In the field of metal materials processing, titanium and titanium alloys are widely used in aerospace, medical, chemical and other fields due to their excellent physical and chemical properties. In order to meet the demand for titanium and titanium alloy rods, wires and profiles in different fields, in addition to the common forging production method, for such materials with a diameter of less than 100mm, the hole rolling method has also become an important production method. In this article, the hole rolling technology for titanium alloy rods, wires and profiles and its characteristics will be introduced in detail.
Hole rolling is a processing method that applies rolling force to the metal material through rotating rolls to make it undergo plastic deformation. In the hole rolling process of titanium alloy, the rolled parts (i.e., titanium alloy materials to be processed) are fed between the rotating rolls and gradually deformed under the squeezing action of the rolls until they reach the desired shape and size.
The hole rolling of titanium alloy bars, wires and profiles has the following significant features:
I. Uneven deformation
Due to the differences between the rolled parts and the shape of the hole pattern, the natural extension of the rolled parts at various points along the width direction will be inconsistent, resulting in uneven deformation. This uneven deformation may affect the mechanical properties and surface quality of the material, so the rolling process requires strict control of rolling parameters and hole design to ensure uniform deformation of the material.
Second, prone to overheating
Titanium's thermal conductivity is relatively low, which means that in the rolling process, the heat is not easy to dissipate from the deformation region. When the deformation rate is fast, the deformation of the intense parts are prone to overheating, which may lead to changes in the microstructure of the material, which in turn affects its mechanical properties and corrosion resistance. Therefore, appropriate cooling measures need to be taken in the rolling process to reduce the temperature of the material and prevent the occurrence of overheating.
Third, high productivity but complex tools
Hole rolling method has the advantage of high productivity, because it can be completed at once more than one rolling pass, thereby reducing the production cycle and cost. However, the rolling tool is relatively complex, requires precise design and manufacture to ensure the accuracy and stability of the hole pattern. In addition, for titanium alloy profiles with many specifications and small batch sizes, a large number of different sizes and shapes of holes are required. Replacement of the hole pattern also need to adjust and calibrate the mill, which is both labor-intensive and time-consuming, increasing production costs. Therefore, titanium alloy profiles are mostly not produced by the hole rolling method, but by other processing methods that are more suitable for small batch production.
Fourth, the transverse width and spread than steel
In the hole rolling process of titanium alloy, the transverse broadening (that is, the deformation of the rolled parts in the width direction) is larger than steel. This means that more attention needs to be paid to the deformation of the rolled parts in the width direction during the rolling process, in order to avoid the problem of excessive or insufficient width spread. At the same time, it is also necessary to fully consider this feature in the hole design to ensure that the rolled material has the required shape and size.
In summary, the hole rolling technology for titanium alloy bars, wires and profiles has the advantages of high production efficiency and wide application range, but there are also some challenges and limitations. In order to give full play to the advantages and overcome the limitations of the hole rolling technology, it is necessary to continuously optimize the rolling process and equipment design to improve the processing quality and production efficiency of the material.
