[China Aluminum Industry Network] To identify the advantages and disadvantages of aluminum doors and windows, there are six main aspects of material materials can refer to: 1. Thickness: Aluminum alloy sliding doors are available in 70 series and 90 series. The aluminum alloy sliding door in the house can be used with 70 series. The series number indicates the thickness of the door frame thickness in millimeters. Aluminum alloy sliding window has 55 series, 60 series, 70 series, 90 series four. The series selection should be based on the size of the window hole and the local wind pressure value. Aluminum sliding windows used as closed balconies should not be smaller than the 70 series. 2. Strength: Tensile strength shall be 157 Newtons per square meter and the yield strength shall be 108 Newtons per square millimeter. When you buy, you can use your hands to bend the profile moderately, and you should be able to recover after loosening your hands. 3. Color: The same aluminum alloy color should be the same, such as the color difference is obvious, that is not suitable for purchase. 4. Flatness: Check the surface of aluminum alloy profile, there should be no depression or bulging. 5. Gloss: aluminum alloy doors and windows to avoid the purchase of surface bubbles (white spots) and ash (black spots), as well as cracks, burrs, peeling and other obvious defects in the profile. 6. Degree of oxidation: The thickness of the oxide film should reach 10 microns. When you purchase, you can lightly stroke the surface of the profile to see if the oxide film on the surface can be wiped off.