Aluminum alloy is a kind of metal which has lightweight and low price. A frame making from AL6061 has high durability and can be against corrosion. It also can be lengthened and laminated slimly to have the most lightweight but still be high durability. After completing, the frame will be heat treatment to maximum hardness which helps the bike to under pressure well.
There are two aluminum types used a lots to produce the frame of the bike: AL6061 and Al7005. Both of them have the same composition but the different ingredient.
AL7005
In terms of characteristics, aluminum 7005 has very high hardness and durability, higher than aluminum 6061. However, although aluminum 7005 has high hardness and durability, it is difficult to shape the tube and difficult to weld. The heat treatment process of the aluminum is also complicated. Due to the above problems, it takes longer time to create the 7005 aluminum frame than the 6061 aluminum and the cost will also increase much higher as well.
Due to tough, hard-formed and hard-wearing properties of the 7005, it limits the design concept of the bike. To be able to make the frame from aluminum 7005, the manufacture need to machines to handle this aluminum and these machines are not cheap.
Al6061
There are three types of aluminum 6061:
- 6061-O is a weak and soft aluminum aloy without the heat treatment process. So it is easy to shape the tube.
- 6061-T4 is a heat-treated alloy and have 2 times stiffness as 6061-O.
- 6061-T6 is a T6 heat-treated aluminum with a harder than T4. The frames will be processed the T6 heatment to get the hardest.
This is an aluminum type that is highly valued by bicycle frame manufacturers due to its high hardness but easy to shape. The elongation of 6061 is better than the 7005. Moreover, the cost of this luminum is low but its quality is good.
Non-heat treated aluminum pipes will be shaped the frame. Once the frame has been welded done, it will be treated the t6 heatment so that the aluminum will be hard and durable.
In addition, the 6061 It has good mechanical properties, good weldability, suitable for connecting and welding tubes on the frame. There are other types of aluminum but the price is too expensive should not be selected.