Roll Casting Flatness Control for Thin Metal Strip
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Solution Overview
Problem
The production of thin hot-rolled steel strips using the two-roll casting process faces challenges in achieving standard flatness tolerances due to high production speeds, resulting in uneven temperature and stress profiles, which lead to internal stress conditions and unevenness in the cast strip, making it difficult to maintain desired mechanical properties and surface quality.
Innovation Solution
Implementing a flatness measurement system that uses real-time data to influence the metal strip's flatness during formation between the casting rolls or in-line thickness reduction, through closed-loop control of the roll nip, thermal influencing, and surface profile adjustments, ensuring uniform temperature and thickness profiles to achieve desired flatness values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high production speed is used in two-roll casting process, then productivity is improved, but manufacturing precision deteriorates due to uneven temperature and stress profiles
Solution Approach 1:
The patent implements a feedback control system that measures the actual flatness of the metal strip during production and uses this information to adjust process parameters in real-time. Sensors detect flatness deviations, and the control system modifies casting parameters to compensate, allowing high production speeds to be maintained while achieving standard flatness tolerances through continuous correction of temperature and stress profile variations
Solution Approach 2:
The patent systematically varies key process parameters including casting temperature, cooling rate, and roll speed to optimize both productivity and flatness. By changing these parameters dynamically based on material properties and production requirements, the process achieves high production speeds while maintaining manufacturing precision through controlled parameter adjustments that prevent excessive temperature and stress gradients
2Productivity
If high solidification rate is used to achieve thin strip cast thickness, then productivity is improved, but manufacturing precision deteriorates due to turbulent flow conditions and temperature fluctuations
Solution Approach 1:
The patent applies local quality control by implementing zone-specific cooling and temperature management in different regions of the casting process. Different sections of the mold and roll system receive customized thermal treatment to compensate for local variations in heat generation and material flow, ensuring uniform temperature distribution even at high solidification rates that enable thin strip production
Solution Approach 2:
The patent performs preliminary thermal conditioning and process preparation before the actual high-speed casting begins. Pre-heating sequences, preliminary cooling calibration, and advance parameter setting are implemented to establish stable thermal conditions that can sustain high solidification rates without developing problematic temperature fluctuations or turbulence during production
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 significantly reduces flatness deviations by up to 50%, achieving homogeneous mechanical properties, improved surface quality, and compliance with standard flatness values, even at low starting thicknesses, thereby enhancing the overall quality of the hot-rolled metal strip.
Implementation Method 1
metal melt solidifies continuously at the lateral surfaces of the rotating, internally cooled casting rolls
Implementation Method 2
a flatness measurement is performed on the moving metal strip, and the flatness measured values from this flatness measurement are used to influence the flatness of the metal strip
Data Source
AI summary
Processes for continuous production of a thin metal strip, in particular a steel hot strip, directly from a metal melt and with a strip cast thickness of <10 mm by the roll-casting process. The cast metal strip is fed for in-line thickness reduction, and then to a storage device. To achieve a high-quality, hot-rolled metal strip with flatness tolerances comparable to those which can currently be achieved in the production of hot-rolled metal strip from continuous-cast thin slabs or slabs, at cast thicknesses of between 40 and 300 mm, in a continuous production process starting directly from metal melt. With the low strip cast thickness, a flatness measurement is performed on the moving metal strip, and the measurement results of this flatness measurement are used to influence the flatness of the metal strip in a targeted way.