Treatment of melt for atomization technology

Abstract

An improved method of manufacturing a powder metal material by water, gas, plasma, or rotating disk atomization is provided. The method includes adding at least one additive to a melted metal material before or during the atomization process. The at least one additive forms a protective gas atmosphere surrounding the melted metal material which is at least three times greater than the volume of melt to be treated. The protective atmosphere prevents introduction or re-introduction of contaminants, such as sulfur (S) and oxygen (O2), into the material. The atomized particles produced include at least one of the following advantages: median circularity of at least 0.60, median roundness of at least 0.60, less internal pores, less internal oxides, and an increased sphericity of the microstructural phases and / or constituents.

Description

BACKGROUND OF THE INVENTION1. Field of the Invention[0001]This invention relates generally to powder metal materials, and methods of forming powder metal material by water or gas atomization or any other atomization process that requires the material to be atomized to go through the creation of a bath of liquid metal.2. Related Art[0002]Powder metal materials can be formed by various processes such as by water atomization, gas atomization, plasma atomization, or rotating disk. Common atomization processes include applying a fluid (water, gas, oil, or plasma) to a melted metal material to form a plurality of particles. During the water atomization process, the cooling rate of the melted metal is much faster than the cooling rate in gas atomization, which leads to the irregularly-shaped particles that are not generally desirable for metal injection molding, thermal spraying, additive manufacturing processes such as selective laser sintering, electron beam melting, three-dimensional pr...

AI Technical Summary

Benefits of technology

The invention provides a better way to make powder metal materials. It involves adding a protective gas to the melted metal to prevent impurities from entering. The melt is then atomized to create particles with a high degree of circularity and roundness, and less internal pores and oxides.

Problems solved by technology

However, gas atomization is three to nine times more expensive than water atomization.

Another common problem encountered in most atomized powders is the presence of internal porosities and internal oxides.

These defects will negatively impact the mechanical properties of the parts made from the powders.

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