Tantalum has a high melting point, and its recrystallization annealing temperature is correspondingly high. The traditional vacuum annealing furnace is limited by materials and has a low temperature limit. For the recrystallization annealing of tantalum metal with a high melting point, it is difficult to achieve the purpose of recrystallization annealing even if the holding time is excessively extended. Using the traditional vacuum annealing method, the tensile strength of the annealed tantalum tube is 210MPa, the yield strength is 140MPa, and the elongation is 25%.
In order to further explain the invention, the following combined with the attached drawings and embodiments to describe the preferred example mode of the invention, the purpose, characteristics and advantages of the invention can be clearly seen.
According to the attached drawing, the steps of the invention are as follows:
1. Cleaning: The outer diameter 20mm, wall thickness 1mm, length 800mm tantalum tube (Ta1) cleaning, dry. Ensure that the inner and outer walls of tantalum tube are free of oil and water marks.
2. Feeding: First put the bulk tantalum tubes after cleaning into the heat-resistant material sleeve, and then send them into the vacuum annealing furnace along the axis through the automatic transmission device, and the automatic transmission device stops working.
3. Vacuum vacuuming: Start the mechanical pump first, when the vacuum degree is 103Pa, start the Roots pump, pump the vacuum degree is 1Pa, start the diffusion pump, pump the vacuum degree is 10-2Pa. The three-stage vacuum system ensures a high vacuum environment inside.
4. Annealing in induction furnace:
Start the automatic transmission device, the heat resistant sleeve equipped with tantalum tube passes through the induction coil of the induction annealing furnace at a speed of 20cm/min, and the temperature rises to 1500℃ higher than the recrystallization temperature of the tube within 3-5 seconds; The tube passes continuously through an induction coil.
5. Rapid cooling in vacuum induction annealing furnace: After the heat resistant sleeve equipped with tantalum tube is removed from the induction coil, the temperature is still very high. In order to fully inhibit the grain growth, the tantalum tube part from the induction coil is forced to enter the cooling water jacket for cooling. After cooling to 400℃, it is cooled to room temperature with the furnace: then it is baked.
