Aluminum Tube Specifications

Characteristics of Aluminum

• Pure aluminum is malleable and has a lower strength than steel. Its tensile yield strength is 1450 psi, its ultimate tensile strength is 6530 psi and its shear strength is 4930 psi. Its elongation at break is 50 percent in a 2 inch sample, 1/16 inch thick. Its resistivity is 0.00000270 ohm-cm which makes it an excellent conductor. It heats up quickly with a specific heat capacity of 0.215 BTU/lb-°F, conducts heat well with a thermal conductivity of 1690 BTU-in/hr-ft²-°F and has a very high melting point at 1220 °F. Aluminum tubes with these characteristics are used in aerospace, food processing, food storage and structural applications.

Round Tube Sizes

• Aluminum tubes are available in a wide variety of sizes and shapes. Commonly available round tubes range from an outer diameter of 5/8 inch to 16 inches and wall thicknesses of 1/16 inch to 1 inch. Generally, only round tubes with wall thicknesses up to 1/8 inch are available as coiled tube.

Rectangular Tube Sizes

• Rectangular and square tubes are not available in as many sizes as round tubes. Square tubes may be from 3/4 inch to 8 inches a side with a wall thickness of 1/16 inch to 1/2 inch. Rectangular tubes may have sides from 1/2 inch to 6 inches with the smallest being 1/2 inch by 1 inch and the largest 6 inches by 4 inches. Their wall thickness ranges from 1/8 inch to 1/2 inch.

Aluminum Tube Alloys

• The major problem of pure aluminum tubes is their lack of strength. The strength of aluminum can be increased by about 20 percent with the addition of small amounts of other elements. Many of the other characteristics of pure aluminum can also be improved in this way. Tubes made from aluminum alloys carry a material number which is made up of four digits. The first digit gives the main alloying element with 1 being pure aluminum, 2 copper, 3 manganese, 4 silicon, 5 magnesium, 6 magnesium and silicon, 7 zinc and 8 other elements with 9 unused. The second digit identifies a modification or addition to the major alloying element and the remaining two digits identify the various alloys available. If a particular pure aluminum tube does not meet the specification required for an application, it may be possible to meet the specification by using one of the aluminum alloys instead.