Casting Slab Cooling and Reduction for Center Looseness
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Solution Overview
Problem
Current continuous casting methods face challenges in addressing internal defects like looseness and cracks in casting slabs, particularly at the center and corners, due to uneven cooling and deformation during the solidification process, which are difficult to resolve with existing high-deformation-rate and low-deformation-rate reduction methods.
Innovation Solution
A slab cooling and reduction method involving sequential corner electromagnetic induction heating and surface cooling in the continuous casting machine to create a temperature difference, allowing controlled reduction deformation that transfers deformation from the surface to the center, thereby reducing looseness and preventing corner cracks, while maintaining surface quality through cyclic phase transformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-deformation-rate heavy reduction method is used to solve center looseness, then center looseness is improved, but corner cracks occur due to large deformation at low temperature
Solution Approach 1:
The patent applies different temperature conditions to different regions of the casting slab: the corner region is heated to high temperature (above solidification point) while the center region maintains lower temperature. This local quality differentiation allows the corner to have high plasticity and resist cracking during reduction, while the center region undergoes effective deformation to eliminate looseness.
Solution Approach 2:
The corner electromagnetic induction heating device performs preliminary heating of the corner region before the reduction process. By pre-heating the corner to high temperature, the material gains sufficient plasticity to withstand the large deformation forces during reduction without cracking, while the center region remains at appropriate temperature for loosness elimination.
2Stability of the object's composition
If reduction is performed at point location with single roll, then center looseness is addressed, but reduction distance is short limiting effectiveness
Solution Approach 1:
The patent transitions from single-point reduction to distributed line reduction by arranging multiple reduction rolls (first and second reduction rolls) along the length of the casting slab. This dimensional extension allows deformation to be applied over a longer distance, improving the effectiveness of looseness elimination while maintaining control over the deformation process.
3Stability of the object's composition
If multiple segments perform reduction over long distance, then segregation is improved, but deformation rate is low limiting looseness improvement
Solution Approach 1:
The patent employs a dynamic reduction system where the first and second reduction rolls can be independently controlled to provide varying deformation rates along the length of the casting slab. This dynamic approach allows high deformation rate at critical locations (center region) for looseness elimination, while maintaining appropriate deformation for segregation control, optimizing both effects simultaneously.
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 method effectively improves the internal and surface quality of casting slabs by transferring deformation to the center, reducing looseness and cracks, and enhancing the compactness and plasticity of the slab, with a reduction in porosity by one third compared to conventional processes.
Implementation Method 1
a corner electromagnetic induction heating device and a reduction device are sequentially arranged at an exit of a continuous casting machine
Implementation Method 2
The corner of the casting slab is inductively heated to increase the corner temperature
Implementation Method 3
the surface of the casting slab is cooled at a cooling rate of 0.1-12℃/s in a horizontal section of the casting machine
Implementation Method 4
a certain amount of reduction is carried out on the casting slab, so that internal quality is improved by pressing and merging the looseness of the center
Data Source
Figure 1~2B
AI summary
Provided is a slab cooling and reduction method for improving the quality of a casting slab. In the method, cooling water is used at the horizontal section of the casting machine to control the surface temperature of a casting slab (1), so as to increase the temperature difference between the inside and the outside of the casting slab, and then the casting slab undergoes reduction at an exit of a casting machine, so as to realize the effective transfer of reduction deformation to the center of the casting slab, thereby ameliorating looseness at the center of the casting slab. In order to prevent the formation of corner cracks at a corner of the casting slab at a low temperature during the reduction process, a heating device is provided at the position of the corner of the casting slab after exiting the casting machine so as to increase the temperature of the corner of the casting slab. The method helps to improve both the surface quality and the internal quality of products.