Reconfigurable Hot Rolling Stand for Thin High-Strength Strip
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Solution Overview
Problem
Hot rolling mills face challenges in achieving small final thicknesses for high-strength materials due to limitations in work roll diameter, which affects torque transmission and roll neck safety, and existing solutions like multi-roll stands are not feasible for hot rolling due to space and cooling constraints.
Innovation Solution
The last rolling stand in a hot rolling train is converted between a four-high and a six-high configuration between rolling operations, allowing for optimized productivity and torque transmission by adjusting the configuration based on material strength, with further roll stands remaining as four-high stands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If work roll diameter is decreased to achieve smaller final thicknesses, then the final thickness is reduced, but the torque transmission capability deteriorates
Solution Approach 1:
The rolling stand is segmented into multiple roll layers (work rolls, intermediate rolls, backup rolls) arranged in a six-high configuration. This segmentation allows the system to achieve the rolling function with smaller work rolls while the intermediate and backup rolls provide the necessary structural support and torque transmission capability.
Solution Approach 2:
The solution transitions from a two-dimensional four-high roll arrangement to a three-dimensional six-high roll arrangement by adding intermediate rolls between the work rolls and backup rolls. This dimensional change enables better distribution of mechanical loads and improved torque transmission while maintaining small work roll diameters.
2Manufacturing precision
If work roll diameter is decreased to achieve smaller final thicknesses, then the final thickness is reduced, but the risk of roll neck fracture increases
Solution Approach 1:
The rolling stand is segmented into multiple roll layers (work rolls, intermediate rolls, backup rolls) arranged in a six-high configuration. This segmentation allows the system to achieve the rolling function with smaller work rolls while the intermediate and backup rolls provide the necessary structural support and torque transmission capability.
Solution Approach 2:
The solution transitions from a two-dimensional four-high roll arrangement to a three-dimensional six-high roll arrangement by adding intermediate rolls between the work rolls and backup rolls. This dimensional change enables better distribution of mechanical loads and improved torque transmission while maintaining small work roll diameters.
3Force
If multi-roll stands (12-high or 20-high) are used to solve torque transmission, then torque transmission is improved, but the space requirement and cooling capability deteriorate
Solution Approach 1:
Instead of uniformly increasing the number of rolls throughout the entire stand, the solution applies the six-high configuration locally at specific rolling stands where high-strength material processing is required. This allows optimized torque transmission only where needed while maintaining simpler four-high configurations elsewhere.
Solution Approach 2:
The six-high stand configuration serves multiple functions: it provides adequate torque transmission for high-strength materials, maintains compact space requirements compared to 12-high or 20-high stands, and allows sufficient cooling space for the work rolls. The same configuration can be applied to different rolling stands depending on material requirements.
4Adaptability or versatility
If the last rolling stand is converted between four-high and six-high configurations, then adaptability to different materials is improved, but the conversion complexity increases
Solution Approach 1:
The rolling stand configuration is made dynamic and changeable between four-high and six-high modes. The stand can be converted by adjusting the position of intermediate rolls and modifying the support structure, allowing adaptation to different material requirements while maintaining operational flexibility.
Solution Approach 2:
The same rolling stand structure is designed to perform multiple functions by supporting both four-high and six-high configurations. This universal design allows the stand to handle both soft materials (four-high mode) and high-strength materials (six-high mode) without requiring separate dedicated stands.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A hot rolling line has at least one first and one last roll stand (1a, 1d). A first and a second metal strip (2, 5) are rolled one after the other in the hot rolling line. Portions of the metal strips (2, 5) each pass first through the first, and only afterwards through the last, roll stand (1a, 1d) of the hot rolling line. The last roll stand (1d) is retooled between rolling of the first metal strip (2) and rolling of the second metal strip (5) from a four-high roll stand to a six-high roll stand or vice versa so that the last roll stand (1d) is configured for rolling the first metal strip (2) as a four-high roll stand with work rolls (3) and backup rolls (4) and for rolling the second metal strip (5) as a six-high roll stand with work rolls (6), intermediate rolls (7) and backup rolls (4).