Casting Roll Crown Control Using Insulated Expansion Rings
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Solution Overview
Problem
Existing twin roll casting systems face challenges in reliably and effectively controlling the shape of the crown of the casting surfaces, which affects the cross-sectional thickness profile of the cast strip, due to thermal deformation and heat transfer issues with expansion rings.
Innovation Solution
The use of expansion rings with an insulating coating, positioned near the edge and center portions of the casting rolls, which can be heated and expanded to control the crown shape by varying their radial dimension, allowing for precise control of the casting roll crown and strip thickness through sensors and a control system that adjusts the speed of rotation and heating input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If expansion rings are positioned directly on the cylindrical tube to control crown shape, then the responsiveness to heat should improve, but the heat transfer from expansion rings to the tube causes the rings to be ineffective in expanding the tube
Solution Approach 1:
A thin annular member is introduced as an intermediary between the expansion ring and the cylindrical tube. This member acts as a heat barrier that prevents heat transfer from the expansion ring to the tube, allowing the expansion ring to effectively expand the tube without being compromised by heat loss.
Solution Approach 2:
The system is segmented into distinct components: the expansion ring, the thin annular member, and the cylindrical tube. This segmentation allows each component to perform its specific function independently, with the thin annular member specifically tasked with blocking heat transfer while allowing mechanical expansion to propagate.
2Adaptability or versatility
If the cylindrical tube thickness is reduced to increase responsiveness to expansion rings, then the control effectiveness should improve, but the tube becomes more susceptible to thermal deformation
Solution Approach 1:
The thin annular member serves as a thermal barrier that protects the cylindrical tube from excessive heat exposure. This allows the tube to maintain its structural integrity and resistance to thermal deformation while still being responsive to the mechanical expansion forces applied by the expansion rings.
3Device complexity
If conventional expansion rings are used without insulating coating, then the structure is simpler, but the heat transfer prevents effective crown control
Solution Approach 1:
The system uses a composite structure consisting of the expansion ring and the thin annular member with different thermal properties. The annular member is specifically designed with low thermal conductivity to block heat transfer, creating a composite system that achieves both structural simplicity and precise crown shape control.
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 enables precise control over the crown shape of the casting surfaces, resulting in a consistent and desired thickness profile of the cast strip, minimizing thermal fatigue and improving the responsiveness of the casting rolls.
Implementation Method 1
Each expansion ring has an insulating coating spaced from edge portions of the cast strip formed during the casting campaign
Implementation Method 2
The at least two expansion rings with insulating coating spaced within 450 mm of edge portions of the cast strip formed during the casting campaign may be heated and expanded to control the crown shape by varying their radial dimension
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A method and apparatus of continuously casting thin strip by controlling roll crown is provided. The apparatus for continuously casting thin strip by controlling roll crown includes at least two expansion rings positioned within and adjacent a cylindrical tube and spaced within 450 mm of edge portions of the cast strip formed on opposite end portions of casting rolls during a casting campaign. Alternatively or in addition, the apparatus includes at least one expansion ring within the cylindrical tube at a position corresponding to center portions of the cast strip formed on the casting rolls during a casting campaign. Each expansion ring has at least one heating element and an insulating coating thereon and is adapted to increase in radial dimension causing the cylindrical tube to expand changing roll crown of the casting surfaces of the casting rolls and thickness profile of the cast strip during casting.