Aluminum Hot Strip Rolling Layout for Precise Temperature-Time Control

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Solution Overview

Problem

Current aluminum hot strip rolling mills lack the ability to independently adjust and control the temperature-time path during the hot rolling process, limiting the material properties of the produced aluminum alloys and requiring additional processing steps, while also facing challenges with compact design and maintenance accessibility.

Innovation Solution

Incorporating an intermediate stand cooling system and a cooling section at the exit of the tandem finishing rolling train, along with a trimming shear and strip drying unit, to allow for precise control of cooling curves and temperature adjustments, enabling targeted temperature control and reduced production time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If compact tandem rolling mill design with short stand spacing is used, then installation space is reduced and productivity is improved, but maintenance accessibility of equipment deteriorates and strip centricity control becomes difficult

Engineering Contradiction:
Improveproduction outputVSAvoidmaintenance accessibility
Core Design Contradiction:
ProductivityVSEase of repair

Solution Approach 1:

The tandem rolling mill is divided into multiple independent stands (first stand, second stand, third stand, etc.) with distinct functions. Each stand can be independently maintained or adjusted without shutting down the entire line, as the continuous processing capability allows intermediate storage and re-threading of strips. This segmentation enables maintenance of individual components while preserving overall productivity.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If compact tandem rolling mill design with short stand spacing is used, then installation space is reduced, but strip centricity control deteriorates due to lateral drift

Engineering Contradiction:
Improveinstallation spaceVSAvoidstrip centricity control
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

Tension measuring rolls are installed between stands to continuously monitor strip tension and position. This feedback system detects lateral drift early and allows automatic adjustment of guiding mechanisms or rolling parameters to maintain centricity, even in compact configurations with short stand spacing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Transfer tables and guiding mechanisms act as intermediaries between stands, actively controlling strip position and orientation. These intermediary devices compensate for lateral drift by mechanically adjusting the strip path, ensuring centric alignment is maintained despite reduced stand spacing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If rolling speed is increased to achieve coiling temperature above 300°C in compact mills, then productivity is improved, but manufacturing precision of temperature-time path deteriorates

Engineering Contradiction:
Improverolling speedVSAvoidtemperature-time path control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The temperature control process is segmented into distinct zones: heating zone in the first stand, controlled cooling zone in intermediate stands, and final cooling zone before the coiler. Each zone has independent cooling capability, allowing precise control of the temperature-time path even at high rolling speeds by adjusting cooling in each segment independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically changes cooling parameters (water flow rate, spray intensity) in different stands based on real-time temperature measurements. This allows the temperature-time path to be precisely controlled by adjusting parameters in each zone independently, maintaining manufacturing precision despite high rolling speeds.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If cooling section is added to control strip temperature, then temperature-time path control is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature controlVSAvoidcooling system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The rolling stands serve multiple functions: they perform the primary rolling function and simultaneously serve as cooling zones through integrated water spray systems. This multi-functionality eliminates the need for separate dedicated cooling sections, reducing device complexity while maintaining precise temperature control capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cooling function is merged with the rolling stands by integrating water spray nozzles and cooling channels directly into the stand structures. This combination consolidates multiple functions into unified components, reducing the number of separate devices and simplifying the overall system while achieving precise temperature control.

Inventive Principle:
Principle #5Merging (Combining)

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 solution allows for improved microstructure control, increased production output, and the ability to produce aluminum alloys with enhanced mechanical properties without the need for additional cold rolling steps, while maintaining a compact mill design and preventing surface defects.

Implementation Method 1

the cooling of a few degrees Celsius caused by natural convection between the last stand and the coiler

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the cooling section...allows to cool down the aluminum hot strip to a coiling temperature

Methodology Applied
Scientific EffectConduction (thermal): Conduction (thermal)

Implementation Method 3

interstand cooling systems...arranged between the individual tandem rolling stands

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the temperature-dependent recrystallization and diffusion processes that occur during hot rolling of aluminum

Methodology Applied
Scientific EffectRecrystallization: Annealing

Implementation Method 5

the temperature-dependent recrystallization and diffusion processes that occur during hot rolling of aluminum

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3060358B2Aluminum hot strip rolling train and method for hot rolling an aluminum hot strip
Publication Date: 2024.04.17 SMS GROUP GMBH
  • EP3060358B2 patent drawingFigure 1
  • EP3060358B2 patent drawingFigure 2
  • EP3060358B2 patent drawingFigure 3

AI summary

The invention relates to an aluminum hot strip rolling train comprising a multi-stand tandem finish rolling train (2) with at least one winding reel (8) arranged downstream in the rolling direction and at least one paired cooling section (4). The aim of the invention is to provide a solution which allows cooling curves and temperature-time paths in the rolling stock to be adjusted in an improved manner during an aluminum hot strip rolling process in a tandem finish rolling train. This is achieved in that the at least one cooling section (4) is arranged in the discharge region of the aluminum hot strip rolling train, and the tandem finish rolling train (2) is paired with at least one trimmer (6) arranged downstream in the rolling direction.