Causes and elimination of blistering and skinning on the surface of extruded aluminum profiles

Causes of bubbles and peeling: 　　1. Extrusion cylinder and squeeze pad are worn out, the size of the squeeze cylinder and squeeze pad are not properly matched, and the difference in diameter of the gasket used exceeds the allowable value; 　　2. Squeeze cylinder and extrusion The pad is too dirty, sticky with oil, moisture, graphite, etc.; 　　　　3. Lubricant contains water; 　　　4. The surface of the ingot has too many shovel grooves, too deep, or the surface of the ingot has pores, sand holes, loose tissue, oil, etc.; 5. When replacing the alloy, the inside of the barrel was not cleaned; 　　　 6. The temperature of the extrusion barrel and the extrusion casting temperature were too high; 　　　 7. The temperature and size of the ingot exceeded the allowable negative deviation; 　　　　 8. The ingot was too long, the filling was too fast, and the casting The uneven temperature of the ingot caused non-drum filling, so the exhaust in the cylinder was not complete, or the operation was improper, and the exhaust process was not performed; 　　　 9. The die hole design is unreasonable, or the residual material is improperly cut, in the diversion hole and the diversion hole The residual material is partly taken out, and the gas in the gap enters the surface during squeezing. Solution: 　　 1. Reasonably design the matching size of the extrusion cylinder and the extrusion gasket, and check the tool size frequently to ensure that it meets the requirements. The squeeze cylinder should be repaired in time if there is a big belly, and the extrusion cushion should not be out of tolerance; 　　　 2. Tools, casting Keep the surface of the ingot clean, smooth and dry; 　　3. When changing the alloy, thoroughly clean the tube; 　　4. Check the equipment and instruments frequently to prevent excessive temperature and speed; 　　5. Strictly implement the process regulations and various systems; 　　6. Reasonable Design and manufacture tools and molds, the diversion hole and the diversion hole are designed to have an internal slope of 1°-3°; 　　7. Strict operation, correct cutting of residual materials and complete exhaust. ————The article comes from the Internet. If there is any infringement, please contact to delete it.