Reversing Hot-Rolling With Plate Segmentation and Temperature Holding

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Solution Overview

Problem

Reversing rolling processes in metal plate manufacturing face limitations due to heat loss and increased deformation resistance as metal plates are rolled to thinner thicknesses, restricting the final thickness and length of hot-rolled metal plates that can be produced, and existing solutions like Steckel mills are complex and costly.

Innovation Solution

A method involving re-heating a metal slab to a rolling temperature, rolling it to an intermediate thickness, shearing it into multiple plates, and using a temperature-holding device to maintain the temperature of divided plates before re-rolling them to the final thickness, thereby minimizing heat loss and maintaining uniform temperature distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the metal plate is rolled to a thinner final thickness in a reversing rolling mill, then the plate can achieve greater elongation in length, but heat loss increases and temperature decreases, making it impossible to maintain required tolerances

Engineering Contradiction:
Improvemetal plate lengthVSAvoidmetal plate temperature
Core Design Contradiction:
Length of moving objectVSTemperature

Solution Approach 1:

The metal plate is divided into multiple sections along its length, with heating zones positioned at specific intervals. Each section is independently heated to compensate for heat loss in that specific region, allowing the entire plate to maintain uniform temperature throughout the rolling process despite increased length

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The metal plate is pre-heated to rolling temperature before entering the reversing rolling mill, and heating zones continue to supply heat during the rolling process. This preliminary and continuous heating ensures the plate maintains adequate temperature throughout the entire rolling operation, enabling production of longer plates at thinner gauges

Inventive Principle:
Principle #10Preliminary action

2Length of moving object

If the metal plate is rolled to a thinner final thickness, then the surface area of the metal plate increases, but the rate of heat loss and temperature decrease accelerates

Engineering Contradiction:
Improvemetal plate lengthVSAvoidheat loss from metal plate
Core Design Contradiction:
Length of moving objectVSLoss of energy

Solution Approach 1:

Heating zones are strategically positioned at specific locations along the metal plate where heat loss is most critical. Each heating zone provides localized thermal energy to its corresponding plate section, creating a non-uniform heating distribution that compensates for the non-uniform heat loss pattern across the plate surface

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The increased surface area, which normally accelerates heat loss, is countered by introducing heating zones that convert electrical or thermal energy directly into the plate at critical locations. This transforms the harmful heat loss effect into a controlled thermal management system where heat is added precisely where needed

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If the metal plate temperature decreases, then the deformation resistance of the metal plate increases, but this makes it impossible to proceed with the rolling process while keeping final thickness within required tolerances

Engineering Contradiction:
Improvefinal thickness toleranceVSAvoidroll force required
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The metal plate is pre-heated to the appropriate rolling temperature before entering the reversing rolling mill. This preliminary heating ensures the plate has adequate thermal energy to undergo plastic deformation at the required roll forces, enabling achievement of precise final thickness tolerances without excessive force requirements

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The temperature of the metal plate is maintained within an optimal range throughout the rolling process by using heating zones. By controlling the thermal parameter of the plate, the deformation resistance is kept at acceptable levels, allowing the rolling process to proceed smoothly and achieve required thickness tolerances

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 method allows for the production of thinner metal plates with greater maximum length and improved uniformity, increasing process efficiency and productivity while reducing the need for complex and costly equipment like Steckel mills.

Implementation Method 1

using a temperature-holding device to maintain the temperature of divided plates before re-rolling them to the final thickness, thereby minimizing heat loss and maintaining uniform temperature distribution

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

re-heating a metal slab to a rolling temperature

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP3711873B1Method and hot-rolling equipment
Publication Date: 2022.07.20 SSAB TECHNOLOGY AB
  • EP3711873B1 patent drawingFigure 1
  • EP3711873B1 patent drawingFigure 2

AI summary

Method for manufacturing a plurality of hot-rolled metal plates comprising the steps of reheating a metal slab (15) to a rolling temperature, rolling the metal slab (15) in a reversing rolling mill (12) to produce a metal plate (16) having an intermediate thickness (h1), and shearing the metal plate (16) to divide it into a first divided metal plate (18) and at least a second divided metal plate (20). The method comprises the steps of hot-rolling the first divided metal plate (18) to a final thickness (hf) in the reversing rolling mill (12), transferring at least the second divided metal plate (20) to a temperature-holding device (22) to maintain it/them at a desired temperature while the first divided metal plate (18) is rolled to the final thickness (hf) in the reversing rolling mill (12), and transferring said second divided metal plate (20) from said temperature-holding device (22) to said reversing rolling mill (12) once said first divided metal plate (18) has been rolled to said final thickness (hf), and rolling the second divided metal plate (20) to a final thickness (hf) in the reversing rolling mill (12).