1. Squeeze the defect.
Aluminum extrusion process due to the extrusion equipment is complete, the extrusion process is mature and whether the operation is improper, such as bubbles, inclusions, stratification, color, distortion and other defects that affect the quality of aluminum.
2. Thin oxide film thickness.
National standards for building aluminum oxide film thickness should not be less than 10um (microns). Insufficient thickness, aluminum surface easy to rust, corrosion. There are no production name, site, production license, certificate of aluminum profile, the oxide film thickness of only 2 to 4um, and some do not even oxide film. According to the estimation of experts, every 1um of oxide film thickness can be reduced by 150 yuan per ton of section material.
3. Chemical composition failed.
Incorporation of a large number of miscellaneous aluminum, aluminum scrap aluminum can greatly reduce costs, but will lead to unqualified chemical composition of aluminum construction, a serious threat to the safety of construction.
4. Reduce profile wall thickness.
90 Series sliding window type, according to the national standard aluminum wall thickness of not less than the minimum 1.4mm, some products only 0.6 to 0.7mm. 46 Series to bombshell type, the national standard aluminum wall thickness of not less than minimum 1.62mm, sampling, some products only 0.97 to 1.18mm.
Low-quality aluminum to reduce a large number of closed time, reducing chemical loss, cost reduction, but the profile corrosion resistance is also greatly reduced.