Aluminum strips are classified into different grades based on their alloy composition, mechanical properties, and applications. Common grades include 1000 series (99% pure aluminum), 3000 series (aluminum-manganese alloys), 5000 series (aluminum-magnesium alloys), and 6000 series (aluminum-magnesium-silicium alloys). Each grade has specific characteristics, such as corrosion resistance, formability, and strength, making them suitable for various industries like construction, automotive, and packaging.