Reversible Rolling Mill with Intermediate Reeling for Strip Processing
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Solution Overview
Problem
Current combined pickling and rolling plants face limitations in productivity and investment costs, particularly with reversible rolling mills, which struggle to match the quality and performance of tandem rolling mills while controlling surface finish and handling large coils efficiently.
Innovation Solution
A combined pickling and reversible cold rolling plant design featuring a pickling line, increased storage capacity, and a reversible rolling mill with two stands, a first reel for winding after the first rolling step, and a second reel for winding in the opposite direction, with cutting and welding mechanisms to manage coil size and weight, allowing for continuous rolling and controlled surface finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a four- or five-stand tandem rolling mill is used, then productivity and surface quality are improved, but investment cost increases significantly
Solution Approach 1:
The patent divides the rolling process into two separate reversible rolling stands instead of using a single complex multi-stand tandem mill. Each stand performs specific rolling passes, with the strip being reeled between stands. This segmentation allows the system to achieve tandem mill productivity through continuous operation while using simpler, less expensive reversible rolling equipment.
Solution Approach 2:
The patent implements continuous rolling operation where the pickling line feeds continuously into the rolling mill, and the rolling mill operates without interruption by reeling the strip between passes. The storing means maintains continuous supply of pickled strip, and the welding means joins strip ends to eliminate interruptions, ensuring continuous useful action throughout the process.
2Device complexity
If reversible rolling mill is used, then investment cost is reduced, but surface finish control and productivity deteriorate
Solution Approach 1:
The rolling process is segmented into multiple passes across two separate reversible stands, with the strip being reeled between them. This allows optimization of each stand's function and enables surface finish control through careful sequencing of rolling passes, eliminating the need for complex tandem mill equipment while maintaining manufacturing precision.
Solution Approach 2:
The patent introduces reeling means as an intermediary between the two reversible rolling stands. This intermediary mechanism allows the strip to be temporarily stored and repositioned between passes, enabling precise control over the rolling sequence and surface finish development without requiring the strip to pass through multiple fixed tandem stands.
3Productivity
If jumbo coils weighing over 60 tons are used, then productivity approaches continuous mill values, but coil handling structure cost increases significantly
Solution Approach 1:
The patent changes the coil size parameters from industrial jumbo coils (60+ tons) to intermediate-sized coils (10-20 tons). This parameter change maintains high productivity by avoiding frequent coil changes while keeping coil weights within the capacity of standard handling structures, eliminating the need for expensive specialized infrastructure.
4Productivity
If increased storage capacity is provided, then continuous rolling is enabled, but plant complexity increases
Solution Approach 1:
The storing means serves multiple functions: it buffers the continuous pickling line output, supplies strip to the rolling mill, and enables uninterrupted operation during coil changes. This multi-functionality allows a single storage component to support continuous rolling without requiring separate complex systems for each function, thereby limiting the increase in overall plant complexity.
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 configuration enhances productivity and surface quality, achieving comparable performance to four- or five-stand tandem rolling mills with lower investment costs, enabling the production of coils with specific weights and sizes compatible with standard handling structures, and allowing for controlled surface finish required by automotive and household appliance industries.
Implementation Method 1
a welder, arranged between the storing means and the at least two first rolling stands, and adapted to weld a head of the rolled strip exiting the second rolling step, obtained from a cut performed by the first cutting means, with a strip head coming from the storing means
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
A pickling and rolling plant for pickling and rolling a metal strip, comprising a continuous pickling line; storing means (20, 20') for storing the pickled strip having a capacity of 1000-3000 metres of strip length; a reversible rolling mill having at least two first stands (19) downstream of said storing means (20); a first reel (21), downstream of said at least two first stands, for winding the strip after an odd rolling step, for winding a coil weighing from 100 to 300 tons and with a diameter of up to 6 metres; a welder (2'), arranged between the pickling line and the first stands; at least one second reel (16), upstream of the first stands and downstream of the welder (2'), for winding at least one portion of the strip after an even rolling step in the direction opposite to the odd step, said second reel being sized to wind strip portions with specific weight from 15 to 21 kg/mm; first cutting means (22, 23), arranged between said second reel and the first stands (19), which are adapted to cut the rolled strip each time a strip portion with specific weight from 15 to 21 kg/mm is wound onto the second reel; wherein said welder (2') is adapted to weld a head of the rolled strip cut by the first cutting means with a strip head still to be rolled.