◆Aluminum ingot and extrusion crackOne is that the hot cracks generally crack along the crystal, the cracks are black, and have been oxidized, and the cracks are jagged and irregular in shape;
The other is that the cold cracks cracked from the inside of the crystal, the cracks were not oxidized, and they were shiny in silver fold lines.Preventive measures: Strengthen the inspection of aluminum alloy materials, the impurity content exceeds the standard and the original organization is unqualified and is not put into production; strictly control the temperature control instrument during production, the temperature control accuracy must reach ±1.5 ℃; for different brands of aluminum alloy blanks, formulate corresponding Reasonable heating temperature to ensure uniform heating; formulate extrusion speed and extrusion deformation amount suitable for different brands of aluminum alloy to make the thermoplastic deformation as uniform as possible; improve the mold structure design and make the corners of the extrusion section as large as possible; test It shows that the uniform annealing of aluminum ingots in advance (540℃～560℃, heat preservation for 4-6h) can reduce the extrusion force by 15%-25%, increase the extrusion speed by 10%-15%, and significantly increase the thermoplasticity. The above measures can effectively prevent and avoid the occurrence of extrusion cracks.
◆Bubble peelingPrecaution. Improve the quality of aluminum ingots, select high-quality aluminum ingots and strict aluminum warehouses and check before production; replace severely worn extrusion cylinders and extrusion pads in a timely manner, and keep them clean and smooth; control the atmosphere of heat treatment to prevent the reduction of water vapor into people For the lubrication of the extrusion gasket and die, adjust the extruder to make the action uniform and coordinate, formulate a reasonable extrusion speed and extrusion deformation to ensure the smooth exhaust; the preheating temperature of the extrusion barrel should be lower than the heating temperature of the aluminum billet 25℃--35℃; prevent excessive lubricant, and remove aluminum oxide shell and corrosive dirt in time, which can effectively prevent aluminum products from blistering and peeling, and reach the quality index.