The contribution of aluminum alloys to the bicycle industry is obvious to all. As the design of aluminum alloys has become more diversified and the processing technology has been improved, the dependence of bicycle materials on aluminum alloys will become larger and larger. there is no end to market space.
The frame made of aluminum alloy is light and low price is its advantage. However, from the "light" point of view, the current difference with the iron material is not large. The old rider responded to it as "light but flexible." Although many improvements have been made, the disadvantages of low Young's modulus of elasticity have never been overcome. In recent aluminum alloy frames, in order to increase the Young's modulus of elasticity, increase the outer diameter of the pipe, use a flat tube, or heat-treat the aluminum tube, etc. Producing a lightweight and rigid frame, this latest aluminum frame is lightweight and rigid enough for the rider.
The aluminum alloy is an alloy in which a metal such as Mg, Zn, Si, or Cu is added to pure aluminum. Aluminum itself has the advantages of light weight, good plasticity, corrosion resistance, etc., and the addition of other metals significantly improves the mechanical properties. Most of the aluminum alloys used in bicycles are 6000 series (Al-Mg-Si) and 7000 series (Al-Zn-Mg-Cu). After heat treatment (aluminum is resistant to high temperatures and can change properties at high temperatures), it can be made into a variety of materials.
The 6000 series is considered to be a material that is resistant to corrosion, strength, and weldability. The most used is the mechanical strength of the 6061 aluminum alloy.
The 7000 series is the strongest material in aluminum alloys. In particular, the
7075 aluminum plate is a super-hard aluminum (material for manufacturing aircraft), but it is difficult to weld and has poor corrosion resistance (will be white).
Advantages of aluminum alloy bicycle frame：
(1).It can make a lightweight frame
Aluminum is light in weight but not hard enough to be made into an aluminum alloy for heat strength and heat treated. Many aluminum alloy frames are made of
6061 T6 aluminum plate. The T6 mark indicates heat treatment and aging. If there is no heat treatment, the strength can only reach 1/2, or 1/5.
In addition,
7005 aluminum plate is also commonly used to manufacture the frame, its strength is not as high as 7075, However, it is also a material that can perform sufficient aging at normal temperature.
(2) The appearance of long-term use does not change much.
Aluminum itself is a metal that is easily corroded. There is almost no aluminum that is not oxidized in the air, and it is immediately oxidized in the air to form a very thin oxide film. Why not rust? The reason is that the oxide film is prevented from continuing to rust when it reaches a certain level. The oxide film is almost colorless so that it is not easy to find changes in appearance (sometimes it is whitish). On the other hand, when riding a bicycle made of this material, the more the number of rides, the higher the number of stresses, and the significant change in strength. Recently, in order to achieve light weight, many frames are made of thin materials (the degree of thinness has reached the limit).
Disadvantages of aluminum alloy bicycle frame：
1) Aluminum is a material with low modulus of elasticity and low rigidity. Therefore, thick pipes are used, or shapes such as cross-over pipes, padded pipes, and the like are changed.
2) Need heat treatment. Heat treatment is necessary, otherwise the strength is not sufficient. Therefore, the general scale of the factory is incapable of purchasing heat treatment equipment. Especially the 6000 series aluminum alloy tube. Each manufacturer of heat treatment indicators is considered confidential. This also results in a variety of hardness.
