Abstract: TC4 titanium alloy powder was prepared by electrode induction melting gas atomization(EIGA). The atomization flow field was simulated， and the effects of extension length of the catheter on powder morphology， powder size distribution， hollow ball rate， apparent density and flow ability were investigated. The results showed that with the increase of extending length of the catheter， the negative pressure zone increases and the atomization powder is broken more fully.When the extending length is 3mm， negative pressure zone splits into two independent small zones， and the bulk powder and hollow spheres increase. When atomization pressure， the melting power and the extending length are 6.0MPa， 60kW and 2mm， respectively， the negative pressure area， which is large and inverted triangular， fills the lower part of the whole catheter while the atomization is more complete. The printable powder production rate is 51.60%. Apparent density is 2.870g/cm³， flow ability is 22.23s/50g and hollow ball rate is below 3%. TC4 powder prepared by EIGA is more suitable for laser direct deposition.

Key words: atomized powder, TC4 titanium alloy, annular nozzle, atomizing simulation;negative pressure zone, powder size distribution