Known bicycle materials （5）

MuGang chromium Fe (Mo) - Cr -

In the 100 years history of bicycle, iron materials is rigid and weight are balanced ideal material. The biggest characteristic of iron frame is available in various ingredients, various thicknesses steel, the thickness of the steel needed to choose to accelerate. So can choose the most suitable size, rigidity, riding a feeling for the number of frames, the difference is sensitive to the mm old drivers are very good. It's the biggest drawback is heavier than other materials (past). But recent iron frame after heat treatment, the material made of thin pipe, tube to use its weight loss to light alloy will.
MuGang chromium alloy is chromium, mo. It is as follows:
Well, quenching.
The processing of tempering, resistance.
2008 temper brittleness tendency.
Nature is good, high temperature, after processing.
Well, welding.
(the right picture) MuGang BRIDGESTONE ANCHOR chromium frame, the company's advertising is "and" as light alloy system, the price is about 6,700 (left), (right), 5,000 yuan.
The advantages of MuGang chromium adopts frame
(1) processing
Chromium MuGang frame is the oldest frame, so it is the longest time. Now the required strength can be extremely thin frame of pipeline.
(2) the shock absorption capability
Riding a feeling extremely good, such as "like a spring" ride. Constitute the MuGang chromium pipe frame shock absorption is excellent performance.
(3) welding easily
MuGang chromium than titanium, aluminum soldering easily. Can design a shape of fame. In addition, also do not need to heat treatment after welding, so don't need big heat treatment equipment, and low cost.
(4) cheap price
Although some high chromium MuGang frame of expensive, but generally cheap price. Also, use cheap price to buy high times frame.
Responding to MuGang chromium frame faults
(1) are easy to rust
With the MuGang chromium frame containing cr, but add less (stainless steel contains of 12% chromium alloy iron). If not have, have surface treatment of wounds are easy to rust. But generally have antirust processing. The bicycle, pipe, rust thin after the flesh of the impact will be very big. Rusty meat, reduce pressure and decrease (intensity of stress concentration).
(2) metal fatigue stress concentration caused significant (metal fatigue),
If use meat thin chromium MuGang frame requiring attention! Of course this phenomenon any metal fatigue can include aluminum metal. Metal fatigue phenomenon simply said, although it can prevent metal plastic deformation of small power, but repeated pressure stress, metal could be destroyed (called subtle stress concentration). Aircraft crashed, and sometimes also a part of the metal fatigue. On bicycle, because the metal fatigue strength of the members may not keep. For example, when the impact on DH shortened lifespan of bicycles. If you feel when trample a move likely is already fatigue metal.
Welding parts, such as (maternal) from the pipeline to dissolve the harmony of the site (dissolution), crystallization properties will change significantly. To make these organizations homogenization, should again crystallized after detailed contents (of). But the large frame processing, on the other hand, this process that has cool again, make the intensity of variable enhancement pipeline.
Because of this reason, when welding methods used for processing. If use low temperature welding methods frame. Whether any good welding and welding parts (1000 ° C) and the other side (room) pipeline, the temperature difference between cooling shrinkage and residual stress. This site is the stress concentration, might crack. Results the cycling long may cause metal fatigue, micro hardening processing also makes the shock absorption became worse.