Forged aluminum alloy rear fork is widely used in many high-end bicycles and some motorcycles. Its forging process parameters directly affect product quality, especially the formation of internal defects. In-depth analysis of the relationship between the two is crucial for producing high-quality forged aluminum alloy rear fork.
The main forging process parameters of forged aluminum alloy rear fork include forging temperature, forging pressure, deformation speed and forging ratio. Forging temperature affects the fluidity and forgeability of aluminum alloy; forging pressure determines the degree of deformation of the metal and the ability to fill the mold cavity; deformation speed has a significant effect on the stress-strain distribution inside the material; forging ratio is related to the degree of deformation from raw materials to the final product.
If the forging temperature is too high, the aluminum alloy may overheat or even burn. Overheating will make the grains coarse and reduce the mechanical properties of the rear fork, while overburning will seriously damage the organizational structure of the material, resulting in internal cracks and other defects. On the contrary, if the temperature is too low, the deformation resistance of the aluminum alloy increases, which is easy to cause incomplete forging, resulting in defects such as looseness inside the rear fork, affecting its density and strength.
When the forging pressure is insufficient, the aluminum alloy cannot be fully filled in the mold cavity, which may cause defects such as folding and lack of meat. These defects not only affect the appearance of the rear fork, but also become stress concentration points, causing crack propagation in subsequent use. Excessive pressure may cause excessive stress on the local part of the mold, resulting in mold damage, and may also cause excessive residual stress inside the rear fork, increasing the risk of internal cracks.
Too fast a deformation speed will cause a large inertial force and impact force inside the aluminum alloy, which is easy to cause adiabatic shear bands, leading to internal cracks. If the deformation speed is too slow, the material may cool too quickly during the forging process, and defects similar to low-temperature forging will also occur, such as incomplete forging and internal looseness.
If the forging ratio is too small, the organization of the raw material cannot be fully improved, and the original defects such as pores and inclusions may be retained inside the rear fork. As the forging ratio increases, the material structure gradually becomes finer and the performance improves. However, if the forging ratio is too large, the grains will be over-elongated along the forging direction, resulting in anisotropy and possible internal defects such as lamellar tearing.
The forging process parameters of forged aluminum alloy rear fork are closely related to the internal defects of the product. In actual production, the mutual influence of various process parameters must be comprehensively considered. By accurately controlling parameters such as forging temperature, pressure, deformation speed and forging ratio, combined with advanced detection technology, factors that may cause internal defects can be discovered and adjusted in a timely manner, so as to produce high-quality, defect-free forged aluminum alloy rear fork products that meet the performance and safety requirements of transportation vehicles.
