and solid state aluminium dissolves scarcely hydrogen, because this is become bath temperature is fast when refrigeration and agglomeration, hydrogen has not enough time transgression, brief assemble in welding line make air hole. Hydric aperture is hard to avoid completely at that time, hydrogenous antecedents is very much, have the hydrogen in arc welding atmosphere, the moisture in air of adsorption of surface of aluminium board, welding wire. Carry out a proof, gas of even if argon requests by GB/T4842 standard, purity arrives at 99.99% above, but when moisture content arrives at 20ppm, also can present a lot of close stoma, high above in the sky enrages relative humidity exceed 80% when, welding line can present air hole apparently.

(3) welding line is out of shape and make crackle trend big. Aluminous line swells coefficient and crystallization shorten rate compare steel about big double, easy show effect is bigger solder metabolic internal stress, older to tigidity structure will accelerate the show effect of hot crack.

(The coefficient of thermal conductivity of 4) aluminium is big (aluminium 0.538 calories / Cm.s. ℃ ) . It is 4 times of steel about, accordingly, solder when aluminium and aluminium alloy, the steel that compare solder should use up more quantity of heat.

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