The hottest laser assisted friction stir welding

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Laser assisted friction stir welding

laser assisted friction stir welding (lafsw) is a new and improved friction stir welding. Friction stir welding is a process developed in recent ten years

in friction stir welding, the welding heat energy comes from the friction heat between the tool and the workpiece. Because this process requires relatively large force, the equipment used in friction stir welding is bulky and expensive. Laser assisted friction stir welding uses laser energy to heat the workpiece, and the main function of the stirring head is to stir and connect the workpiece. For this reason, laser assisted friction stir welding is a relatively simple and cheap method

this article discusses the use of lafsw to connect az91dmg alloy and the advantages and disadvantages of using this process

1 laser assisted friction stir welding

in order to overcome the shortcomings of friction stir welding, such as (1) the fixture for clamping the welding workpiece is large, which requires a lot of force to move the welding tool forward, and the wear rate of the welding tool is relatively high; (2) The correct position cannot be guaranteed by heating with induction coil. The welding mixing head and fixture device are affected by the heating induction coil. The induction coil is used as the medium for heating and is only applicable to conductor materials, and cannot be used for other non-metallic and non-conductor materials. Laser assisted friction stir welding has been developed. This method is transformed from general milling machine and nd:yag laser. Laser energy preheat the workpiece in a limited range in front of the rotating mixing head. In this way, the volume and plasticity of the workpiece in front of the rotating mixing head increase (Illustration 1). Then, the workpiece is connected in the same way as that of ordinary FSW workers in the field of industrial investment casting. The high temperature in front of the rotating tool softens the workpiece, and the connection can be ensured without strong fixture clamping. Moving the welding tool forward requires only a small force, so wear is reduced. For laser energy, this process also has the advantage of high welding ability, which will not cause too much wear during welding. The commercial laser has a laser diameter control device that is accurately controlled by specially adjusted TPU material. Therefore, it is relatively easy to control the heating area of the workpiece and the number of laser sources reaching the workpiece, and maintain the heating of other parts of the system

Figure 1 principle of laser assisted friction stir welding

2 establishment of test

700-w with 1064 nm wavelength, multi-mode nd:yag laser system and general 3-HP rotary frame end milling machine are used in welding test

four test pieces are clamped on the platform of the end milling machine Ф 23 mm pin, one made of high speed steel Ф 2 but at present, cylindrical tools with 0 mm straight handle are embedded with a length of 4 mm, Ф 9 mm mixing head. Pass 800 μ M-core 5m long optical fiber directly transmits the laser beam to the welding workbench. Formation of beam defocusing in front of mixing head Ф 1 cm light spot (see picture). Using thermocouples to weld the surface of similar test pieces to a predetermined working temperature, a 200W power laser can heat the test pieces to about 320 ℃, and the rotation speed of the shaft is 1700rpm

3 conclusion and discussion

the two 4 mm thick figures above are a new type of lightweight, high-strength, flame retardant and highly elastic metamaterial cross-section mgaz91 alloy plate, which is connected according to the parameters described above, as shown in Figure 2

because this research is only a preliminary work, it is also necessary to find the best combination of laser and FSW parameters in the mechanical properties of the workpiece and the production capacity of the combined process. Lasers can be used to heat non martensitic materials, such as plastic materials and ceramics. The type of lafsw welding connecting these materials will be further studied

4 Conclusion

the welding process of laser assisted friction stir welding has been proved. The use of laser to preheat the workpiece marks the reduction of the need to provide greater force in welding tools and workpieces. This improved method simplifies the use, so it is possible to use economic welding methods. In addition, higher welding speed has obtained better benefits in the improvement

(compiled according to laser assist friction stri welding in Welding Journal, original author HN, eenberg, kover, Nitz) (end)

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