This property details a material’s resistance to breaking under tension. 6061-O aluminum has a tensile strength of around 124 MPa (18,000 psi), 6061-T4 has around 241 MPa (35,000 psi) and 6061-T6 has around 310 MPa (45,000 psi).
The aluminum industry includes many distinct alloys with different characteristics and applications. 6061 aluminum is one variant of these many alloys. This material sometimes receives the name “structural aluminum” because it is ideal for many applications where strength is essential.
This aluminum alloy is a common material for many industrial applications. 6061 aluminum is widely available and has unique characteristics that allow wide use across many industries and building processes. This aluminum composite is a wrought alloy. This means the alloy contains high levels of aluminum and low levels, usually around 4%, of other alloying elements. The high level of aluminum makes the alloy more workable. Alloys with higher percentages (up to 22%) are more brittle and harder to form into shapes.
The material was initially developed in 1935 and named Alloy 61S. The number currently used to describe this alloy is a four-digit code created by the Aluminum Association. Each digit of the code represents a particular characteristic of this alloy. As part of the 6XXX alloys, 6061 aluminum primarily uses magnesium and silicon in its construction. Other alloy groups use different elements as their major alloying partners. For example, the 3XXX group primarily uses manganese.
The second digit used by the Aluminum Association describes the degree of impurity control. A “0” indicates commercial aluminum with no care taken for impurities. If 6061 aluminum were modified for impurities, 6161 would indicate the first modification, 6261 the second modification and so on.
The last two numbers in 6061 aluminum together represent the specific alloy. If either number changes, this indicates an entirely new alloy. It would still fit under the 6XXX alloys but contain different alloying elements or varying concentrations, giving it distinct properties.
The 6061 aluminum alloy is available in several different tempers. These tempers are heat-treating processes that change specific mechanical properties of the metal. Here are a few common variations of this alloy:
6061 aluminum contains 97.9% aluminum, 0.6% silicon, 1.0% magnesium, 0.2% chromium and 0.28% copper. The metal alloy has a consistent density of around 2.6 g/cm3 (0.0975 lb/in3). Due to its unique composition of elements, 6061 aluminum has specific properties. This metal category is heat treatable, easily formed, weldable and good at resisting corrosion. These combined characteristics make it an ideal alloy for many applications. While certain properties like density and composition stay the same, this alloy’s various tempers have different mechanical properties. Several of these changes in critical mechanical properties for some standard 6061 aluminum types include:
This property details a material’s resistance to breaking under tension. 6061-O aluminum has a tensile strength of around 124 MPa (18,000 psi), 6061-T4 has around 241 MPa (35,000 psi) and 6061-T6 has around 310 MPa (45,000 psi).
This metric determines the amount of stress needed to move from elastic behavior — the material returns to its original form — to plastic behavior — it stays changed. The alloy 6061-O has a yield strength of around 55 MPa (8,000 psi), 6061-T4 aluminum has a yield strength of around 145 MPa (21,000 psi) and 6061-T6 has a yield strength of around 276 MPa (40,000 psi).
This mechanical property measures the extension of a material under stress. The metric is expressed as a percentage of the original length. 6061-O aluminum has a typical elongation of around 25%. The other alloys, 6061-T4 and 6061-T6, have elongation typical measures of around 22% and 12%, respectively.
Those who use aluminum alloys as building materials must also consider the metal’s corrosion resistance properties. An oxide layer forms when this alloy is exposed to air or water. This outer oxide layer protects the inner material from corrosion. When exposed to alkaline soil, the material may also suffer from deterioration in the form of pitting. Since 6061 aluminum contains copper, it has less corrosion resistance than other alloys, such as 5052 aluminum.
While the material corrodes in contact with air, water and alkaline soil, it has strong corrosion resistance against concentrated nitric acid, ammonia and ammonium hydroxide. You can also reduce corrosive effects by coating 6061 aluminum with a protective layer. Unlike certain alloys, this one responds well to such treatment.
6061 aluminum is one of the most widely used alloys because its physical and mechanical properties make it useful for many general-purpose applications. The material’s high strength and corrosion resistance make it ideal for motor vehicles and architectural and structural uses. The alloy also forms electronic parts and chemical equipment. This alloy’s other applications include:
If your industry uses this aluminum alloy, you can rely on expert advice from HARBOR Aluminum Intelligence. Our specialized aluminum research firm compiles aluminum industry intelligence and market insight to provide expert advice to hundreds of aluminum industry clients across the globe. To learn more about current industry data concerning 6061 aluminum, subscribe to Daily Market Insights. You can receive up-to-date alerts concerning price, demand, supply and other aluminum industry data points. Our insights and expert advice will allow you to make the most informed decisions for your business.
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