Endless Strip Rolling With Mega-Coil Accumulation for Thin Gauge Steel
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Solution Overview
Problem
Current combined continuous casting and metal strip hot-rolling plants face limitations in producing high-quality, thin hot-rolled products due to mechanical property constraints, requiring separate hot and cold rolling lines, long processing times, and difficulties in handling thin strips, which restrict the replacement of cold-rolled products with hot-rolled ones.
Innovation Solution
A combined continuous casting and metal strip endless rolling plant with a continuous casting line, multiple rolling mills, high-capacity reels for mega coil winding, and a reversible rolling mill to produce thin strips efficiently, allowing for continuous hot-rolling and reducing processing time by eliminating the need for separate cold-rolling lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot-rolling is performed immediately after continuous casting to reduce processing time, then productivity is improved, but the mechanical properties and surface quality of low-carbon steel products deteriorate
Solution Approach 1:
The rolling process is divided into multiple stands (roughing mill with 4 stands, finishing mill with 7 stands, third rolling mill with 4 stands) to progressively reduce thickness while controlling deformation. This segmentation allows hot-rolling to achieve thin gauge products while maintaining mechanical properties through controlled incremental reduction rather than single-pass rolling.
Solution Approach 2:
The patent changes the rolling temperature parameters and deformation parameters throughout the rolling process. By controlling the slab temperature, rolling speed, and reduction ratio at each stand, the process achieves both high productivity (continuous hot-rolling) and good mechanical properties (controlled microstructure development).
2Strength
If separate cold-rolling lines are used to achieve high-quality products, then mechanical properties and surface quality are improved, but device complexity and production time increase
Solution Approach 1:
The patent merges the hot-rolling and cold-rolling operations into a single continuous rolling line. The third rolling mill performs cold-rolling operations immediately after hot-rolling, eliminating the need for separate cold-rolling lines and warehouses. This integration maintains mechanical properties while reducing device complexity and production time.
Solution Approach 2:
The rolling line is designed to perform multiple functions: hot-rolling, cold-rolling, and coil winding in a single continuous process. This multi-functional line can produce both hot-rolled and cold-rolled products without requiring separate dedicated lines, thereby reducing overall plant complexity.
3Productivity
If thin strips are produced by hot-rolling to replace cold-rolled products, then productivity is improved, but handling difficulties and jamming risks increase
Solution Approach 1:
The patent introduces an intermediary accumulation system with large-diameter reels (minimum 1.5 meters) between the third rolling mill and the coil winding line. These reels act as intermediaries to buffer and manage thin strip material, preventing jamming during handling and allowing continuous production without interruption.
Solution Approach 2:
The patent changes the spatial arrangement by placing accumulation reels in a separate dimension (off-line accumulation area) rather than in the direct rolling path. This allows thin strips to be accumulated and managed without interfering with the continuous rolling process, solving the handling difficulty while maintaining productivity.
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
Enables the production of thinner strips with improved mechanical properties, reduces processing time, and increases production flexibility, allowing for the replacement of cold-rolled products with hot-rolled ones, while minimizing jamming risks and enhancing product quality.
Implementation Method 1
a continuous casting line for casting a slab
Implementation Method 2
a first rolling mill for roughing the slab and for obtaining a transfer bar; a second rolling mill for finishing the transfer bar and for obtaining a strip; a third rolling mill, comprising at least two first rolling stands, for further reducing the thickness of the strip
Implementation Method 3
accumulation means of the strip, downstream of said third rolling mill, comprising at least one first high-capacity reel, sized to wind and unwind a coil weighing from 80 to 250 metric tons and/or up to 6 meters in diameter
Data Source
AI summary
A combined continuous casting and endless rolling plant for a metal strip, comprising—a continuous casting line (1) for casting a slab;—a first rolling mill (6) for roughing the slab and for obtaining a transfer bar;—a second rolling mill (11) for finishing the transfer bar and for obtaining a strip;—a third rolling mill (18), comprising at least two first rolling stands (17), for further reducing the thickness of the strip;—accumulation means (20) of the strip, downstream of said third rolling mill (18), comprising at least one first high-capacity reel (37, 37′) dimensioned to wind and unwind a coil weighing from 80 to 250 tons and/or up to 6 meters in diameter, named mega coil;—flying cutting means (13), arranged between said third rolling mill (18) and said accumulation means (20), configured to cut the strip after the mega roll has been wound on the at least one first reel (37, 37′);—a cutting and winding line (22), downstream of said accumulation means (20), for cutting the strip of the mega coil and winding portions of said strip of the mega coil to a predetermined weight limit or coil diameter limit, producing a plurality of coils; wherein said cutting and winding line (22) is provided with a reversible rolling mill for performing at least one rolling of the strip before producing said plurality of coils.