Tantalum has high melting point and high density. It has good plasticity in annealing and stable performance at high temperature. The annealed tantalum material is soft and tough, which causes serious adhesion when cutting, and causes the tool to bond and wear. Especially when the cutting speed is lower than 20m/min, the phenomenon of sticking knife and tearing is more serious. When the cutting speed is higher than 40m/min, the tearing phenomenon is greatly reduced. The cutting tool should be as sharp as possible and the cutting speed should not be too low. Generally use cemented carbide as tool material, commonly used YG8, YW2, etc. Using larger rake Angle and the Angle, cutting tool geometry parameter is: gamma 35 ~ 45 O, O O = alpha = 5 ~ 8 O, O O Κ r = 90 O, Κ 'r = 5 O, gamma O1 = - 2 O ~ 2 O, gamma = 0.1 ~ 0.3 mm, b r epsilon = 0.2 ~ 0.5 mm, behind the front surface roughness Ra < 0.16 ~ 0.32 mu m, in order to reduce the friction and sticking phenomenon.
The selection of cutting parameters is as follows: rough turning c=30 ~ 70m/min, ap=5 ~ 8mm, f=0.2 ~ 0.4mm/r; When finishing or semi-finishing, c=50 ~ 80m/min, ap≤1.5mm, f=0.1 ~ 0.3mm/r. When cutting should use both cooling and lubrication cutting fluid, the flow should be sufficient.
Tantalum niobium smelting, processing technology innovation, such as: wet smelting - pulp extraction; Pyrolytic decomposition - low acid extraction; Offline analysis -- online analysis and microcomputer monitoring; Cold crystallization of potassium tantalate; Continuous jet precipitation production of low fluoride Ta2O5, Nb2O5 process; High purity Ta2O5 and Nb2O5 were produced by peroxidation precipitation.
