The main materials used for forging titanium rods are pure titanium and titanium alloys with various compositions. The original states of the materials include titanium rods, ingots, metal powders, and liquid metals. The ratio of the cross-sectional area of a metal before deformation to the cross-sectional area after deformation is called the forging ratio. The correct selection of forging ratio, reasonable heating temperature and holding time, reasonable initial and final forging temperature, reasonable deformation amount and deformation speed are closely related to improving product quality and reducing costs. Generally, circular or square bar materials are used as blanks for small and medium-sized forgings. The grain structure and mechanical properties of the bar material are uniform and good, with accurate shape and size, good surface quality, and easy to organize for mass production. As long as the heating temperature and deformation conditions are reasonably controlled, high-quality forgings can be forged without significant forging deformation. On airplanes, titanium alloys are mainly used to manufacture the main load-bearing components such as beams, landing gears, hubs, and joints; Titanium alloy is mainly used in engines to manufacture force and heat parts such as adapter rings, impeller fans, compressor discs, and blades.

Titanium alloys are highly sensitive to forging process parameters, and changes in forging temperature, deformation amount, deformation, and cooling rate can cause changes in the microstructure and properties of titanium alloys. In order to better control the microstructure and properties of forgings, advanced forging technologies such as hot die forging and isothermal forging have been widely used in the forging production of titanium alloys in recent years. By using conventional forging techniques, titanium alloys can generally achieve equiaxed structure in forged components, resulting in high room temperature formability and strength. This provides a feasible method for solving the forming of large and complex titanium rod precision forgings. This method has been widely used in the production of titanium rods. One effective method to improve the fluidity of titanium rods and reduce deformation resistance Z is to increase the preheating temperature of the mold. Isothermal forging and hot die forging have been developed domestically and internationally in the past two to three decades.

How to improve the yield of titanium rod production, which can be achieved by using closed die forging method to forge titanium rod. Closed die forging must strictly limit the volume of the original blank, which complicates the material preparation process. Whether to adopt closed die forging should be considered from two aspects: profit and process feasibility. Subsequently, only heat treatment and cutting were performed on the Z-shaped blank. The forging temperature and degree of deformation are the fundamental factors determining the microstructure and properties of alloys. The heat treatment of titanium rods is different from that of steel, and forging is usually used to manufacture products with shapes and sizes close to scrap. It does not play a decisive role in the microstructure of the alloy. Therefore, the process specifications for the Z-step of titanium rods play a particularly important role. It is necessary to ensure that the overall deformation of the blank is not less than 30% and the deformation temperature does not exceed the phase transition temperature. In order to achieve high strength and plasticity of the titanium rod at the same time, the temperature and deformation degree should be distributed as evenly as possible throughout the entire deformed blank.

After recrystallization heat treatment, the uniformity of titanium rod and properties is inferior to that of steel forgings. The region of intense metal flow is characterized by fuzzy crystals at low magnifications and equiaxed fine crystals at high magnifications; Difficult to deform zone, due to small or no deformation, its structure often preserves the state before deformation. Therefore, in forging some important titanium rod parts (such as compressor discs, blades, etc.), in addition to controlling the deformation temperature below TB and the appropriate deformation level, it is very important to control the microstructure of the original blank. Otherwise, coarse grain structure or certain defects will be inherited into the forging, and subsequent heat treatment cannot eliminate them, resulting in the scrapping of the forging.

When forging titanium rod forgings with complex shapes on a hammer in a rapidly deformed area where thermal effects are locally concentrated. Even if the heating temperature is strictly controlled, the temperature of the metal may still exceed the TB of the alloy. For example, when forging a titanium rod blank with an I-shaped cross-section, if the hammer is too heavy, the temperature in the middle (web plate area) will be about 100 ℃ higher than that in the edge area due to the effect of deformation heat. In addition, the hard to deform zone and the zone with critical deformation level are prone to forming coarse-grained structures with relatively low plasticity and durability strength during the heating process after forging. So the mechanical properties of forgings with complex shapes forged on hammers are often very unstable. But it will lead to a sharp increase in deformation resistance, and reducing the forging heating temperature can eliminate the risk of local overheating of the blank. Increasing tool wear and power consumption requires the use of higher power equipment. During open die forging, the burr loss accounts for 15% -20% of the weight of the blank. The process waste in the clamping part (if this part must be retained according to the forging conditions) accounts for 10% of the weight of the blank. The relative loss of burr metal usually increases with the decrease of the blank weight. For some forgings with asymmetric structures, large cross-sectional area differences, and difficult to fill local areas, the burr consumption can reach up to 50%. Although closed die forging has no burr loss, the billet making process is complex and requires the addition of many transition tool grooves, which undoubtedly increases auxiliary costs.