Forging is a crucial forming method used to manufacture mechanical parts, workpieces, tools, or blanks by applying external forces to titanium metal billets (excluding plates). This process causes plastic deformation, altering the size and shape of the material while enhancing its performance.
Movement Modes in Forging
The movement of the slider during forging can be vertical or horizontal, which plays a significant role in various applications, including lubrication, cooling of slender parts, and high-speed production. Compensation devices can further enhance movement in other directions. These methods vary in terms of the required forging force, process, material utilization, output, dimensional tolerance, and lubrication and cooling techniques, all of which impact the level of automation.
Types of Forging
Depending on the movement of the billet, forging can be categorized into several types:
- Free Forging
- Upsetting
- Extrusion
- Die Forging
- Closed Die Forging
- Closed Upsetting
Among these, closed die forging and closed upset forging are notable for their high material utilization due to the absence of burrs. These methods enable precision machining of complex forgings with minimal processes, reducing stress areas and the required load.
Process Control and Material Management
It’s essential to control the volume of the billet, the relative position of the forging die, and the measurements of the forgings to minimize die wear. The movement modes of the forging die can include:
- Swing Forging
- Swing Rotary Forging
- Roll Forging
- Cross Wedge Rolling
- Ring Rolling
- Oblique Rolling
Rotary forging and ring forging can also achieve precision through controlled processes. To enhance material utilization, roll forging and cross rolling can serve as preliminary processes for slender materials.
Achieving High Precision
Rotary forging allows for local formation with smaller forging forces compared to the size of the final product. By controlling the movement direction of the forging die through computers, manufacturers can achieve complex shapes and high precision in products, such as steam turbine blades, with reduced forging forces.
Maintaining high accuracy requires careful attention to prevent overload at the bottom dead center, as well as controlling speed and mold position. These factors directly influence tolerance, shape accuracy, and die life.
Material Selection and Forging Ratio
The primary materials for titanium forging include pure titanium and various titanium alloys. The original forms of titanium materials are bars, ingots, metal powders, and liquid metals. The ratio of the cross-sectional area before deformation to that after deformation is referred to as the forging ratio.
Selecting the appropriate forging ratio, heating temperature, insulation time, and deformation parameters is vital for improving product quality and reducing costs. Typically, small and medium-sized forgings utilize round or square bars as billets due to their uniform grain structure, mechanical properties, and good surface quality, facilitating mass production.
With careful control of heating temperatures and deformation conditions, high-performance forgings can be achieved without significant deformation.