Twin-Drum Slab Casting Control for Wedge Thickness Reduction
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Solution Overview
Problem
Existing slab casting methods face challenges in accurately controlling the wedge formation in slabs, leading to meandering issues during rolling, due to difficulties in maintaining parallelism of casting drums and inconsistent rigidity, which results in uneven sheet thickness and increased waste time in feedback control.
Innovation Solution
A twin-drum continuous casting method that calculates estimated sheet thicknesses on both ends using the casting drum housing screw down system deformation characteristics, allowing for precise control of screw down positions to minimize the difference in sheet thickness, thereby reducing wedge formation and meandering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a thickness distribution meter is installed close to the casting device to reduce wasted time, then feedback control accuracy is improved, but the meter may be damaged by falling molten metal
Solution Approach 1:
The patent uses a camera to capture images of the slab and creates a digital model (copy) of the thickness distribution, replacing the need for a physical thickness distribution meter near the casting device. This digital copy allows for safe and accurate measurement without exposing sensitive equipment to molten metal
Solution Approach 2:
The patent replaces the mechanical thickness distribution meter with an optical measurement system (camera and image processing). This substitution eliminates the need for physical contact with the hot slab and removes the risk of molten metal damage to the measurement device
2Stability of the object's composition
If the rotation axes of casting drums are maintained parallel, then casting stability is improved, but wedge formation occurs due to non-uniform reaction forces from the slab
Solution Approach 1:
The patent applies different crown amounts to different regions (left and right ends) of the casting drum. By making the drum surface non-uniform with location-specific adjustments, it compensates for the non-uniform reaction forces from the slab, maintaining parallel rotation axes while achieving uniform sheet thickness
Solution Approach 2:
The patent dynamically adjusts the crown amount and wedge amount parameters of the casting drum based on real-time measurement data. By changing these geometric parameters, the system compensates for thickness variations and maintains both drum parallelism and sheet uniformity
3Manufacturing precision
If crown and wedge of slab are controlled by adjusting casting drum positions, then sheet thickness is improved, but device complexity increases
Solution Approach 1:
The patent implements a closed-loop feedback system where a camera continuously measures the slab thickness distribution, and the control unit automatically adjusts the crown and wedge amounts based on this feedback. This automated feedback loop simplifies operation while maintaining high precision thickness control
Solution Approach 2:
The system uses the slab itself as the measurement target for the camera, eliminating the need for separate sensors or probes. The slab's own reflected light provides the measurement data, making the system self-sufficient and reducing additional complex components
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 more accurate reduction of wedge formation in slabs, reducing meandering issues during rolling and improving the efficiency of the casting process by minimizing waste time and ensuring consistent sheet thickness.
Implementation Method 1
molten metal is injected into a pool formed of the peripheral surfaces of the casting drums, and the molten metal is cooled to be solidified on the peripheral surfaces of the casting drums
Data Source
AI summary
A slab casting method using a twin-drum continuous casting device manufactures a slab by solidifying molten metal by a pair of rotating casting drums includes calculating estimated sheet thicknesses on both ends in a width direction of the slab from equation 1 ((estimated sheet thickness)=(cylinder screw down position)+(elastic deformation of casting drum)+(casting drum housing screw down system deformation)+(drum profile of casting drum)−(elastic deformation of casting drum at the time of screw down position zero adjustment)) by using a casting drum housing screw down system deformation characteristic indicating a deformation characteristic of housings that support the casting drums and a deformation characteristic of a screw down system that screws down the casting drums obtained before casting of the slab starts, and controlling screw down positions of cylinders provided on both ends in a width direction of the casting drums.