The most important properties of an aluminum alloy, which determine its manufacturability and application prospects, are compressibility (pressure and pressing speed), sensitivity to hardening and its strength characteristics. The technological and strength properties of the most popular aluminum alloys of the 6xxx series are presented in the tables.
When choosing an aluminum alloy, it is necessary to take into account the conditions of its end use. If the end user specifies any special properties, then manufacturer of extruded aluminum profiles (“presser”) can offer the most suitable alloy, as well as optimize technological parameters to ensure them.
Aluminum alloy 6060 - Aluminum alloy AD31
The alloy with the highest compressibility (ease of pressing) and the lowest sensitivity to hardening is the “European” aluminum alloy 6060 due to the lowest concentration of alloying elements. Following it is its “American” analogue - aluminum alloy 6063 (our AD31).
Although the strength properties of these alloys are very moderate compared to alloys such as 6061 (AD33) and 6082 (AD35), they are quite adequate for building envelopes (windows, doors, translucent facades). Alloy 6063, which is somewhat stronger due to its higher magnesium content than alloy 6060, is also used in building structures that are not overly loaded.
Aluminum alloy 6005A
The next level in strength is given by aluminum alloy 6005A from the 6005 alloy family. Unlike the base alloy 6005, it has a range from 0.12 to 0.50 % of the total concentration of chromium and manganese, which ensures an increase in toughness properties. This aluminum alloy has a good combination of fairly good compressibility, not too much sensitivity to hardening and improved mechanical properties. The pressing speed of this alloy is two times lower than that of the “softest” alloy 6060 and only slightly lower than that of the “harder” alloy 6063, and the minimum strength in the T5 state is the same as that of the 6061 alloy in the T6 state. The minimum quenching rate, in turn, is half that of medium-strength alloys 6061 and 6082, which means that press quenching of 6005A alloy profiles often requires only air cooling, instead of air-water or water cooling, which is usually required for quenching alloys 6061 and 6082.
Aluminum alloy 6061 - Aluminum alloy AD33
Aluminum alloy 6061, the next most popular of the 6xxx series alloys after alloys 6060/6063. Although alloy 6061 has fairly high strength properties, it is relatively difficult to press compared to alloy 6005 and even the stronger alloy 6082.
Aluminum alloy 6082
Aluminum alloy 6082 has the highest strength properties of all the 6xxx series alloys and, at the same time, exhibits good compressibility, at least compared to alloy 6061.
Comparison of alloys 6060, 6063 and AD31
The chemical composition of aluminum alloys 6060 and 6063 according to EN 579 and alloy AD31 according to GOST 4784 is shown in Table 1. In the old German DIN standards, alloys 6060 and 6063 were designated AlMgSi0.5 and AlMgSi0.7, respectively
The role of magnesium and silicon
Magnesium and silicon are the main alloying elements in 6xxx aluminum alloys. Magnesium and silicon are included in the magnesium silicide (Mg2Si) compound in a ratio of 1.73 to 1. It is the magnesium silicide particles that make 6xxx aluminum alloys thermally hardenable. The level of strength properties of these aluminum alloys depends mainly on the number, size and uniformity of the distribution of Mg2Si particles in aluminum.
Alloys 6063 and 6060
6063 aluminum alloy was developed in the 1930s. In the 1990s, a “diluted” version of it, aluminum alloy 6060, appeared. Currently, 6063 alloy is sometimes called “American” and is widely used in the United States. In Western Europe, alloy 6060 is used - a kind of “European” version of alloy 6063. The diagram above shows that alloys 6060 and 6063 overlap at low magnesium content and excess silicon. This is the main property of alloy 6060 and its main difference from alloy 6063.
Alloys 6063 and AD31
Aluminum alloy AD31 was developed in the USSR (or borrowed) in the same 1930s. Its chemical composition is determined by GOST 4784-97. Until 2000, alloy AD31 was identical to alloy 6063. Since 2000, alloy AD31 according to GOST 4784-97 has ceased to be identical to alloy 6063: the tolerances for impurities have expanded significantly, primarily for iron: from 0.35 to 0.5.
Alloys 6060 and AD31
The differences between alloy 6060 and alloy AD31 are basically the same as from alloy 6063. Alloy AD31 according to GOST 4784-97 additionally has a higher iron content: up to 0.5 %.
Comparison of alloys 6060 and 6063
Aluminum alloy 6060
6060 aluminum alloy has a minimum magnesium content of 0.35 % and silicon content of 0.30 %. In T5 condition it provides pressed profiles (up to 3 mm thick) with a minimum strength of 190 MPa. Easily pressed even with very complex profile cross-sections. It has good formability, for example when bending, in the T4 condition - after hardening and natural aging.
Aluminum alloy 6063
6063 aluminum alloy has a minimum magnesium content of 0.45 % and a minimum silicon content of 0.20 %. The increased minimum of magnesium compared to alloy 6060 provides a slightly higher guaranteed strength than that of alloy 6060: in the T5 state - up to 215 MPa. However, the increased magnesium content reduces the pressing speed of alloy 6063 - by 15-20 % compared to alloy 6060.
Aluminum alloy 606035
The aluminum giant HYDRO has long been using and supplying consumers with its own internal alloys, which are narrowed versions of the main alloys of the 6xxx series. It satisfies the chemical composition of both the requirements of alloy 6060 and alloy 6063. This alloy provides, in the T5 state, a tensile strength of at least 215 MPa, a yield strength of at least 190 MPa, and an elongation of at least 10 %. These mechanical properties meet the requirements for extruded sections in T5 condition for both Alloy 6060 and Alloy 6063.