There are primarily six aspects to consider in terms of material selection:

1. Thickness: Aluminum alloy sliding doors and windows come in two series, 70 and 90. For residential interiors, the 70 series is sufficient. The number of aluminum alloy series represents the millimeter size of the door frame thickness. Common aluminum alloy sliding windows include the 55, 60, 70, and 90 series. Selection should be based on the size of the window opening and the local wind pressure value. Aluminum alloy sliding windows used for enclosed balconies should be no less than the 70 series.

Strength: The tensile strength should reach 157 Newtons per square millimeter, and the yield strength should reach 108 Newtons per square millimeter. When selecting, the material should be slightly bent, and it should return to its original shape after releasing.

The color tone should be consistent across the same aluminum alloy profile; if there is a significant color difference, it is not advisable to purchase.

Flatness: The surface of the aluminum alloy profiles should be free of dents or bulges.

5. Glossiness: Avoid selecting aluminum alloy window and door profiles with obvious defects such as open bubbles (white spots), slag (black spots), cracks, burrs, and peeling.

Oxidation Degree: The thickness of the oxide film should reach 10 micrometers. When selecting, gently scratch the surface of the profile and check if the oxide film can be wiped off.