Continuous Casting Mold Flow Control for Impurity Mixing Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for controlling molten steel flow in continuous casting machines fail to accurately estimate and control the molten steel flow index, which is crucial for minimizing defects caused by impurities like bubbles and inclusions, leading to suboptimal casting quality.

Innovation Solution

A control method that estimates the molten steel flow state in real-time using operation conditions and temperature data, calculates a molten steel flow index indicating impurity mixing, and adjusts operation conditions such as casting speed, magnetic flux density, and nozzle submerging depth to maintain the flow index within appropriate ranges, ensuring optimal flow velocities and turbulence energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetic field is applied to molten steel in a mold to control the flow, then the quality of castings can be stabilized, but unexpected variation in operation makes it difficult to fully control the flow of the molten steel

Engineering Contradiction:
Improvequality stabilityVSAvoidflow control accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent employs feedback control by measuring the actual temperature distribution in the mold using embedded thermocouples and comparing it with the theoretically calculated temperature distribution. Based on the temperature difference, the system adjusts operating parameters (casting speed, meniscus level, magnetic field strength) to achieve the desired molten steel flow control, thereby overcoming operational variations and achieving precise flow control for high-quality castings

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the molten steel flow velocity at the solidification interface is increased to prevent bubbles and inclusions from being trapped, then defect occurrence is reduced, but the complexity of controlling multiple operation parameters increases

Engineering Contradiction:
Improvedefect occurrenceVSAvoidcontrol system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes multiple operating parameters (casting speed, meniscus level, magnetic field strength) in a coordinated manner based on the calculated temperature distribution. By adjusting these parameters together rather than individually, the system achieves precise control of molten steel flow velocity at the solidification interface, preventing bubble and inclusion entrapment while managing control complexity through integrated parameter adjustment

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If temperature measurement with embedded elements is used to control molten steel flow, then flow estimation accuracy is improved, but the ability to estimate molten steel flow index indicating impurity mixing is insufficient

Engineering Contradiction:
Improveflow estimation accuracyVSAvoidimpurity mixing information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent uses temperature distribution as an intermediary parameter to infer molten steel flow characteristics. By calculating the temperature distribution based on heat conduction equations and comparing it with actual measurements, the system derives information about molten steel flow velocity and patterns, which indirectly provides information about impurity mixing conditions without directly measuring them

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the production of high-quality castings by effectively controlling the molten steel flow index, reducing defects and improving casting quality by maintaining optimal flow velocities and turbulence energy levels.

Implementation Method 1

a technique controls a position of a discharge port and a discharge angle of the submerged entry nozzle relative to a position at which the moving magnetic field is applied, within appropriate ranges, when continuous casting is performed while a moving magnetic field is applied so that a braking force is applied to a discharge flow of molten steel

Methodology Applied
Scientific EffectElectromagnetic stirring: Electromagnetic Stirring

Implementation Method 2

molten steel poured through a submerged entry nozzle into a mold starts to be solidified from the mold wall surface side into a shell shape

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3928890B1Control method for continuous casting machine, control device for continuous casting machine, and manufacturing method for casting
Publication Date: 2023.12.27 JFE STEEL CORP
  • EP3928890B1 patent drawingFigure 1~2
  • EP3928890B1 patent drawingFigure 3
  • EP3928890B1 patent drawingFigure 4(a)~4(b)

AI summary

A control device 10 of a continuous casting machine according to one embodiment of the present invention includes: a molten steel flow state estimator 11 estimating, by on-line real-time system, a flow state of molten steel in a mold by using an operation condition of the continuous casting machine 1 and temperature data on the molten steel in the mold; a molten steel flow index calculator 12 calculating, by on-line real-time system, a molten steel flow index on the basis of the flow state of the molten steel estimated by the molten steel flow state estimator 11, the molten steel flow index being a factor of mixing of impurities into a casting inside the mold; and an operation condition controller 13 controlling the operation condition of the continuous casting machine 1 so that the molten steel flow index calculated by the molten steel flow index calculator 12 is within an appropriate range.