The Forging Process Of Titanium Forgings
1. Deformation temperature:
In the forging of titanium, the heating degree is a very important parameter, which must be strictly controlled, for the ingot. All should be selected above the a + β transition point, and then the temperature will gradually decrease with the increase of deformation fire. When forging is close to the finished product; for a. a + B alloy, there should be enough deformation below the a + β/B transformation point, at least 50% or more. For the alloy, because of its low phase transition point, the heating should basically be above a +β/transition point, and the heating time should be respected when the heating is appropriate, the shorter the better.
For forging, the heating temperature is very important, but it is more important to master the deformation temperature. The deformation temperature is affected by the operating time and the deformation speed. Although the heating temperature is appropriate, if the operation time is too long, the temperature will drop quickly and the forging process will not be completed. If the temperature rises, the performance will be destroyed. Therefore, during the forging process, operators are required to accurately control the deformation temperature.
2. Deformation
The amount of deformation is an important guarantee for obtaining a uniform and finely divided structure. Generally, at a suitable temperature, the greater the deformation, the more uniform and better the organization. For ingots, when the deformation is 70% to 80%, the casting will be basically broken. In order to obtain good forgings, it is necessary to have enough fire deformation in the two-phase zone, and the deformation per fire should not be less than 20%, in order to obtain good structure and performance.
3. Deformation speed
The higher the deformation speed, the higher the deformation heat generated. The thermal conductivity of titanium is very poor. Therefore, when the deformation speed is high to a constant speed (such as the speed of hammer forging), the forging will be locally overheated, which will cause the local structure to be changed, and even overburn, leading to the performance of the part. inferior.
The appropriate forging deformation speed is: during deformation, the temperature of the workpiece does not increase, but it does not decrease quickly, so that the workpiece can obtain sufficient deformation time at a certain temperature, and good structure and properties can also be obtained.
From the aspect of deformation speed, the forging hammer speed is too high, and the deformation heat generated during forging is very high, which is easy to cause uneven structure. Therefore, in forging, it is necessary to use experience to master the severity and speed of hammer forging. The deformation speed of the hydraulic press is about 1/30 of the vertical forging, and the deformation heat generated is much smaller. Easy to get good organization. However, the temperature of the workpiece drops quickly, so it must be operated quickly.
The deformation speed of the precision forging machine is between the forging hammer and the hydraulic press, so it can keep the workpiece at a constant temperature for a long time, so as not to cause the workpiece to heat up very high. So for forging titanium, precision forging machines are better equipment.
In summary, the forging process must strictly control the deformation temperature, deformation amount and deformation speed. Three factors, ignoring one of them-one will not get high-quality damage, but in fact the three are affected by many factors. It is very complicated to handle the relationship between the three comprehensively and a lot of work must be done.
