As a star product in the field of high-end industrial materials, the titanium alloy tube melting and forging process occupies an important position in cutting-edge fields such as aerospace, marine engineering, and biomedicine due to its high specific strength, strong corrosion resistance, and excellent thermal stability. Its unique material advantages are not only reflected in the mechanical properties of tensile strength of more than 900MPa, but also in the biocompatibility that perfectly matches the human skeleton. These characteristics make the processing technology of titanium alloy tubes a technological commanding height in modern manufacturing.
Precision Melting: Genetic Coding of Material Properties
1. Raw Material Purification Process
Using the dual process of plasma cold bed melting (PAM) and electron beam melting (EBM), the purity of sponge titanium and alloy elements such as Al and V is increased to 99.995% through high-temperature refining above 3000℃. The depth of the molten pool is precisely controlled in the range of 500-800mm to ensure that the impurity elements are fully volatilized.
2. Tube forming technology
Direct casting method: Prepare Φ300×6000mm tubular ingots through the centrifugal casting process, and the wall thickness tolerance is controlled within ±1.5mm
Drilling method: Deep hole drilling of Φ500mm solid ingots, using the gun drilling process to achieve deep hole processing with an L/D ratio of 30:1, and processing accuracy of H7 level
Intelligent forging: directional regulation of microstructure
1. Multi-directional die forging process
In the temperature window of 20-50℃ below the β phase transformation point (the specific temperature is adjusted according to the alloy grade), a 20,000-ton fast forging machine is used to implement three-way forging. The deformation of each pass is strictly controlled in the range of 30%-50%, and the metal streamline distribution is simulated in real time through DEFORM software.
2. Radial forging finishing
The four-hammer radial forging machine forges at a frequency of 120 times/minute
The core rod adopts gradient cooling technology, and the surface hardness is maintained at 62 - 65HRC
The wall thickness reduction rate of each pass is 8%-12%, and the final forging temperature deviation is ≤±15℃
Process control: digital practice of quality assurance
1. Online detection system
The composite detection unit integrating a laser diameter gauge (accuracy 0.01mm) + an infrared thermal imager (±2℃) + ultrasonic flaw detection (sensitivity Φ0.8mm) realizes 100% online full inspection.
2. Organization optimization strategy
The optimal heat treatment system is determined through Thermo-Calc thermodynamic calculation, and a double annealing process is adopted: the first 850℃×2h/AC, the second 600℃×4h/AC, so that the grain size is stabilized at the ASTM 8-10 level.
This manufacturing system, which integrates advanced technologies such as material calculation, intelligent equipment, and digital twins, not only increases the yield rate of titanium alloy tubes to more than 85%, but also increases the fatigue life of products by 3-5 times compared with traditional processes. With the introduction of additive manufacturing technologies such as 3D printing, titanium alloy tube melting and forging process are continuing to evolve in the direction of topological optimization structures and gradient functional materials.
