Analysis of the depth influence of rolling temperature on the microstructure and properties of titanium forgings
In the process of titanium alloy forging, the original microstructure characteristics of the blank, including its chemical composition, impurity distribution, selection of heat processing process parameters and subsequent heat treatment process, will have a profound impact on the microstructure and mechanical properties of the final forging.
First of all, when it comes to the selection of rolling temperature, this is a crucial link. When the rolling temperature specification is properly selected and ensures that the billet achieves a large deformation rate during the forging process, the adverse effects of the original structure can be effectively ruled out. However, in a real-world industrial production environment, achieving such a high deformation rate is not an easy task. With the reduction of the deformation rate, the adverse effects of the original structure gradually become prominent, which poses a potential threat to the quality of the forging.
Rolling temperature and microstructure of titanium alloys
The rolling temperature directly affects the microstructure of titanium alloys. Rolling at a suitable temperature can refine the grain of titanium alloys, thereby improving their strength. Excessively high rolling temperatures can lead to coarse grains, reducing the strength and toughness of the material. Conversely, too low a temperature can lead to excessive residual stresses during the rolling process, which also affects the final properties of the titanium alloy.
Taking titanium and titanium alloy ingots as examples, their original structure often shows coarse grains and low process plasticity. In order to improve this situation, the heating process before forging is particularly important. The strategy of heating the ingot above the phase change point and completing the main deformation process in the β zone proved to be effective. In the β zone, the deformation resistance of the material is significantly reduced, and the plasticity is greatly increased, which allows the as-cast structure to be broken more fully, thus increasing production efficiency and reducing energy consumption.
Further research and practice have proved that when the total deformation of the ingot reaches 70%~80%, the internal structure of the forging will change significantly. The originally coarse grains are refined to form a uniform and fine fibrous structure. This transformation of the microstructure not only improves the tensile strength of the material, but also significantly improves its plasticity index, making the forging more tough and durable when subjected to external force.
In addition, the selection of rolling temperature also needs to consider the specific composition and impurities of the material. Different titanium alloy compositions and impurity content have different effects on the selection of rolling temperature and the microstructure evolution during the forging process. Therefore, in actual operation, it is necessary to formulate reasonable rolling temperature specifications and forging process parameters according to the specific titanium alloy material to ensure that the quality and performance of the forgings reach the best state.
In summary, the rolling temperature has a profound impact on the structure and properties of titanium forgings. Rolling temperature is an important factor affecting the strength of titanium alloys. By reasonably controlling the rolling temperature, the microstructure of the titanium alloy, the original structure of the blank, phase transformation, work hardening and residual stress can be optimized, so as to improve the overall strength of the material. In the actual production process, it is necessary to formulate reasonable forging process parameters and heat treatment process according to the specific titanium alloy type and required performance, and carefully select the appropriate rolling temperature to further improve the mechanical properties and service life of forgings.
