Visual inspection can also determine the quality of the profile. The main aspects to check are as follows:

(1) First, check the wall thickness of the profile. Thin-walled profiles should not be used.

(2) Check the flatness of the profile surface. For hollow profiles, check for dents and bulges on all four sides.

(3) Check each 6-meter section of the profile for obvious twisting. Excessive twisting is unacceptable because during aluminum window casting, the profile is straightened, leaving residual torsional stress inside the window.

(4) Check the profile surface for open bubbles (white spots) and slag (black spots).

(5) The profile surface should not have cracks, burrs, peeling, or corrosion.

(6) The profile surface should not have obvious scratches, dents, or dents.

(7) The profile should be bent by both hands. Good twisting strength is desirable; it should spring back after being released. It should not be too soft; a "noodle-like" shape should never be used.

(8) Two different shades of the same profile are not allowed.

(9) Place several profiles together and observe the color difference. If the color difference is large, it is not suitable for use.

(10) Lightly scratch the surface of the profile with a smooth, hard object (iron). If a white scratch is left on the surface and can be wiped off by hand, it means the oxide film has not been removed. If the white scratch cannot be wiped off by hand, the oxide film has been scratched off, indicating poor oxide film adhesion, a thin oxide film, and poor aluminum oxidation quality.

The quality of aluminum is related to many factors. The above is a very simple and easy-to-understand introduction, mainly to provide users with a preliminary basis for selecting aluminum materials and to avoid being deceived. When purchasing materials, check the test report. Don't listen to the salesperson's empty promises and be greedy for cheap prices. This can easily lead to the purchase of substandard aluminum materials, causing hidden dangers to the building.

(11) Hollow profiles with blue, green, or yellow discoloration in the core wall are all considered scrap aluminum.