Twin-Drum Slab Thickness Estimation for Wedge Control
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Solution Overview
Problem
Existing methods for controlling wedges in twin-drum type continuous casting devices struggle to minimize meandering and plate passing troubles due to non-uniformities in casting drum rigidity and the distance of thickness distribution meters from the casting device, leading to delayed feedback and inaccurate wedge control.
Innovation Solution
A method that calculates estimated plate thicknesses at both ends of the slab using deformation characteristics of the casting drum housing and screw-down system, adjusts the screw-down position of the rolling mill to maintain a prescribed range of wedge ratios, and uses a control device to implement these adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a thickness distribution meter is installed close to the casting device for rapid feedback control, then the response time for wedge control is improved, but the risk of damage from molten metal increases
Solution Approach 1:
The patent introduces an intermediary measurement approach by using the casting drum's screw-down position and deformation characteristics as proxies for direct thickness measurement. Instead of placing a thickness distribution meter close to the casting device, the system calculates estimated plate thicknesses based on the relationship between screw-down position and actual thickness, thereby avoiding the need to install sensitive equipment in the hazardous zone while still achieving rapid feedback control
2Manufacturing precision
If the screw-down position of casting drums is adjusted to minimize wedges, then the uniformity of plate thickness is improved, but the complexity of control system increases
Solution Approach 1:
The patent applies preliminary action by pre-acquiring the deformation characteristics of the casting drum housing and screw-down system before actual slab casting. These characteristics are stored and used during production to calculate estimated plate thicknesses. This preprocessing approach simplifies the real-time control system, as it only needs to retrieve pre-acquired data and perform calculations based on current screw-down positions, rather than managing complex real-time measurement and adjustment systems
Solution Approach 2:
The patent creates a virtual model (copy) of the casting process by establishing the relationship between screw-down position and plate thickness through deformation characteristics. Instead of directly measuring and controlling physical thickness variations, the system uses this virtual model to estimate thickness based on screw-down position data, thereby simplifying the control system while maintaining manufacturing precision
3Manufacturing precision
If the rolling mill screw-down position is adjusted based on estimated thickness, then the wedge ratio control is improved, but the accuracy of thickness estimation must be maintained
Solution Approach 1:
The patent implements feedback control by continuously monitoring the screw-down position of the rolling mill and adjusting it based on calculated estimated plate thicknesses. The system calculates the difference between entry-side and exit-side wedge ratios and adjusts the screw-down position to minimize this difference. This closed-loop feedback mechanism ensures that wedge ratio control maintains high accuracy by continuously correcting based on real-time conditions while relying on the pre-acquired deformation characteristics for thickness estimation
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 effectively reduces meandering and plate passing troubles by minimizing differences in material speed and plate thickness across the rolling mill, ensuring precise control and reduced operational issues.
Implementation Method 1
cooling and solidifying the molten metal on the circumferential surfaces of the casting drums
Implementation Method 2
solidifying the molten metal on the circumferential surfaces of the casting drums
Implementation Method 3
The pair of casting drums press the slab with a prescribed pressing force
Implementation Method 4
roll the cast slab using a pair of work rolls
Data Source
AI summary
A slab manufacturing method in which casting drum housing screw-down system deformation characteristics which have been acquired prior to the start of slab casting and which indicate deformation characteristics of a housing configured to support a casting drum and deformation characteristics of a screw-down system configured to screw down the casting drum is used to calculate an estimated plate thickness at both end portions of a slab in a width direction thereof from Expression 1 ((estimated plate thickness on entry side of rolling mill)=(screw-down position of casting cylinder)+(elastic deformation of casting drum)+(casting drum housing screw-down system deformation)+(drum profile of casting drum)−(elastic deformation of casting drum at time of screw-down position zero-point adjustment)), an entry-side wedge ratio and an exit-side wedge ratio are calculated on the basis of the estimated plate thickness calculated from Expression 1.