Rolling Method for High Response Crown Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Rolling mills with decrease bending devices having lower response than increase bending devices face challenges in quickly changing settings during rolling, leading to instability and reduced product quality due to external factors like material thickness and temperature fluctuations.

Innovation Solution

Implementing a rolling method that utilizes high response increase bending devices to compensate for the slower response of decrease bending devices by adjusting the roll bending force at the start and end of rolling, and maintaining a composite force to achieve roll balance, even when using flexible and detachable hydraulic piping for decrease bending devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If flexible and detachable hydraulic piping is used for decrease bending devices to facilitate roll replacement, then ease of operation is improved, but response speed deteriorates due to pressure fluctuations being absorbed

Engineering Contradiction:
Improveroll replacementVSAvoidresponse speed
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The hydraulic system is segmented into two independent circuits: one for increase bending devices with fixed piping, and another for decrease bending devices with flexible piping. This segmentation allows each circuit to be optimized independently - the fixed piping circuit provides high response speed while the flexible piping circuit facilitates easy roll replacement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary control mechanism where the increase bending devices serve as the primary control means for crown/shape control, compensating for the slower response of decrease bending devices. This intermediary role allows the system to maintain high response control capability even when using flexible piping for decrease bending devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If decrease bending devices are built into backup roll chocks, then ease of manufacture is improved, but response speed deteriorates due to requirement for flexible piping

Engineering Contradiction:
Improvedevice installationVSAvoidresponse speed
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The hydraulic system is segmented into two independent circuits: one for increase bending devices with fixed piping, and another for decrease bending devices with flexible piping. This segmentation allows each circuit to be optimized independently - the fixed piping circuit provides high response speed while the flexible piping circuit facilitates easy roll replacement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary control mechanism where the increase bending devices serve as the primary control means for crown/shape control, compensating for the slower response of decrease bending devices. This intermediary role allows the system to maintain high response control capability even when using flexible piping for decrease bending devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If only high response increase bending devices are used for crown control, then response speed is improved, but reliability deteriorates due to inability to eliminate external factors like material thickness and temperature fluctuations

Engineering Contradiction:
Improveresponse speedVSAvoidcontrol stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent employs both increase and decrease bending devices working in opposition to each other, similar to counterweight principles. The increase bending devices provide high response control while the decrease bending devices provide additional stability, together compensating for external disturbances like material thickness and temperature fluctuations.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The control system uses a composite approach combining two types of bending devices with different characteristics - high response increase bending devices and stable decrease bending devices. This composite system leverages the strengths of both device types to achieve both high response speed and reliable control stability.

Inventive Principle:
Principle #40Composite materials

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 approach enables high response crown/shape control, improving product quality and yield by maintaining optimal roll bending force despite fluctuations, and reducing the need for frequent roll replacements and hydraulic piping adjustments.

Implementation Method 1

roll bending devices which can be changed in roll bending force during rolling by control of the hydraulic pressure

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2554284B1Rolling method of metal flat-rolled product
Publication Date: 2014.11.19 NIPPON STEEL & SUMITOMO METAL CORP
  • EP2554284B1 patent drawingFigure 1
  • EP2554284B1 patent drawingFigure 2
  • EP2554284B1 patent drawingFigure 3

AI summary

The present invention has as its task to be able to impart a high response crown/shape control function to a rolling mill with a response of decrease bending devices inferior to increase bending devices even under conditions causing a decrease roll bending force to act. To achieve this task, before the start of rolling, both the increase bending force and the decrease bending force are made to act and the composite force constituted by a roll bending force which corresponds to the roll balance force is made to act on a work roll chock. At the time of the start of rolling, the decrease bending force is held at a constant value while the increase bending force is made to change and a composite force constituted by a predetermined roll bending force (decrease bending force) is made to act on the work roll chock for rolling. At the time of the end of rolling, the increase bending force is returned to the state before the start of rolling and a composite force with the decrease bending force constituted by the roll bending force corresponding to the roll balance force is made to act on the work roll chock. In that state, the rolling is ended.