Water Atomization of Molten Metal for Magnetic Powder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing water-atomized metal powder struggle to achieve a high Fe-group element concentration, amorphous proportion, apparent density, circularity, and particle size, particularly for applications in high-frequency motors and reactors, while also being cost-effective and productive.
Innovation Solution
A water atomization process using flat spray nozzles with a specific arrangement and spray pressure, where cooling water is sprayed at a pressure of 10 MPa or more with a spread angle of 5° to 30° from multiple discharge ports, forming a convergence angle of 5° to 10° with the molten metal stream, and a water/molten steel ratio of 50 or more, to produce metal powder with an average particle diameter of less than 50 μm, an apparent density of 3.5 g/cm3 or more, and a circularity of 0.90 or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Fe-group element concentration is increased to achieve higher magnetic flux density, then the magnetic performance is improved, but the amorphous proportion and apparent density tend to decrease
Solution Approach 1:
The patent applies parameter changes by precisely controlling the convergence angle (5°-10°) and spread angle (5°-30°) of cooling water spray, along with maintaining water/molten steel ratio of 50 or more. These parameter adjustments enable the formation of amorphous structure even in high Fe-group element concentration alloys (76.0 at % or more), resolving the contradiction between magnetic flux density and amorphous proportion
Solution Approach 2:
The patent utilizes the periodic cooling action of water spray impinging on the molten metal stream at specific angles. This periodic thermal shock promotes rapid cooling and amorphization while maintaining high Fe-group element concentration, thereby achieving both high magnetic flux density and high amorphous proportion
2Speed
If the particle size is reduced to less than 50 μm for higher frequency applications, then the frequency performance is improved, but the apparent density and circularity become difficult to maintain
Solution Approach 1:
The patent changes the physical parameters of water spray including pressure (10 MPa or more), spread angle (5°-30°), and convergence angle (5°-10°) to achieve optimal atomization. This produces fine particles (D50 < 50 μm) with high apparent density (3.5 g/cm³ or more) and circularity (0.90 or more), simultaneously satisfying frequency response requirements while maintaining density
Solution Approach 2:
The patent employs hydraulic principles by using high-pressure water spray (10 MPa or more) with specific angular parameters to atomize the molten metal stream. The hydraulic impact and cooling action produce fine spherical particles with controlled size distribution and high apparent density, resolving the contradiction between particle size reduction and density maintenance
3Productivity
If water atomization is used to achieve high productivity and low cost, then the production efficiency is improved, but the apparent density and circularity of particles are insufficient
Solution Approach 1:
The patent optimizes water atomization parameters including convergence angle (5°-10°), spread angle (5°-30°), and water pressure (10 MPa or more) to transform conventional water atomization into a high-precision process. These parameter changes enable production of particles with apparent density of 3.5 g/cm³ or more and circularity of 0.90 or more, maintaining high productivity while achieving superior particle quality
Solution Approach 2:
The patent introduces dynamic control of water spray parameters during the atomization process. By adjusting the convergence angle and spray pressure dynamically, the process achieves optimal particle formation with high apparent density and circularity, resolving the contradiction between productivity and manufacturing precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively produces metal powder with a high Fe, Ni, and Co content of 76.0 at % or more, achieving an amorphous proportion of 90% or more, which is suitable for low loss and high magnetic flux density, and can be further enhanced with appropriate heat treatment.
Implementation Method 1
a method for producing water-atomized metal powder by dividing a molten metal stream, which is falling in a vertical direction, by spraying cooling water that impinges on the molten metal stream
Implementation Method 2
spraying cooling water that impinges on the molten metal stream... achieving an amorphous proportion of 90% or more
Implementation Method 3
spraying cooling water at a spray pressure of 10 MPa or more... dividing a molten metal stream by spraying cooling water
Data Source
AI summary
A method for producing water-atomized metal powder by dividing a molten metal stream, which is falling in a vertical direction, by spraying cooling water that impinges on the molten metal stream includes a step of spraying the cooling water at a spray pressure of 10 MPa or more and a spread angle in a range of 5° to 30° from each of three or more cooling water discharge ports arranged remote from the falling molten metal stream. The droplet diameter of the cooling water: 100 μm or less, the convergence angle: 5° to 10°, and the water/molten steel ratio: 50 or more.