What are the forging methods of titanium materials?
Forging is a method of forming a mechanical part, a workpiece, a tool or a blank by applying an external force to a titanium billet (excluding a sheet) to cause plastic deformation, change in size, shape, and performance. In addition, depending on the way the slider moves and the vertical and horizontal movement of the slider (for forging of the elongated part, lubrication cooling and part forging of high-speed production), the compensation device can increase the movement in other directions. Different methods are used, the required forging force, process, material utilization, production, dimensional tolerance and lubrication cooling method are different. These factors are also factors that affect the level of automation.
According to the movement mode of the blank, the forging can be divided into free forging, upsetting, extrusion, die forging, closed die forging, and closed upsetting. Closed die forging and closed upset forging have high material utilization due to the absence of flash. Finishing of complex forgings is possible with one or several processes. Since there is no flash, the area of force applied to the forging is reduced and the required load is also reduced. However, care should be taken not to completely limit the blank. To this end, the volume of the blank is strictly controlled, the relative position of the forging die is controlled, and the forging is measured to reduce the wear of the forging die.
According to the movement mode of the forging die, forging can be divided into pendulum, pendulum swivel, roll forging, cross wedge rolling, boring ring and cross rolling. Swing, swivel and shackle can also be used for precision forging. In order to improve the utilization of materials, roll forging and cross rolling can be used as a front-end process for slender materials. The same rotary forging as free forging is also partially formed, which has the advantage that it can be formed in the case of a smaller forging force than the forging size. This type of forging, including free forging, expands from the vicinity of the mold surface to the free surface during processing. Therefore, it is difficult to ensure accuracy. Therefore, the movement direction of the forging die and the swaging process can be controlled by computer. The forging force obtains products with complex shapes and high precision, such as forgings such as steam turbine blades with large variety and large size.
In order to achieve high accuracy, care should be taken to prevent overload at the bottom dead center, control speed and mold position. Because these will have an impact on forging tolerances, shape accuracy and forging die life. In addition, in order to maintain accuracy, you should also pay attention to adjust the slider rail clearance, ensure the stiffness, adjust the bottom dead center and use the auxiliary transmission and other measures.
Titanium forging materials are mainly pure titanium and titanium alloys of various compositions. The raw materials of the materials are bar stock, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of the metal before deformation to the cross-sectional area after deformation is called the forging ratio. Correct selection of forging ratio, reasonable heating temperature and holding time, reasonable initial forging temperature and final forging temperature, reasonable deformation amount and deformation speed have a great relationship to improve product quality and reduce cost. Generally, small and medium-sized forgings use round or square bars as blanks. The grain structure and mechanical properties of the bar are uniform and good, the shape and size are accurate, and the surface quality is good, which is convenient for mass production. As long as the heating temperature and deformation conditions are properly controlled, high-quality forgings can be forged without requiring large forging deformation.