Forming Of Titanium Alloy Forgings

In the field of high-end manufacturing, titanium alloy forgings have become key materials for extreme working conditions such as aerospace, deep-sea exploration, and medical implantation due to their advantages of light weight, high strength, corrosion resistance and high temperature resistance. From aircraft landing gears and engine disks to ship components and artificial joints, their forming relies on precise control of force and heat, which is a precision manufacturing process that pursues ultimate performance under stringent constraints.

 

 

 

The forming of titanium alloy forgings starts with an accurate grasp of material properties. Titanium alloy is highly chemically reactive and tends to react with oxygen, nitrogen and hydrogen in air at high temperatures to form brittle and hard layers, leading to cracks. It has poor thermal conductivity, which easily causes uneven deformation during heating. It features high deformation resistance and a narrow plastic range; improper temperature will result in cracking or coarse grains, impairing mechanical properties. Besides, it has high viscosity and poor fluidity, and poor lubrication may cause die sticking and tearing.

 

Therefore, its forming is not simple forging, but a whole-process precise control. Only by fully understanding material properties can reasonable processes be formulated to ensure product quality.

 

 

The primary step in forming is material selection and pre-treatment. Titanium alloys are classified into α, β and α+β types, among which α+β titanium alloy is widely used for its excellent comprehensive performance. The composition of typical grades such as Ti-6Al-4V directly determines the properties of forgings.

 

Raw materials must be strictly controlled. Sponge titanium is proportionally mixed with alloying elements, then purified by multiple vacuum remelting to remove hydrogen and oxygen impurities, ensuring uniform composition and eliminating defects such as pores and porosity. The blank is further subjected to homogenization annealing to refine grains, laying a solid foundation for subsequent forging.

 

 

The key to forming lies in temperature and force control. The precise balance between heat and force is the core of titanium alloy forging. For the characteristics of titanium alloy, common forging processes are all based on the core principles of "precise temperature control and uniform stress":

 

Free forging: For large and simple parts, repeated upsetting and drawing refine grains and densify the structure.

Hot die forging: Die preheating preserves heat, suitable for complex parts with higher dimensional accuracy.

Isothermal forging: Constant high-temperature slow forming with low stress, mainly used for high-end precision components.

Advanced processes: Isothermal forging, multi-directional die forging and others enable near-net-shape forming and improve material utilization.

 

The forging temperature is generally controlled at 800–1100℃. Different grades require matched temperature ranges, and heating is carried out in vacuum or inert atmosphere to prevent oxidation and embrittlement. The heated blank must be quickly transferred and forged in time to avoid reduced plasticity caused by surface cooling. Special lubricants such as glass lubricants are used to reduce friction, prevent die sticking and tearing, and ensure forming quality.

 

 

The final step in forming is finishing and inspection. Titanium alloys after forging must undergo heat treatment, finishing and strict inspection to become qualified products.

 

Heat treatment including annealing, solution treatment and aging optimizes microstructure and properties, relieves residual stress, and improves strength, plasticity and corrosion resistance. Finishing processes such as grinding and polishing correct dimensional deviations, remove oxide layers and ensure precision and surface quality.

 

Quality inspection runs through the whole process as the last line of defense. Non-destructive testing such as ultrasonic testing and CT scanning detects internal defects. Mechanical property tests verify strength, elongation and other indicators-for example, the tensile strength of Ti-6Al-4V forgings is usually 800–1200MPa. All indicators must meet industrial standards to ensure stable batch consistency.

 

 

Ruihang Group mainly produces Titanium and Titanium Alloy products with the complete industry chain,including smelting,forging, straightening,rolling,surface treating,testing process.We are a technology and innovation enterprise that integrates R&D, production and sales into one integrated system.For any purchasing needs, feel free to contact us at email: Sam.Rui@bjrh-titanium.com.