Text 1: Laser Beam Welding of AA5052, AA5083, and AA6061 Aluminum Alloys
In the article of A.El-Batahgy and M.Kutsuna named Laser Beam Welding of AA5052, aa5083, AND aa6061 Aluminum Alloys, it is aimed to develop the laser welding method that has been developing in recent years. Aluminum alloys are among the most preferred construction materials in recent years, especially in terms of lightness, ease of processing and economy, and their mechanical properties are also quite good. Laser welding has not yielded efficient results in aluminum alloys so far, and in this study, the effect of filler particle as well as optimal welding speed and laser power for aluminum alloys were investigated.
The experiment started with a pre-cleaning step with a metal brush and nitric acid solution. This is a very important step because it is aimed to minimize the reflection of the laser beam. This is only possible by minimizing the surface roughness. The experiment was carried out in the laser power range of 3 and 5 kW, welding speeds of 4 m/s and 6 m/s, and shielding argon gas velocities of 15 l/s and 25 l/s. The laser spot diameter was set at 700 micrometers and the focal length was 200 mm.
During the experiment, it was seen that the surface porosity, cleanliness and speed of the argon gas are very effective. The use of high-power intensity focused CO2 laser beam with optimized parameters and careful material preparation prior to welding can produce welds with high quality for both AA5000 and AA6000 series alloys. Welding speed of 6m/min and laser power of 4kW have resulted in full penetration of 2mm thickness welded joint while 5 m/min and 5kW have resulted in full penetration of 3mm thickness welded joint. All the investigated alloys showed tendencies for porosity and solidification cracking particularly, at high welding speed (≥ 4m/min).
Text 2: Laser welding process specification base on welding theories
Fundamentals of laser welding are examined in Tunde Kovacs’ article titled Laser welding process specification base on welding theories. The laser technology is a high energy beam fusion welding process with low heat effect. The laser beam has high energy therefore it’s useful for fusion welding technology.
The laser energy penetration depth is very small, about 1mm/ kW. Which means to use laser for welding application we need a high-power source. The melted metal forms depend also on the welding speed, the laser power level and the focus position too. These laser parameters can determine by the empirical experiments results.
The welding process specification includes all information needed to prepare a quality joint based on the welded metal chemical composition and geometry of the used welding process parameters. The laser heat effect depends on the laser energy density and the interaction time The knowledge of the effects of gases, focal position and needed power density are important to do a laser welding specification.
The laser source development is also very rapid nowadays, and useful widely. The power density is also a lot higher than few years ago. We know different laser types (CO2 laser, YAG laser, Disc laser, Fiber laser) with different properties. The process can be modelled by using a relatively simple analytical method to obtain initial estimates for parameter selection in procedure development. To achieve the highest level of detail for practical use, models may be calibrated to known data points to produce a practical processing diagram
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