Crucible-Free Induction Melting and Atomization for Metal Powder
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Solution Overview
Problem
Existing methods for crucible-free melting and atomization of materials, such as those described in DE4102101A1 and EP1765536B1, result in large grain size distribution widths, making it difficult to achieve precise control over the grain size of metal powders, leading to increased manufacturing costs and inefficiencies.
Innovation Solution
A device and method involving an induction coil with tapered sections and an atomization nozzle where the atomization gas is introduced parallel to the melt flow, accelerating it to the speed of sound, and the melt flow is inductively heated before entering the nozzle, ensuring precise control over grain size and distribution by preventing cooling and freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the atomisation gas is introduced perpendicular to the melt flow direction through a lateral opening, then the melt flow is broken up into drops, but the grain size distribution width becomes large and manufacturing precision deteriorates
Solution Approach 1:
The patent changes the introduction direction of atomisation gas from perpendicular (lateral) to parallel with the melt flow direction. This dimensional change in flow configuration allows the gas to enter through the same opening as the melt, creating a co-flow arrangement that produces finer, more uniformly distributed powder grains while maintaining ease of manufacture
Solution Approach 2:
The patent merges the melt flow and atomisation gas flow into a single common passage, where both flows are introduced through the same opening and travel in the same direction. This combining of flows allows for better control over the atomisation process and results in narrower grain size distribution
2Device complexity
If the melt flow is cooled by the atomisation gas before entering the nozzle, then the atomisation process is simplified, but the powder quality deteriorates due to grain size fluctuations
Solution Approach 1:
The patent applies preliminary heating action to the melt flow by introducing it into a heating zone before the atomisation nozzle. This pre-heating prevents the melt from cooling and solidifying prematurely, ensuring it maintains liquid state and consistent temperature entering the nozzle, which is critical for producing uniform powder grains
Solution Approach 2:
The patent changes the temperature parameter of the melt flow by introducing it into a heating zone where it is heated to a controlled temperature range. This parameter change ensures the melt is at the optimal temperature for atomisation, preventing premature cooling and enabling precise control over the resulting grain size distribution
3Ease of manufacture
If a crucible is used for melting, then the melting process is simple, but chemical reactions with the crucible coating contaminate the material
Solution Approach 1:
The patent extracts and eliminates the crucible from the melting process by using direct inductive heating of the material rod. This removal of the crucible eliminates the source of chemical contamination while maintaining the simplicity of the melting process through contactless electromagnetic heating
Solution Approach 2:
The patent replaces the mechanical crucible containment system with an electromagnetic field-based inductive heating system. The induction coil generates an electromagnetic field that directly heats the material rod without requiring physical contact or containment, thereby eliminating chemical reactions between the material and crucible coating
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
This approach allows for the production of metal powders with a narrow grain size distribution, enabling precise setting of desired grain sizes and reducing wastage, thus lowering manufacturing costs and improving the quality of the powder produced.
Implementation Method 1
The induction coil is configured to melt the material of the material rod for producing a melt flow
Implementation Method 2
the atomisation gas which is to be introduced and/or is introduced into the atomisation nozzle through the first opening is accelerated in a direction parallel to the flow direction of the melt flow, preferably parallel to a flow direction of the melt flow through the atomisation nozzle, at least up to the speed of sound of the atomisation gas
Data Source
AI summary
The present disclosure relates to a device for melting a material without a crucible and for atomizing the melted material in order to produce powder, comprising: an atomizing nozzle; an induction coil having windings, which become narrower in the direction of the atomizing nozzle at least in some sections; and a material bar at least partially inserted into the induction coil. The induction coil is designed to melt the material of the material bar in order to produce a melt flow. The induction coil and the atomizing nozzle are arranged in such a way that the melt flow is or can be introduced into the atomizing nozzle through a first opening of the atomizing nozzle in order to atomize the melt flow by means of an atomizing gas, which can be introduced into the atomizing nozzle.