What is the difference between 6061 T5 and T6 in the aluminum plate?

The 6 series aluminum plate is an aluminum-magnesium silicon alloy, and its representative grades are 6061, 6063 and 6082. Unlike other seven series aluminum plates, the 6 series aluminum plates are mainly in the T state, with the most being T5 and T6 states. There is only one word difference. What is the difference between these two states?

Before explaining the difference between 6061 T5 aluminum plate and 6061 T6 aluminum plate, users must first understand the following two terms:

Aging: The process of eliminating internal stress in metals.

Quenching: The metal is heated to a certain temperature and suddenly cooled to meet the required hardness. 2, 6, 7 series aluminum plates can be strengthened by quenching.

  • The T5 state means that the aluminum sheet is extruded from the extruder, and then air cooled to quickly reduce the temperature to achieve the required hardness (the Webster hardness is 8-12).
  • The T6 state means that the aluminum plate is extruded from the extruder and then cooled with water to immediately cool the aluminum plate, so that the aluminum plate reaches a higher hardness requirement (higher than 13.5 hardness).

The use of air cooling to cool down is relatively long, usually 2-3 days, we call it natural aging;

The water cooling time is very short, we call it artificial aging.

The main difference between the T5 and T6 states is that the strength of the T6 state is higher than that of the T5 state, and other aspects of the performance are similar. In terms of price, due to the difference in production technology, the price per ton of T6 aluminum sheet is higher than that of T5.

What is the elimination of internal pressure ?

During the production process, the density of the aluminum plate is uneven due to heat and extrusion, and the energy is not completely released, and it accumulates inside the aluminum plate. This energy is called internal pressure. Some users’ production processes (such as heating, bending, deep drawing, stretching, etc.) will release the internal stress of the aluminum plate, causing the aluminum plate to bend, wave patterns, and surface unequal. Therefore, the internal stress of the aluminum needs to be released first.

The process of eliminating internal pressure is very simple. After the aluminum plate descends along the assembly line, the manufacturer will add a process where the machine will stretch the aluminum plate to release the energy in the aluminum plate.

The state of the aluminum plate used to eliminate internal stress is represented by the number Tx51, for example: 6061 T651, 6082 T651.