The Aluminum Association’s four-digit designation system is a standardized method used primarily in North America to classify wrought aluminum and its alloys. The number 1100 designates commercially pure aluminum, meaning it is not intentionally alloyed with elements to increase its strength. This grade maintains a minimum aluminum content of 99.0% by weight.
The 1xxx Aluminum Classification System
The four-digit code conveys specific information about the metal’s makeup. The first digit identifies the main alloying group; “1” in 1xxx indicates the material is essentially pure aluminum, with a minimum purity of 99.0%. For 1xxx series alloys, the last two digits relate to the minimum percentage of aluminum purity above 99.0%. For instance, 1060 indicates a minimum aluminum content of 99.60%.
The second digit in the 1xxx series, such as the first “1” in 1100, signifies variations in impurity limits or minor alloying elements. Aluminum 1100 is a specific grade within the pure aluminum family, often containing trace elements like copper, iron, and silicon. This high-purity commercial grade is distinct from other alloy families that use major elements like copper (2xxx) or magnesium (5xxx) for strengthening.
Defining Characteristics of Aluminum 1100
Aluminum 1100’s composition dictates its defining physical and chemical attributes. Its high purity results in exceptional resistance to corrosion, particularly in atmospheric conditions and against chemical attack. This resistance stems from the naturally-forming, highly stable aluminum oxide layer on the metal’s surface.
The material is considered non-heat-treatable, meaning its strength cannot be enhanced through thermal processing.
The trade-off for its purity is relatively low mechanical strength, making it one of the softer aluminum grades. Typical tensile strength ranges from 110 to 150 megapascals in certain tempers. This softness translates into high ductility and excellent formability. It can be easily cold-worked using methods like spinning, deep drawing, and stamping to create intricate shapes. Furthermore, Aluminum 1100 exhibits high thermal and electrical conductivity, second only to copper among common metals.
Primary Industrial Applications
Aluminum 1100 is the preferred choice when purity and workability are prioritized over high structural strength. Its superior corrosion resistance and non-toxic nature lead to widespread use in the food and chemical processing industries. Applications include manufacturing food containers, cooking utensils, and equipment for handling chemicals and pharmaceuticals.
The alloy’s excellent thermal conductivity is leveraged in heat transfer applications, such as fins for heat exchangers and heat sinks for electronic devices. Its high formability and attractive surface finish also make it suitable for decorative purposes, including architectural trim, nameplates, and light reflectors. The soft nature of 1100 allows it to be easily rolled into very thin gauges, making it a common material for household foil and certain types of packaging.