Production of the bicycle frame material chromium molybdenum steel, aluminum, titanium, carbon fiber and the like. Which used to produce the thinnest tube is chrome-molybdenum steel frame. Its workability is good, cheap materials, Riding feeling good, but it must be made of thin-walled tubes, thin-walled tube there is such a high tensile strength and workability.
Strength chrome-molybdenum steel is easier to gradually weaken, which is easier to fatigue phenomena seen in the following.
(1) The same impact force applied to a variety of materials, the maximum stress (prone to damage caused by fatigue) chromium molybdenum steel thin tube occurred.
(2) a long history of research on chromium-molybdenum steel, the maximum limit use of its features made extremely thin-walled tubes, each local site, although stress occurs, but for the entire tube is higher stress will occur .
(3) Comprehensive corrosion caused by the rust will cause changes in the pipe wall, the result of this phenomenon and increase the stress caused by fatigue damage.
(4). In the local stress concentration and rust, or recess caused by trauma, causing fatigue failure from there.
(5) The shock generated when the race to make the frame a high stress occurs, the more the frequency of use of fatigue damage is gradually increasing.
Above is mainly for chromium-molybdenum steel, aluminum alloy frame but the rapid development, there are many thin-walled aluminum tube frame production, whether they are above-chromium-molybdenum steel frame, like fatigue damage it? Especially aluminum no fatigue limit, minimal stress is bound to cause damage. The greater the damage to the stress, the shorter the time required. Extremely thin-walled aluminum frame tubes sold, none of the manufacturers clearly indicate its life.