Melt Supply Control for Strip Casting Systems

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Solution Overview

Problem

Conventional strip casting systems face challenges in controlling the supply of molten metal to the casting gap, leading to non-uniform product properties, surface defects, and safety issues due to uncontrolled oxidation and gravity-fed flow, which results in impurities and reduced productivity.

Innovation Solution

The implementation of an active means to transport molten metal from the casting furnace to the casting gap, using pressurization or pumping to control the volume flow and prevent oxidation, allowing for precise regulation and safety enhancements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an open trough system with gravity-fed flow is used to supply molten metal to the casting gap, then the system is simple in structure, but the control of melt supply is difficult and not dynamic, leading to non-uniform product properties

Engineering Contradiction:
Improvecontrol of melt supplyVSAvoidstructure of supply system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the gravity-fed mechanical system with an electromagnetic drive system that uses magnetic fields to actively transport and control the molten metal flow. This allows dynamic control of melt supply while maintaining structural simplicity through the use of field-based actuation rather than complex mechanical components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a fluid-driven mechanism where pressurized gas or liquid is used to control the flow of molten metal through the casting gap. This hydraulic/pneumatic approach enables precise control of melt supply dynamics while keeping the overall system structure relatively simple.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If a tundish is used to calm the molten metal, then the level of melt pool can be regulated, but the molten metal is prone to oxidation and forms oxide layers that degrade quality

Engineering Contradiction:
Improvequality of metal stripVSAvoidoxidation of molten metal
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an inert or reducing atmosphere into the casting zone to prevent oxidation of the molten metal. By controlling the gas environment with inert gases or reducing conditions, the harmful oxidation reactions are suppressed, improving metal strip quality without requiring a tundish.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent removes the tundish component from the system entirely, replacing its functions with direct electromagnetic control of melt flow and inert atmosphere protection. This extraction eliminates the oxidation problem associated with tundish exposure while maintaining reliable melt supply control.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the molten metal is fed by gravity through a tundish, then the system is simple to operate, but in the event of system failure, molten metal continues to flow towards the casting gap causing safety problems

Engineering Contradiction:
Improveoperation of supply systemVSAvoidsafety of casting process
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a dynamic control system using electromagnetic fields that can rapidly adjust and stop molten metal flow in response to system failures or abnormal conditions. This dynamic actuation provides safety control that gravity-fed systems cannot achieve, while the automated control maintains ease of operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback control mechanisms that monitor the casting process continuously and automatically adjust the electromagnetic drive or pneumatic/hydraulic system to stop melt flow when failures are detected. This feedback loop ensures safety while maintaining simple automated operation.

Inventive Principle:
Principle #23Feedback

4Productivity

If conventional gravity-fed feeding is used, then the equipment is simple, but the volume flow of molten metal cannot be controlled dynamically, reducing productivity

Engineering Contradiction:
Improvecasting speedVSAvoidcontrol system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces gravity-based passive flow with an electromagnetic drive system that enables dynamic control of molten metal volume flow. This allows casting speed to be increased and optimized without being limited by gravity-fed constraints, achieving high productivity with relatively simple field-based control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses pressurized gas or liquid systems to dynamically control the volume flow of molten metal to the casting gap. This pneumatic/hydraulic approach enables rapid adjustment of flow rates to optimize casting speed and productivity while maintaining manageable system complexity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 enables precise control of the molten metal supply, reducing impurities, improving product quality, and enhancing safety by preventing uncontrolled oxidation and flow, thus increasing productivity and ensuring consistent strip quality.

Implementation Method 1

at least one electromagnetic drive for transporting the molten metal from the casting furnace to the casting gap

Methodology Applied
Scientific EffectElectromagnetic drive: Electromagnetic Propulsion

Implementation Method 2

at least one pressurization for controlling the volume flow of the molten metal

Methodology Applied
Scientific EffectPressurization: Pressurisation

Implementation Method 3

the cast strip is formed, is delimited on at least one long side by a barrier that is continuously moved and cooled during the casting process

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3993921B1Melt supply for strip casting systems
Publication Date: 2024.04.10 SPEIRA GMBH
  • EP3993921B1 patent drawingFigure 1
  • EP3993921B1 patent drawingFigure 2
  • EP3993921B1 patent drawingFigure 3

AI summary

The invention relates to a strip casting system (1) for aluminum and/or aluminum alloys, comprising at least one casting furnace (3) and at least one rotational mold (2, 22, 23) which comprises a casting gap (21), wherein the at least one rotational mold (2, 22, 23) is designed as a roller pair (22, 23), shaper pair, caterpillar track pair, or belt pair, and the strip casting system (1) has at least one active means (4) for transporting molten metal (5) from the casting furnace (3) to the casting gap (21). The strip casting system (1) has a casting region (6) arranged upstream of the casting gap (21), said casting region (6) being delimited by the rotational mold (2, 22, 23) on at least one side, and the casting region (6) is designed such that a molten metal pool (52) is formed in the casting region (6), molten metal (5) flowing or being drawn from said pool into the casting gap (21). The casting furnace (3) is connected to the casting region (6) by a pipe system (41, 43), and the strip casting system (1) comprises means (46) for supplying the molten metal (5) into the casting region (6), said means being capable of supplying the molten metal (5) to the casting region (6) below the surface of the molten metal pool (52) formed in the casting region (6).