ã€China Aluminum Industry Network】 In the extrusion production of aluminum profiles, there are some small particles on the surface of the profile that are adsorbed on the surface of the profiles in different degrees, and the hand feels a touch, which affects the surface appearance of oxidation, electrophoretic painting and sprayed profiles and reduces Productivity and yield. Therefore, the mechanism of its formation is analyzed in order to take measures to reduce or eliminate the appearance of defects in such profile tables. In the extrusion production of aluminum profiles, the common defects are relatively intuitive, such as bending, twisting, deformation, slag inclusions and so on. The "adsorbent particle" defects are not easily observed or hard to find. The harm is: in the electrophoresis, spray profile production process, it is difficult to remove, affect the appearance of the appearance of the profile, resulting in waste. Therefore, we must constantly observe and analyze in the extrusion production practice, summarize its causes, and take timely measures to reduce or eliminate the occurrence of such defects. 1 The performance of "adsorbent particles" and its impact on product quality More and more methods of aluminum surface treatment, in addition to the general oxidation profile, electrophoresis profiles, spray profiles, fluorocarbon spray profiles, wood grain paint profiles, etc. have appeared one after another. There are many tricks. The defects of “adsorbent particles†have little effect on general oxidized materials, but they have a great influence on other forms of treatment, mainly impeding the appearance of these profiles. In extrusion production, the extruded profile “adsorbent particles†can be found after careful observation or by hand sliding on the surface of the profile. In the sawing and packaging process, most of the small particles can be removed by blowing or wiping. However, some of them are still adsorbed on the surface of the profile due to static electricity. After aging treatment, these particles adhere more closely to the profile surface. In the pretreatment process of the profile surface, some of the pits can be removed due to the influence of the concentration of the bath solution, but small pits are formed on the surface of the profile, and some of them are not removed, so that the protrusions are formed. This problem often occurs in the production of electrophoretic and spray profiles. 2 Reasons for formation of “adsorbent particles†2.1 Effect of the mold In the extrusion production, the mold is operated under high temperature and high pressure, and the mold is elastically deformed under the influence of pressure and temperature. The working belt of the mold starts from parallel to the extrusion direction, and after the pressure is applied, the working belt is deformed into a trumpet shape. Only the edge portion of the working belt contacts the aluminum stick formed by the profile and is similar to the cutting edge of the turning tool. In the formation of sticky aluminum, particles are constantly being carried out by the profile and adhere to the surface of the profile, resulting in "adsorbent particles". With the continuous increase of sticky aluminum, the mold will instantly rebound and bite marks will be formed. If the sticky aluminum deposits are too large to be pulled out of the profile, the sticky aluminum does not fall off when the mold instantly rebounds, and the problem arises that the surface of the profile is rough, bright, tearing of the profile, mold blockage, etc., and the sticking aluminum phenomenon of the mold is shown in FIG. 1. The extrusion die we use today is basically a planar die. In the case where the cast bar is not stripped, the surface and internal impurities of the cast bar deposit in the dead zone of the metal flow in the die, with the advancement of the extrusion die and the number of extrusions With the increase, the impurities in the dead zone are constantly changing. Some of them are carried out by normal flowing metal and accumulate in the deformed space of the working belt. Some were pulled off the profile to form "adsorbent particles." Therefore, the mold is the key factor causing "adsorbed particles". 2.2 Influence of extrusion process The correct choice of extrusion process parameters is also an important factor affecting "adsorption particles". After on-site observation, the extrusion temperature and extrusion speed are too high, the more “adsorbent particles†are, because the temperature is high and the speed is fast. The flow speed of the profile increases, the degree of deformation of the mold increases, the metal flow speeds up, and the metal deforms. Relatively weak resistance, more likely to form a sticky aluminum phenomenon; for a large extrusion coefficient, the metal's deformation resistance is relatively increased, the dead zone is relatively increased, and the conditions for the formation of sticky aluminum are increased, and the probability of formation of "adsorbent particles" increases; The difference between the casting rod heating temperature and the mold temperature is too large, it is also easy to cause sticky aluminum problems, or even blocking the mold; the mold surface roughness, the hardness of the working belt surface, etc., is also caused by sticky aluminum, the formation of "adsorbing particles" of the reasons one.