There are many factors that affect forged aluminum alloys. Today, the editor mainly wants to share with you the two major reasons for deformation speed and deformation degree. The details are as follows.
The deformation speed does not have much influence on the properties of most aluminum alloys. Only some highly alloyed aluminum alloys have a significant decrease in plasticity when they are deformed at high speeds. In addition, when the low deformation speed transitions to a high deformation speed, the deformation resistance increases by about 0.5 to 2 times depending on the alloying degree of the alloy. Therefore, aluminum alloy forging can be performed at either a low deformation speed or a high deformation speed. However, in order to increase the allowable degree of deformation and improve production efficiency, reduce deformation resistance and improve the closeness of mold filling, it is better to use presses and die forging to forge aluminum alloys than hammer forging. This is especially true for large aluminum alloy forgings and die forgings.
When the aluminum alloy is die forged on a high-speed hammer, due to the large deformation speed, large internal friction, and large thermal effects, the temperature rise of the alloy during forging (about 100°C) is relatively obvious. For this reason, the initial forging temperature of the aluminum alloy should be adjusted, and the heating temperature of the blank before forging should be selected to be the lower limit of the originally specified initial forging temperature. In addition, due to the large external friction coefficient and poor fluidity of aluminum alloys, if the deformation speed is too fast, it is easy to cause defects such as peeling, folding and uneven crystal structure of the forgings. For high-strength aluminum alloys with low plasticity, it is also easy to cause forging cracks. Therefore, this type of aluminum alloy is more suitable for forging on low-speed presses.
