People up production of aluminum alloy laser welding machine how to ensure the quality of welding process
Aluminum alloy laser welding industry is now more difficult to welding material, and the material of its widespread use in automobiles, machinery manufacturing and chemical industry, especially the construction industry, use the market demand for cars is also extremely, in each big factory increased investment in r&d and manufacture of aluminum alloy processing, the welding of aluminum alloy has become a have to toil for a title, a good background to want to get to know each other is the welding of aluminum alloy welding processing difficulties, it must first understand the welding characteristics of aluminum alloy, also the laser welding difficult talent from the source. A, how do the welding characteristics of aluminum alloy samples, what are the defects: 1, now, established important acceptance of TIG welding, MIG welding methods essentials to welding of aluminum alloy, accept money, to bring the welding. 2, heat output from weld punished severely and shallow depth of molten aluminum alloy thermal conductivity is fast, metallurgy doesn't dissolve a small amount of hydrogen at low temperature when excessive inoculation hydrogen attack air hole ( Precipitate dissolve into the hydrogen in the molten pool form pores, called metallurgy porosity. 3, the moisture in not completely molten oxide film due to heating component separation of hydrogen pores, called oxidation membrane pores) 。 4, due to the metallurgical rate fast weld metal coarse grains, welding discuss hardening can make strength reached 40%. 5, low melting point and thermal conductivity is fast, molten metal active looking bad and make the weld shape. 6, large heating area, processing the material easy to deformation and affect the processing dimensional accuracy. Established 7, aluminum alloy methods to guarantee the welding quality and welding speed is difficult to good batch consumption demand. Second, the laser welding of aluminum alloy characteristics: 1, whatever the welding point, the aluminum alloy welding prepare things before will not less, had a great influence on welding quality of aluminium alloy. 2, welding of aluminum alloy parts appearance before try anhydrous alcohol or acetone to clean, to eliminate appearance are adsorption impurities such as water or oil. 3, to prevent the workpiece by oxidation in the atmosphere, the workpiece held by machine or chemical necessary disposal dispose and drying, as soon as possible to complete the welding. 4, in order to slow down when aluminum alloy welding molten pool activity, can be padded on the underside of the aluminium alloy workpiece welding copper to improve weld forming. 5, welding, acceptance of Ar gas cover, deter atmosphere, can mean reducing hole attack. As laser processing using the universal level selection, take on the laser welding of aluminum alloy, small heat output and heat source rendezvous, especially after the advent of optical fiber laser energy density of laser welding of aluminium alloy confluence, laser wavelength shorter, high reflecting improved lost. After laser wire filling, dual light such as the laser welding process, can be significantly improved forming consequences of aluminum alloy welding, welding quality and lost. Mining industry to grow bald, can be roughly stable welding quality. With deepening of laser processing, effect is more and more use with rapid expansion of bald lost. Now developed by Scansonic and HighYAG excitation bald, can roughly within a certain range around the floating up and down and not shift flare intrusive, joint also does not affect the light silk, very conducive to mass consumer use, can improve the material for processing and gave birth to attack the large size of faults and provoked weld defects. Acceptance of welding process parameters, which can be about guaranteeing the welding quality. Figure 8 of 6061 aluminum alloy wire filling laser welding parameters of the optimization of the laser power and welding speed connection diagram. Can see from the picture, the optimization of laser power and welding speed vertical chamber rise by linear parameter curve, the slope basic link. Each given laser power value, on the optimization parameter curve has a optimized welding rate and the matching, in a certain range and the welding speed innovation can still lose a good weld forming quality, the region belongs to the weld region. In a power value, when welding speed is too large, heat output decreases, aluminum alloy plate means less penetration, the weld is above the plateau range up rate is too high, belong to not fusion zone; When welding speed is too small, too much heat output, molten pool under serious collapse, belongs to the molten pool area collapsed at this time. To lose the stability of the weld forming, need welding process parameters of conjunction of the room. Beginning, aluminum alloy laser welding of high reflective signs, serious influence of laser energy absorbing material, and the shorter the wavelength, the light absorbing material is better, optical fiber laser is better than absorbing CO2 laser for aluminum alloy, optical fiber laser beams will be better than CO2 laser, the more energy density rendezvous, once the material start to absorb light energy, the liquid metal light reflectivity is significantly decreased. Accept double speckle laser welding, can significantly improve the porosity, about important is held due to accept double beam welding, two beams of light constitutes an absolute bigger keyhole, improve the stability of keyhole, is advantageous to the gas escape; Compared with serial double beam, acceptance of parallel double beam welding, high speed of liquid metal agglutination, extension of bubbles escape, is conducive to mean reducing hole inclination; Parallel dual beam laser welding can improve the stability of wire feeding, good for stable welding quality. Accept wire filling welding, laser can lose about a better shape. Laser wire filling welding can roughly compatible with high energy density of laser welding and wire filling welding of gaoqiao, do have a certain gap of weld, can about guaranteeing the excellent forming consequences. And by selecting the difference in addition to fill material, can be held to the parent metal and chemical metallurgy, play a alloy elements supplemented and strengthening effect. Accept gauge compound welding, after laser and electric arc compound, can be useful about eliminate the effect of plasma in the composition of laser welding, can lose about regards the weld, and make thick plate without open groove or just open a small groove can constitute a good weld.