A gas atomizing nozzle for preparing metal powder

Abstract

A gas atomizing nozzle for preparing metal powder. In the invention, a chamber (4) is provided between the upper end cover (2) and the lower end cover (3), and at least one The inlet pipe (1) is set at the exit of the chamber as a Laval nozzle structure. This invention can effectively ensure that the high-pressure gas can reach the supersonic effect after passing through the annular throat of the Laval nozzle, and reduce the energy loss of the gas to the greatest extent. , the present invention also provides a gas drainage groove (5) on the upper end cover and a larger chamber on the upper end cover, which effectively avoids the clogging phenomenon of the nozzle during the working process.

Description

【Technical field】 [0001] The invention relates to the technical field of powder metallurgy, and relates to a nozzle used for gas atomization to prepare metal powder, in particular to a gas atomization nozzle which uses high-speed airflow to break metal melt into fine droplets and solidify into powder. 【Background technique】 [0002] At present, powder materials generally use fine powder or ultrafine powder as raw materials, so that sintered or processed materials with more uniform structure and better performance can be obtained. [0003] It is known that gas atomization technology is a commonly used production method for metal powder. The principle is that the molten metal enters the gas atomization zone after flowing out of the draft tube or the graphite nozzle, and is impacted and broken into fine droplets by the action of the high-speed airflow. Then the molten droplets solidify into powder particles under the action of surface tension and cooling of atomizing gas. Dur...

AI Technical Summary

Problems solved by technology

[0005] Chinese patent, the publication number is CN102837001A, and the publication date is December 26, 2012, disclosing "a fine metal powder atomization nozzle that is easy to flow out of the metal liquid ", the annular seam of this nozzle has no convergent section, which does not conform to the basic characteristics of "convergence-expansion" of the Laval nozzle, so the air velocity cannot reach supersonic speed, and it is impossible to have a good atomization efficiency

And the gas chamber is too small compared with the annular seam, it is difficult to stabilize the air pressure in the chamber

Therefore, when the air flow is ejected from the annular gap, there may be turbulent flow or air flow deflection, and there is a risk of nozzle clogging

[0006] Chinese patent, Publication No. CN102489711A, published on June 13, 2012, discloses "a gas atomizing nozzle for preparing fine metal powder", which has the typical "convergence- However, it is similar to a fine metal powder atomization nozzle in which liquid metal flows out easily. The gas temporary storage chamber is too small, and the airflow ejected from the annular gap may be turbulent. risk of clogging

[0007] Chinese patent, the publication number is CN103273070A, and the publication date is September 04, 2013, which discloses "an adjustable titanium and titanium alloy melt ultra-fine mist Although the annular seam of this nozzle also has the characteristics of "convergence-expansion", its throat curve is not smooth, that is, its first derivative is discontinuous, and the airflow energy will be greatly lost in the throat, which will weaken the airflow export speed

Secondly, similar to a gas atomizing nozzle for preparing fine metal powder and a fine metal powder atomizing nozzle for the easy outflow of metal liquid, the gas temporary storage chamber also has the problem of being too small

[0008] To sum up, the nozzles described in each patent have no structure to prevent metal droplets from clogging and solidifying, and the gas temporary storage chambers are too small, making it difficult to Forming a stable high-pressure chamber will cause a large loss of high-pressure gas energy and reduce the atomization efficiency; there will also be unstable air flow, which will easily cause nozzle blockage, etc.

Images