PRODUCTION OF TI-6AL-4V ALLOY POWDERS BY PLASMA ROTATING ELECTRODE PROCESS

The experimental study of the production of Ti-6Al-4V powders by the rotating electrode process (PREP) was carried out in order to determine the optimum operating conditions to obtain the powders consisting of uniform particle size. The average particle size of the powders decreases by increasing the diameter of rotating electrodes (anodes made of Ti-6Al-4V), and their rotating speed. Under the condition of the anode diameter of 30 mm and the rotating velocity of 200 s-1, on average diameter of the powder particles of 270 μm with a minimum standard deviation of 10 μm was attained by controlling plasma gas flow, plasma current and melting rate of the anode to be 1.7 × 10-5 m-3&middots-1, 200 A and 1.5 approximately 3.0 × 10-7 m3&middots-1, respectively. In order to keep such a small standard deviation of the particle size of the powder, it was also important to maintain a homogeneous melting condition on the anode surface.