Known bicycle materials （6）

Al alloy (Al and Mg - - - - the Si Zn Cu (Mg) -
7005,7075 alloy of mechanical properties
Name of alloy heat elongation (MPa) intensity endurance
(MPa) fatigue strength, elongation (MPa)
(E)
(GPa)
7005 T53 345 305 130
7003 (10)
(7003)
7075 0 230 107 163 17 74
T651 T6, 526 163 11 74 5.97

Adopts aluminium alloy frame

(1) can make light of the frame
The proportion of aluminum but not light, in order to enhance the strength of hard alloy and made it to heat treatment. Heat treatment method, the limitation of precipitation enhancement by simply, in metal forming a block in the metal material deformation. In some high temperature heat, will cause ageing, if not after the program frame, also can cause normal aging. The frame is placed in the room will be increased.
Many al-alloy frame with 6061T6 material to make. Mark said after heat treatment, introducing T6 limitation. If there is no word to heat intensity can only 1/2, or 1/5 levels.
The bicycle parts are 7075 marks (e.g. XTR crank, etc.), strictly without treatment. That is because there is no limitation, so normal aging. 7075 alloy was necessary for heat treatment, heat treatment can be increased by 5 times the strength.
In addition, 7005 alloys are also used to manufacture frame, its strength, but it can 7075 at room temperature can also plenty of time. This material is made of thin Padded available. But the strength of material itself and the young modulus is low, so bold to improve the rigid pipe diameter. Usually called aluminum coarse pipe are of this type.
(2) for a long time did not change incorporating aluminum itself is very easy, the corrosion of metal by almost nonexistent in air is not the aluminum oxide, placed in the air once formed by oxidation of oxide film is very thin. Why not rust? Reason is the oxide film reaches a certain level to prevent rust. The film is a colorless, so look almost can't change (sometimes white).
On the other hand, ride bicycle when the materials manufacturing, ride, the more stress and high strength, also caused significant changes. Recently, in order to seek a lightweight, many frame to use thin thin has reached the level (limit). These are not used to the limit of fatigue aluminum frame, after a long time strength will be how to change! Dedacciai company production SC61-10 is surface has shot peening hardening processing (KET), the purpose is to extend the processing of fatigue life. According to the data, and can improve public pre-vaccine period. Handle: fatigue, KET destroying is in what happens on the metal surface crack, so as to improve the hardening processing technology with metal surface hardness.
Adopts aluminium frame faults
1) aluminum is elastic and rigid low materials. Therefore using the pipeline, or change the coarse as cross - over tube, padded pipe, etc.
(2) need to heat
For the heat treatment, or insufficient strength. Because of the small size of the general plant without ability buy heat treatment equipment. Especially, the 6,000 mostly aluminium tube heat pipe factory specified conditions.