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What are the welding characteristics and performance of aluminum profiles

The main component of aluminum profiles is aluminum, and there is a small amount of alloy components. Aluminum has excellent welding performance, so aluminum profiles are also easy to weld and process. However, the welding of aluminum has its own characteristics compared with other metals, so the welding process of aluminum profiles should follow the welding characteristics of aluminum to avoid poor welding.
1. Aluminum profiles are easily oxidized to form aluminum oxide in the natural environment, and aluminum oxide isolates the air and also plays a role in protecting the aluminum matrix. However, aluminum also undergoes oxidation reaction during welding. The resulting alumina has a very high melting point, is very stable, and is not easy to remove, which hinders the welding process, and the oxide film has a high density and is not easy to surface. It is easy to form slag inclusions and poor welding. and other defects. Therefore, it is necessary to remove the oxide film before welding the aluminum profile, and to prevent the oxidation reaction during the welding process.
2. Aluminum alloy can dissolve a large amount of hydrogen in liquid state, but this situation does not exist in solid aluminum alloy. The dissolved hydrogen in the molten aluminum alloy during welding has no time to precipitate, and hydrogen holes are easily formed during rapid solidification. Therefore, it is necessary to control the moisture on the surface of welding materials and aluminum profiles, and water is the source of dissolved hydrogen.

3. The thermal conductivity and specific heat capacity of aluminum are more than twice that of carbon steel and low alloy steel. Aluminum alloy profiles will waste a lot of heat during welding. In order to obtain higher quality welded joints, aluminum profiles should be welded with higher power and more concentrated power sources. If necessary, use preheating process measures.
4. Aluminum has strong reflective ability to light and heat, and there is no obvious change in color and luster when solid and liquid are in transition, making it difficult to judge during welding operations. High temperature aluminum has low strength, it is difficult to support the molten pool, and it is easy to weld through.

5. The coefficient of linear expansion of aluminum alloy is also twice that of carbon steel and low alloy steel. When the aluminum welding pool solidifies, shrinkage cavities, hot cracks and high internal stress are prone to occur. Therefore, when welding aluminum profiles, aluminum-silicon alloy welding wires are used to weld aluminum alloys other than aluminum-magnesium alloys.

6. The aluminum profile contains alloying elements, and the alloying elements are easy to evaporate and burn, which reduces the performance of the weld.

7. Aluminum profiles are generally heat-treated reinforced aluminum alloys. During the welding process, the welding heat will affect the strength of the aluminum profiles in the hot zone.

8. Compared with other metals, aluminum has no phase change during the heating process, and the coarse grains caused by welding cannot be refined through the phase change.

Aluminium Construction Profiles


Post time: Jun-20-2022