Cold Rolling Facility Meandering Control and Edge Heating

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Solution Overview

Problem

Conventional cold rolling facilities face challenges in stabilizing the overlapping length of steel sheets during induction heating, leading to underheating or abnormal local heating, which results in steel-sheet fractures due to edge cracks or drawing fractures, thereby reducing production efficiency.

Innovation Solution

A cold rolling facility with a meandering-amount measuring unit and a shape measuring unit to correct meandering movement and shape issues, combined with a heating device using C-shaped inductors for precise induction heating, ensures optimal overlapping length control and stable heating of steel sheet edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the steel sheet is cold-rolled at room temperature, then the handling and labor environment are improved, but edge cracks occur in the steel sheet during rolling

Engineering Contradiction:

Improvehandling of steel sheetVSAvoidedge crack occurrence

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The edge portions of the steel sheet are heated to 60°C or higher before cold rolling to prevent edge cracks during the rolling process. This preliminary heating action modifies the material properties at the edge portions, making them more ductile and resistant to cracking during subsequent cold rolling operations.

Inventive Principle:

Principle #10Preliminary action

2Temperature

If induction heating is used to heat the edge portion, then the edge temperature increases to prevent cracks, but the overlapping length becomes unstable causing underheating or abnormal local heating

Engineering Contradiction:

Improveedge portion temperatureVSAvoidoverlapping length control

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

A feedback control system is implemented that detects the actual position of the steel sheet edge portion during induction heating and adjusts the heating parameters accordingly. This feedback mechanism compensates for meandering movement and maintains stable overlapping length, preventing both underheating and abnormal local heating while ensuring uniform edge temperature.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical positioning systems with non-contact measurement and control systems. Optical sensors or other detection devices monitor the edge position without physical contact, and this information is used to control the induction heating parameters, eliminating the need for complex mechanical positioning mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If the overlapping length decreases during induction heating, then the meandering movement is reduced, but the edge portion is underheated

Engineering Contradiction:

Improveoverlapping length stabilityVSAvoidedge portion temperature

Core Design Contradiction:

Stability of the object's compositionVSTemperature

Solution Approach 1:

The system dynamically changes heating parameters including power level, frequency, and duration based on real-time detection of overlapping length and edge position. When overlapping length decreases, the system compensates by adjusting heating intensity and duration to maintain the required edge temperature, preventing underheating while accounting for reduced heat transfer efficiency.

Inventive Principle:

Principle #35Parameter changes

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 significantly reduces steel-sheet fractures by maintaining optimal edge temperatures, enhancing the stability and efficiency of the cold rolling process.

Implementation Method 1

a high frequency current is sent to the coil of the C-shaped inductor from a power unit to apply magnetic fluxes to the edge portions in the thickness direction of the steel sheet and generate an induced current in the edge portions

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the edge portions are heated with the Joule heat that occurs by the induced current

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS10259027B2Cold rolling facility and cold rolling method

Publication Date: 2019.04.16 JFE STEEL CORP

AI summary

A cold rolling facility includes: a heating device; a tandem mill including a plurality of rolling mills; a meandering-amount measuring unit; a meandering-movement correction device; a shape measuring unit; a shape controller configured to control a shape of a steel sheet after being cold-rolled by the rolling mill located on the uppermost stream side; and a controller configured to control operations of the meandering-movement correction device based on a measurement value of a meandering-movement amount of the steel sheet by the meandering-amount measuring unit to control a meandering movement of the steel sheet before being heated, and configured to control operations of the shape controller based on a measurement value of a shape of the steel sheet by the shape measuring unit to control the meandering movement of the steel sheet that is attributed to cold rolling of the steel sheet by the tandem mill.