ã€China Aluminum Industry Network】 Metallic beans ---Aluminum alloy profiles are accompanied by spherical gray-black hard particle metal with loose structure. In the aluminum alloy surface energy can be wiped off and wiped off two kinds. Photoelectric Fiber Optic Sensor Lenses Photoelectric Fiber Optic Sensor Lenses,Laser Beam Focusing Lens,Laser Beam Expander Lens,Clear Plastic Optical Lenses Dongguan Lianlong Photoelectric Technology Co., Ltd , https://www.lianlonggd.com
Glitch (triangular opening) --- The front-end wide-recessed pit formed by the enlarged black hard particle metal after rubbing the surface of the aluminum alloy profile and the frictional uplifting and falling of the flowing profile.
Causes of aluminum defects:
(I): The alloy composition of aluminum rods, the amount of silicon Si and the amount of iron Fe are high, and the magnesium Mg Si and Si ratio is not proper (silicon content exceeds the standard value). Excess silicon and iron will be more active than aluminum metal. In the Al-Mg-Si crystal phase of Al-Mg-Si, the magnesium atoms were combined to form Mg2Si Mg2Si phase and AlFeSiAlFeSi phase, which made the crystal grains coarse and needle-like. The performance was lively, the hardness increased, and the plasticity was poor. This majority of metal beans can rub (alkali wash) off (b): aluminum extrusion mold work with hardness is not enough, the dead angle is too large, used too long, work with too long.
(C): The aluminum extrusion speed and the extrusion temperature are too high, and the aluminum rod is too long to press into the surface aluminum.
(d): mats and mats, cushions and cylinders with the poor tolerance, metal beans are often deep embedded aluminum surface and rub (alkali wash) can not afford.
(five): foreign debris and air dust adsorption.
(6) When the production of hot rods is premature, the temperature of the surface layer of the aluminum rods decreases, and the crystal grains are coarsened. Special attention should be paid to the production of hard alloys.
Elimination method:
The key to the elimination of metal beans in aluminum alloy profiles lies in the quality of the aluminum rods. Excessive iron content in the silicon-containing alloys is a major problem that causes the surface to have particulate metals. During the aluminum production process, the pad and pad, and the mat between the pad and the cylinder are very poor, so that the relative stable surface layer of aluminum in the extrusion cylinder is destroyed. These same temperatures as the cylinder temperature (about 400 degrees) are obviously lower than the extrusion temperature. The stick-temperature adhesion of surface aluminum slowly peels off from the barrel wall with the friction between the metal, forming fine, low-temperature, slightly harder ALFeSi metal particles, which are pressed into the profile surface through the die hole, forming a hand-rubbed-off. Metal beans.
Another reason I encountered was that: 630 tons of aluminum in Changfa Aluminum Co., Ltd. produced 6061 heavy-dull burrs on the surface of the coils, the rods were ineffective, and production of 6063 was not. After that, the temperature of the phase failure of the cylinder was only 365 degrees, and the temperature was 390 degrees after repair. The profiled burr disappeared. The reason is that the speed of the 6061 vehicle is slow, and the temperature of the rod and the wall of the bar (520°C) during the heat-transfer and cooling process of the Mg2Si-Mg2Si phase and AlFeSi-Al phase is concentrated on the surface of the aluminum rod and is reflected in the surface of the profile through the dead zone. come out.
After the shearing pressure, the mold surface is uneven and the metal beans appear on the surface of the profile.
If the quality of the rod is poor, mating between the mat and the mat, the mat and the cylinder is seriously different, and the metal beans will become coarse. When the mold holes are extruded, they will be stacked at the working belt outlet to adhere or scratch the surface of the aluminum alloy profiles. , forming a burr on the surface of the profile (triangle mouth).