Endless Hot-Rolling Plant With Mega-Coil Strip Accumulation
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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 cold-rolling for low-carbon steels, and struggle with handling and processing thin strips, leading to increased production time and limited product mix.
Innovation Solution
A combined continuous casting and metal strip endless rolling plant with a continuous casting line, multiple rolling mills, and high-capacity accumulation means for forming mega coils, allowing for continuous hot-rolling and further thickness reduction, thereby overcoming jamming issues and enabling production of thinner strips with improved mechanical properties.
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, and thin-slab rolling mill with 4 stands), allowing progressive reduction of the slab while maintaining control over mechanical properties. This segmentation enables hot-rolling to produce strips with thicknesses down to 0.6-0.8mm while achieving acceptable mechanical properties through controlled deformation at each stage.
Solution Approach 2:
The patent changes the rolling parameters including temperature control, rolling speed, and reduction ratio at each stand to optimize both productivity and mechanical properties. By adjusting these parameters throughout the rolling process, the plant achieves a balance between fast processing and product quality.
2Manufacturing precision
If cold-rolling is performed after hot-rolling to improve surface quality and mechanical properties, then product quality is improved, but productivity deteriorates due to extended processing time and warehouse storage requirements
Solution Approach 1:
The hot-rolling process is designed to perform preliminary actions that traditionally required cold-rolling, including surface quality improvement and mechanical property enhancement. By achieving acceptable surface quality and mechanical properties directly through optimized hot-rolling, the need for subsequent cold-rolling and warehouse storage is eliminated, thereby maintaining high productivity.
3Productivity
If thin strips thinner than 0.6-0.8mm are produced by hot-rolling to increase productivity, then productivity is improved, but reliability deteriorates due to high risk of jamming during handling
Solution Approach 1:
The patent applies local quality by providing specific support and guidance mechanisms at critical locations where thin strips are most vulnerable to jamming. This includes specialized guiding devices, support rollers, and tension control systems positioned throughout the rolling and handling process to ensure reliable processing of ultra-thin strips.
Solution Approach 2:
Intermediary devices such as guiding mechanisms, support rollers, and tension control systems are introduced between the rolling stands and winding/reeling equipment to prevent direct contact and potential jamming of thin strips. These intermediaries protect the strips during handling while maintaining process continuity.
4Productivity
If the plant is configured for endless rolling to improve productivity, then productivity is improved, but adaptability deteriorates in handling different product specifications
Solution Approach 1:
The plant is designed with dynamic capabilities that allow it to switch between endless rolling mode and coil-to-coil mode depending on product requirements. The rolling mill stands, guiding devices, and winding/reeling systems can be dynamically adjusted and reconfigured to handle different product specifications, thicknesses, and production volumes, thereby maintaining both high productivity and adaptability.
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
The solution enables the production of thinner hot-rolled strips with mechanical properties comparable to cold-rolled products, reducing processing time and increasing production flexibility, allowing for the creation of high-quality DQ, DDQ, and EDDQ products, and expanding the range of Advanced High Strength Steels that can be produced.
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 rolling stands, for further reducing the thickness of the strip
Implementation Method 3
accumulation means of the strip comprising at least one first reel dimensioned to wind and unwind a coil weighing from 80 to 250 metric tons and/or up to 6 meters in diameter, named mega coil
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 rolling stands (17), for further reducing the N thickness of the strip; —accumulation means (20) of the strip comprising at least one first reel (37, 37′) dimensioned to wind and unwind a coil weighing from 80 to 250 metric tons and/or up to 6 meters in diameter, named mega coil; —first cutting means (13), arranged between said third rolling mill (18) and said accumulation means (20), configured to cut the strip after the mega coil has been wound on the at least one first reel (37, 37′); —at least one second reel (48) for winding portions of strip, unwound from said accumulation means (20), up to a predetermined weight limit or coil diameter limit; —second cutting means (47), arranged between said accumulation means (20) and said at least one second reel (48), adapted to cut the strip whenever a portion of strip wound on the at least one second reel (48) reaches said predetermined weight limit or coil diameter limit.