1. The welding rod cannot be heated with a welding gun and then dipped in welding powder because the melting point of the welding rod is too low.
2. The one-time successful welding effect is better. Because the point of Kunshan aluminum rod fusion rotary cutting tool is too low, it is easy to deform when reheated for the second time.
3. A wet towel must be placed in the inner container to protect it in place, because the welding space is very small, so be sure to pay attention to the protection of the refrigerator.
4. The flame of the welding gun cannot be too long and must be heated with a low fire, otherwise the dispersant aluminum tube will easily melt.
5. After welding is completed, wait for two or three minutes for the nylon wire special slurry to cool down before the cement storage tank can be contacted, otherwise the solder joints are prone to leakage.
6. The welding rod must be evenly coated with flux to ensure the quality of the solder joints.
7. The welding time should not be too long. Because the melting point is too low and the time is too long, it will easily cause the wall of the aluminum pipe to melt or become thinner, and it will easily leak when pressed.
8. The welding rod cannot be heated with a welding gun and then dipped in welding powder because the melting point of the welding rod is too low.
1. Principle of aluminum welding
The principle of aluminum welding is to use arc or other heat sources to melt aluminum or aluminum alloy materials, and under the action of a certain pressure and protective gas, make them penetrate and fuse with the base metal or filler metal to achieve connection. However, there are also some difficulties and problems in aluminum welding, mainly as follows:
There is a dense oxide film on the surface of aluminum and aluminum alloys. The melting point of this oxide film is several hundred degrees higher than that of the base material. It is also highly inert and difficult to be destroyed. If the oxide film is not removed, the stability of the arc and the formation of the molten pool will be affected, resulting in weld defects.
Aluminum and aluminum alloys have high thermal conductivities, about four times that of steel, which means they require greater heat input to reach melting temperatures and the heat is lost quickly, resulting in larger heat-affected zones and greater deformation.
The volume shrinkage of aluminum and aluminum alloys during solid-liquid phase transition is very small, about one-tenth that of steel. This will increase the surface tension of the molten pool, making it difficult to flow and diffuse, and prone to defects such as pores and slag inclusions.
Aluminum and aluminum alloys will undergo precipitation hardening during the solidification process, that is, some alloying elements precipitate from the solid solution to form fine dispersed phases, which increases the strength and hardness of the material. However, if precipitation hardening is uneven or excessive, it will reduce the plasticity and toughness of the material and affect the mechanical properties of the weld.
Therefore, aluminum welding requires some special methods and techniques, such as removing oxide films, using protective gas, selecting appropriate filler metal, controlling heat input and cooling rate, etc.
