Rolling Mill Wedge Control Using Load-Based Roll Gap Adjustment

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Solution Overview

Problem

Existing methods struggle to accurately control strip wedge in rolling processes due to the need for temperature measurement and the influence of mill constant differences, which complicates the calculation of strip thickness and wedge correction.

Innovation Solution

A rolling equipment and method that uses load sensors to measure strip load distribution and calculate post-rolling strip wedge without temperature measurement, adjusting hydraulic cylinders to control strip wedge through a strip wedge controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If temperature measurement is used to separate differential load due to strip wedge from temperature difference, then strip wedge control accuracy is improved, but device complexity increases and measurement precision becomes dependent on temperature measurement accuracy

Engineering Contradiction:
Improvestrip wedge control accuracyVSAvoidapparatus complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts only the necessary load measurement data from the rolling process, separating the differential load component caused by strip wedge from the overall rolling load. By using load sensors to directly measure the differential load between work side and drive side, the system eliminates the need for temperature measurement apparatus while still achieving accurate strip wedge control through computational separation of load components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the thermal measurement system (temperature sensors and measurement apparatus) with a mechanical load measurement system. By substituting temperature-based differential load separation with direct mechanical load sensing and computational analysis, the system achieves the same control objective with simpler hardware and improved reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If mill constant difference between work side and drive side is not considered, then calculation simplicity is maintained, but strip thickness calculation accuracy deteriorates

Engineering Contradiction:
Improvecalculation simplicityVSAvoidstrip thickness calculation accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention applies different mill constant values for the work side and drive side, recognizing that each side of the rolling mill has distinct mechanical characteristics. By assigning local quality parameters (different mill constants) to each side based on their specific load sensor measurements and mechanical properties, the system achieves accurate strip thickness calculation that accounts for asymmetries in the rolling mill structure and behavior.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If strip thickness is calculated only at middle portion, then measurement process is simplified, but wedge calculation capability is lost

Engineering Contradiction:
Improvecalculation process simplicityVSAvoidwedge calculation capability
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention segments the strip thickness measurement into multiple locations - specifically calculating thickness at both the work side and drive side in addition to the middle portion. This segmentation is enabled by the differential load sensor arrangement that provides independent load measurements from each side, allowing the system to compute multiple thickness values and derive wedge information without complicating the overall measurement process.

Inventive Principle:
Principle #1Segmentation

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 precise control of strip wedge in a simple structure by calculating the necessary working roll gap difference based on load measurements, independent of strip wedge or temperature disturbances.

Implementation Method 1

a drive side load sensor detecting the rolling reduction force due to the drive side hydraulic cylinder, a work side load sensor detecting the rolling reduction force due to the work side hydraulic cylinder

Methodology Applied
Scientific EffectForce detection: Force

Data Source

PatentEP3914402B1Rolling equipment and rolling method
Publication Date: 2025.09.24 PRIMETALS TECHNOLOGIES JAPAN LTD
  • EP3914402B1 patent drawingFigure 1
  • EP3914402B1 patent drawingFigure 2
  • EP3914402B1 patent drawingFigure 3

AI summary

Rolling equipment includes a strip wedge controller that obtains the distribution in the strip width direction of a strip load applied to a rolled material 5 from a work side load PW and a drive side load PD, that calculates the strip wedge after the rolling based on the distribution in the strip width direction of the strip load obtained and the position in the strip width direction of the rolled material 5 set by a rolled material position setting device, that computes a working roll gap difference between the work side and the drive side of a vertical pair of an upper working roll 21 and a lower working roll 31 for making the strip wedge after the rolling calculated a predetermined value, and that controls the drive side hydraulic cylinder 11D and the work side hydraulic cylinder 11W such that the working roll gap difference computed is attained.