In the extrusion production of aluminum profiles, profiles of different degrees of surface there are some small particles adsorbed on the aluminium alloy profile surface, this defect, only a slight feel, not carefully observed or hand touch is difficult to find. But it seriously affects the surface beauty of oxidized, electrophoresis painted and sprayed profiles, reduces the production efficiency and yield, and is the fatal defect of high-grade decorative profiles.Therefore, to analyze its formation mechanism, at the same time in the extrusion production practice constantly observe and analyze, summarize its causes, take timely measures, is to reduce or eliminate the emergence of this defect effective means.

1. There are four kinds of granular burrs on the surface of extruded profiles: 1) air dust adsorption, dust, aluminum chips, oil and water produced by coal-burning aluminum rod heating furnace condense into particles attached to the surface of hot profiles.2) Impurities in aluminum rods, such as metal inclusions and non-metal inclusions left over from inadequate refining.3) Dust adhesion in aging furnace.4) Defects in aluminum rods and B-phase AiFeSi in components precipitate at high temperature, which reduces metal plasticity and tensile strength and produces granular burr.