Casting Rolling Mass Flow Control via Speed Master Torque
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Solution Overview
Problem
Existing casting and rolling systems for endless strand materials face challenges in maintaining constant and uniform mass flow, particularly due to discrepancies in drive synchronization between the strand casting machine and the rolling line, leading to potential disruptions such as material accumulation or tearing, especially with thicker materials where traditional looping control is not effective.
Innovation Solution
A method where a pass sequence model sets a target rotational speed for the first rolling line and a target torque for the strand guide rollers, with the first roller frame acting as a 'speed master' to regulate mass flow, ensuring synchronization and constant mass flow across both systems by determining the rotational speed and torque distribution based on material thickness and processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional looping control is used to maintain mass flow, then mass flow stability is improved for thin materials, but it becomes ineffective for thicker materials where the strand material is too stiff to form loops
Solution Approach 1:
The patent changes the control parameter from rotational speed (traditional looping control) to torque for strand guide rollers. This parameter change allows the system to effectively control mass flow for thicker, stiffer materials that cannot form loops, while maintaining effectiveness for thinner materials as well.
Solution Approach 2:
Instead of using the strand material's flexibility to form loops for mass flow control, the patent inverts the approach by using torque control on the drives to directly regulate mass flow. This inversion makes the control method applicable to both flexible thin materials and stiff thick materials.
2Ease of operation
If individual drives are independently controlled in the rolling line, then operational flexibility is improved, but drive synchronization difficulties cause mass flow disruptions
Solution Approach 1:
The patent implements a superordinate drive controller that receives feedback from all individual drives and the pass sequence model, and adjusts torque distribution to maintain constant mass flow. This feedback mechanism ensures synchronization while preserving operational flexibility.
Solution Approach 2:
The superordinate drive controller serves multiple functions: it controls torque distribution across all drives, maintains mass flow constancy, coordinates the speed master roller frame, and adapts to different operating conditions. This multi-functionality resolves the contradiction between flexibility and synchronization.
3Device complexity
If rotational speed is controlled for all drives, then mass flow regulation is simplified, but the complexity of synchronization and detection systems increases
Solution Approach 1:
The patent segments the control approach by designating one roller frame as the 'speed master' whose rotational speed determines the mass flow, while all other drives are controlled by torque. This segmentation simplifies the overall control structure while maintaining synchronization.
Solution Approach 2:
Instead of controlling all drives by rotational speed (which would require complex synchronization), the patent inverts the approach by controlling most drives by torque and using one speed master. This inversion reduces detection requirements while maintaining reliability.
4Reliability
If torque is controlled for all roller frames, then mass flow constancy is improved, but the first roller frame loses its ability to dictate speed and mass flow
Solution Approach 1:
The patent segments the torque control application by excluding the first roller frame (speed master) from torque control and applying it only to subsequent roller frames and strand guide rollers. This segmentation preserves the speed master's ability to dictate mass flow while maintaining constancy through torque control elsewhere.
Solution Approach 2:
Different control strategies are applied to different parts of the system: the first roller frame uses rotational speed control to set the overall pace, while subsequent frames use torque control to maintain constant mass flow. This local differentiation optimizes both speed regulation and mass flow constancy.
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 ensures stable mass flow by allowing the first roller frame to dictate speed and mass flow, eliminating the need for rotational speed detection in other drives, and allows for automatic setting of mass flow constants in both the strand casting machine and rolling line, preventing disruptions and maintaining consistent material thickness and temperature control.
Implementation Method 1
The melt solidifies in the mold on the primary cooled walls of the chill-mold 111 in the chill-mold
Implementation Method 2
Heating is connected downstream of the roughing frames, preferably as an inductive heating 129, in order to heat the roughed strand material 200 to a desired finishing rolling temperature
Data Source
AI summary
A method for operating a casting/rolling system and to a corresponding system for casting and rolling an endless strand material. The casting/rolling system comprises a strand casting machine and a rolling train arranged downstream of the strand casting machine. The method has the following step: controlling the drive for the rollers of the first roller frame of the rolling train by means of a drive control in response to a target value specification of the pass sequence model. Furthermore, the drive of the at least one strand guiding roller is controlled by a strand guiding roller drive control in response to a target value specification of the strand casting machine drive model.