Eq

However, there is a practical limit to the magnitude of the apex angle. Above about 50°, flow of molten metal from the base of the tundish is impaired because of welled-up water, and the incidence of metal freeze-up in the exit nozzle is also found to increase at higher apex angles, especially at higher pressures (Fig. 10). To decrease attenuation in water pressure, a short water-jet length is preferred, but again there are practical limits. It is normally found that using apex angle to control fineness leads to dangerously unstable conditions. It is far better to select a good stable setup with essentially zero rejection of melt and spray toward the jets and tundish and then provide the necessary pressure to achieve the desired particle size.

Water-art &&2Ü

ütrihzed ■ted

Semi-angln bolwaan water jabs.

Semi-angln bolwaan water jabs.

Jeting pressure (80 kjg.'cm2)

'/M y/f///////////////;

Impassible i (accompanied by yy^

Ä, vinKlüd-up water) ¿jl

Daubed f.|>ffiy IfliiVi

Good

Jar wbcity. rnJi isg

Jar wbcity. rnJi aaa

Fig. 10 Effect of jet angle on (a) mass median particle diameter and on (b) stability of water atomization at various water velocities. Source: Ref 1, 14

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