Preparation method of light bicycle frame with high strength and low density

Abstract

The invention relates to a preparation method of a light bicycle frame with high strength and low density. The method comprises the following steps: (1) preparing a magnesium alloy ingot; (2) annealing after machining of the magnesium alloy ingot; (3) carrying out forward extrusion preparation; (4) extruding the magnesium alloy ingot obtained in step (3) to obtain a profile and dragging; (5) carrying out backward extrusion preparation; (6) extruding the magnesium alloy ingot obtained in step (5) to obtain a profile and dragging; (7) cutting the profiles obtained in step (4) and step (6); (8) machining a product obtained in step (7), then quenching, carrying out aging treatment, and then naturally cooling to room temperature to obtain a pipe; (9) carrying out treatment and heat preservation on the pipe obtained in step (8); and (10) machining the pipe obtained in step (9) after welding, heat treatment and cooling to obtain the product of the bicycle frame. The preparation method is simple in process and easy to implement, and the obtained product can solve the problem of compatibility of strength and weight of the bicycle frame to the greatest extent.

Description

technical field [0001] The invention relates to the technical field of metal material preparation, in particular to a method for preparing a high-strength, low-density lightweight bicycle frame. Background technique [0002] At present, bicycles are a huge industry that is inseparable from the development of human society. For more than 200 years, human beings are still inseparable from bicycles, because bicycles can not only travel but also keep fit, and they are ideal means of transportation for short-distance travel. With the progress of society, human beings have attached great importance to the protection of the natural ecological environment and the concept of "life lies in movement", which has set off an unprecedented tide in the 21st century, and its industrialization will have a great impact on human society. The extremely far-reaching impact will inevitably bring huge economic value and huge benefits in the industry. [0003] As the most important part of a bicycl...

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Problems solved by technology

[0005] ⑴Magnesium alloy materials have poor fluidity during the extrusion process. If the temperature and speed are not controlled accurately, it is very easy to have incomplete mold filling, especially the extrusion speed.

When the deformation speed increases again, although the temperature rise of the blank is obvious, because the work hardening speed of the metal during the deformation process is faster than the recrystallization softening process, the flow stress of the billet not only does not decrease, but increases significantly, so that the extruded The shape of the profile is defective and cannot meet the standard

[0006] (2) Metal magnesium has a close-packed hexagonal structure, so the plastic deformation ability of magnesium alloy is poor. At high temperature, twin crystal slip is easy to occur, and the plastic deformation ability is improved. However, if the temperature is too high, the grain growth will be caused, and the plastic deformation ability will be reduced. and will affect the strength of the product

The magnesium alloy bicycle frame involved in the present invention is composed of pipes with different diameters and wall thicknesses. The thinnest pipe has a wall thickness of only 1.8mm. During the extrusion process, the extrusion ratio is very large, and there is great friction between the material and the mold. During the extrusion process, it will generate very high heat, which makes it difficult to control the temperature during the extrusion process, resulting in easy skinning, tearing, and rough surface of the product, which affects the quality

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