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/Analysis of several common defects of extruded aluminium alloy profiles 2

Analysis of several common defects of extruded aluminium alloy profiles 2

2021-03-29

Formation of "adsorbed particles"

Reason 1) aluminum rod quality due to the high temperature casting, the influence of casting speed, cooling intensity big, cause the alloy phase AIFeSi B can not timely AIFeSi into a ball, the phase AIFeSi B present acicular structure in the alloy, high hardness, plasticity, low tensile strength, will not only induce extrusion cracking during hot extrusion, and produce granular burr, the burr is not easy to clean, feel strong, grain is often accompanied by a tadpole shape near the tail, on the metallographic microscope, beige, the ingredients are rich in iron.Impurities in the aluminum rod, aluminum rod in the casting process, refining is not sufficient, soil, refining agent, covering agent and powder coating and oxide film inclusion mixed into the rod, these materials in the extrusion process, the plastic and tensile strength of the metal significantly reduced, easy to produce granular burr.Stick the tissue defect of common have loose grain, coarse grains, segregation, brightness, etc., all these cast bar defects have one thing in common, which is with welded bad casting rod matrix, the matrix of flow discontinuity caused by in the process of extrusion, the slag is easily separated from the substrate, through working with mold, the adhesion at the entrance to the end, forming sticky aluminum, and pull by continual flow of metal, easy to produce granular burr.In the extrusion production, the mold works under the condition of high temperature and high pressure. Under the influence of pressure and temperature, the mold produces elastic deformation.


The working belt of the die is parallel to the direction of extrusion at the beginning. After being subjected to pressure, the working belt changes into a horn shape. Only the cutting edge of the working belt contacts the sticky aluminum formed by the profile, which is similar to the knife chip tumor of turning tool. In the forming process of aluminum bonding, the particles are constantly taken out by the profile and adhered to the surface of the profile, resulting in "adsorbed particles".With the continuous increase of the adhesive aluminum, the die will produce instantaneous rebound, and the bite mark defect will be formed.If the sticky aluminum accumulation is more, it can not be pulled out by the profile, and the sticky aluminum does not fall off when the mold recoils instantly, it will form the surface roughness, bright strip, profile tearing, die blocking and other problems of the profile.


Related Products: Aluminum Profile,Aluminium Window Profile,Aluminium Extrusion Profile


 
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