What are the corrosion types of aluminum forging?

The forging of aluminum alloy will be corroded after long-term use, which is usually manifested as spot corrosion, galvanic corrosion, crevice corrosion, intergranular corrosion, filamentous corrosion, etc.

 

 

 

1. Point corrosion is a very local form of corrosion that produces needle, dot and porous forms on the metal. Point corrosion is a unique form of anodic reaction and autocatalytic process. The point corrosion limit is related to the dielectric alloy and the material which promotes the cathode reaction must also exist.

 

 

 

Second, galvanic corrosion is also a unique form of aluminum corrosion. Aluminum has a very low spontaneous potential. When it comes into contact with other metals, it is always at the anode, which speeds up its corrosion. The more serious the galvanic couple corrosion is, almost all aluminum alloy profiles can't avoid the galvanic couple corrosion.

 

 

 

Three, aluminum alloy profile itself or aluminum and other materials when in contact with crevice corrosion. Due to the different role of pneumatic battery, the corrosion inside the gap is accelerated, while there is no corrosion outside the gap. Sediment corrosion is a form of crack corrosion.

 

 

 

The cause of intercrystalline corrosion is related to improper heat treatment. Alloying elements or intermetallic compounds are precipitated along the grain boundary, and the corrosion cell is formed by the anode relative to the grain boundary, which accelerates the intercrystalline corrosion.

 

 

 

5. Filamentous corrosion is a kind of underwater corrosion under the helminthic membrane. This film can make the paint film and other layers, generally not lower than the anodic oxidation film. The filamentous corrosion is related to alloy composition, coating pretreatment of aluminum alloy profile and environmental factors such as humidity, temperature, chloride etc.

 

 

What is the factor that affects aluminium alloy deformation resistance?

 

 

 

With the decrease of temperature, the resistance of high temperature deformation increases rapidly, which is faster than that of carbon steel. It can be seen that the limit growth rate of high temperature strength is faster than that of carbon steel during drying. Aluminium alloys, especially those with a high degree of alloying, cannot be forged at low temperatures. Therefore, the forging temperature range of aluminum alloy is narrow, the operation should be rapid. The deformation resistance of aluminum alloy in the process of die forging determines the strength limit, processing conditions and the complexity of the forging.