Industrial fans are favored by consumers for the […]
Industrial fans are favored by consumers for their low cost, low power consumption, energy saving, beautiful appearance and other advantages. They are usually used in the form of ceiling fans. Because they are suspended in the air for a long time, they operate continuously every day, plus some work. The environment is relatively special, which has high requirements on the material and welding process of industrial fans. Most of the materials of industrial fans are aluminum alloy, which requires the use of high-efficiency welding methods with high welding speed. Today, I will explain to you. Here is a common welding process for industrial fans.
One, friction stir welding
1. The working principle of friction stir welding is to insert a special type of stirring head into the part to be welded. Through the high-speed rotation of the stirring head, the friction stirs between the workpiece and the friction generates heat to make the metal in the part in a thermoplastic state. The plastic flows from the front end to the back under pressure, so that the weldments are welded together. Since there is no melting of metal in the friction stir welding process, it is a solid state connection process, so there are no defects of fusion welding during welding.
2. Compared with the traditional fusion welding method, friction stir welding has no spatter, smoke and dust, no need to add welding wire and shielding gas, and the joint performance is good. Because it is a solid phase welding process, the heating temperature is low, and the microstructure changes in the welding heat-affected zone are small. For example, the metastable phase remains basically unchanged. This is very beneficial for industrial fan blades that require high-altitude balance.
3. The residual stress and deformation after welding are very small, and there is basically no deformation after welding of thin aluminum alloy. Compared with ordinary friction welding, it can weld straight welds and fillet welds without being restricted by shaft parts. The traditional welding process of welding aluminum alloy requires removing the oxide film on the surface and processing it within 48 hours, while the friction stir welding process only needs to remove the oil stains before welding and does not have high requirements for assembly.
Two, laser welding
1. Laser welding technology is a new technology developed in the past ten years. Compared with traditional welding technology, it has the characteristics of strong function, high reliability, no vacuum conditions and high efficiency.
2. It has the advantages of large power density, low total heat input, large penetration of the same heat input, small heat affected zone, small welding deformation, high speed, easy industrial automation, etc., especially for heat-treated aluminum alloys. It has greater application advantages .
3. It can increase the processing speed and greatly reduce the heat input, thereby increasing the production efficiency and improving the welding quality. This can greatly improve production efficiency for manufacturers who produce large quantities of industrial fan blades and racks. Compared with contact welding, laser welding does not use electrodes, so it reduces man-hours and costs; it does not require the vacuum atmosphere of electron beam welding, and the shielding gas and pressure can be selected. The shape of the welded workpiece is not affected by electromagnetics and does not produce X-rays. .
Three, electron beam welding
1. Electron beam welding refers to a welding method in which the welded metal is fused by using the heat generated by the convergent high-speed electron current to bombard the joints of the workpiece in a vacuum environment.
2. The outstanding characteristics of the electron beam bombarding the workpiece as the welding heat source are high power density, strong penetrating ability, fast, controllable, and good protection effect. For aluminum alloy electron beam welding, due to the high energy density, the heat-affected zone can be greatly reduced, the strength of the welded joint can be improved, and the occurrence of defects such as hot cracks can be avoided.
3. Due to the high energy density and strong penetrating ability, it can weld thick aluminum alloy plates that are difficult to weld. Compared with the traditional arc welding aluminum alloy, the energy density of electron beam welding is 3-4 orders of magnitude higher, which is comparable to another high energy density welding process—laser welding. Therefore, the heat-affected zone of the welded joint is very small, and the strength of the joint is much higher than that of the traditional welding method.
4. The electron beam has good penetration performance, which can weld large thickness aluminum alloys, and the mechanical properties of the joints after welding are good. The crack resistance of aluminum alloy weld metal increases with the increase of welding energy density and the decrease of heat input.