High-energy gas atomizing nozzle for preparing metal and alloy powder

Abstract

The invention relates to a high-energy gas atomizing nozzle for preparing metal and alloy powder. The conventional atomizing nozzle generates unsteady supersonic gas flow, and is easy to have turbulence phenomenon to cause self-consumption loss of the energy of the supersonic gas flow. The high-energy gas atomizing nozzle comprises an intake pipe, a guide pipe, an upper end cover and a lower end cover, wherein a gas cavity encircled around the guide pipe is formed between the upper end cover and the lower end cover, inner sidewalls of the upper end cover and the lower end cover form an Laval spray pipe structure near the bottom end of the guide pipe, the Laval spray pipe structure comprises a contraction section, a throat and an expansion section, the high-energy gas atomizing nozzle is characterized in that the gas cavity is a symmetrical streamline structure, and the lower sidewall of the guide pipe is tangential to the outer wall of an outlet of the expansion section. According to the invention, through the Laval contraction-expansion type spray pipe in the symmetrical structure, the turbulence between the accelerated airflow can be reduced, the steady high-energy supersonic gas stream is generated, the efficient atomizing rate of the metal and the alloy thereof can be realized, and superfine powder of lower than 500 meshes reaches more than 65% in the prepared metal powder.

Description

technical field [0001] The invention relates to a device for producing superfine powder by atomizing molten metal with high-energy gas, in particular to a high-energy gas atomizing nozzle for preparing metal and alloy powder. Background technique [0002] Gas atomization to prepare metal and alloy powders has low harmful gas content and good powder sphericity, and is currently one of the most common powder preparation methods. The free-falling molten metal is usually atomized using unrestricted gas atomizing nozzles. The nozzle structure of this atomization method is simple, easy to control, and the liquid metal leak is not easy to block, so the production cost is low, but the average particle size of the obtained powder is relatively coarse, and the proportion of fine powder is low, generally distributed in the range of 60-300μm. In order to improve the gas atomization efficiency, a restrictive structure atomization nozzle was later developed, which shortened the gas fligh...

AI Technical Summary

Problems solved by technology

For example, the shrinking and expanding nozzle with the non-streamline transition structure of the gas cavity will lose a certain amount of energy when the gas flow flows in the gas cavity, and it also leads to the lack of sufficient acceleration area for the shrinking tube in front of the throat of the shrinking and expanding nozzle. Accelerate the high-pressure gas to the speed of sound, so a higher inlet pressure is required to achieve a supersonic flow from the nozzle of the contracting and expanding nozzle

Otherwise, the air flow will still flow at subsonic speed after passing through the throat of the shrinking and expanding nozzle, and it is difficult to reach supersonic speed

In addition, the contraction-expansion nozzle in the above-mentioned patent has an asymmetric structure, not a Laval contraction-expansion nozzle in the strict sense. Energy self-consumption loss

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