1. Cause analysis
Industrial aluminum extrusion temperature is too low, extrusion speed is too slow, profile in the extruder outlet temperature is less than the solid solution temperature, play no solid solution strengthening role;
Less fans at the outlet of the profile, the air volume is not enough, resulting in a slow cooling speed, can not make the profile in a short time to fall below 200℃, so that the thick Mg2Si precipitate out too early, thus reducing the solid solution phase, affecting the mechanical properties of the profile after heat treatment;
(3) ingot composition is not qualified, the content of Mg and Si in the ingot is not up to the standard requirements;
(4) the ingot is not homogenized, so that the precipitated Mg2Si phase in the ingot tissue can not be extruded in a short time to re-solid solution, resulting in insufficient solid solution and affect the performance of the product;
Improper aging process, poor hot air circulation or incorrect thermocouple installation location, resulting in insufficient or over aging.
Reasonable control of extrusion temperature and extrusion speed, so that the profile in the extruder outlet temperature to maintain the solid solution temperature above;
Enhanced air cooling conditions, conditions of the factory can be installed atomization cooling device, in order to meet the requirements of 6063 alloy cooling gradient;
(3) strengthen the quality control of ingots;
(4) conduct homogeneous treatment of the ingot;
(5) determine the aging process, the correct installation of thermocouples, the correct placement of profiles to ensure smooth hot air circulation.