Movable Hot Coil Insulation for Online Heat Treatment Uniformity

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Solution Overview

Problem

Traditional hot-rolling processes face challenges with uneven cooling and excessive air cooling after rolling, leading to performance fluctuations and degraded plate shape quality in high-strength steel, which are not adequately addressed by existing off-line thermal insulation methods that increase manufacturing costs and prolong production cycles.

Innovation Solution

Implementing an on-line movable thermal insulation heat treatment process where a thermal insulation device is applied directly to the hot coil immediately after coiling, allowing for continuous heat treatment during transportation using a transport cart with a thermal insulation enclosure, leveraging the residual heat of the steel coil for efficient soaking and slow cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If off-line heat treatment using thermal insulation pits or walls is used after coiling, then thermal insulation is achieved, but the time interval for thermal insulation is too long (30-120 minutes) allowing uneven cooling to occur first

Engineering Contradiction:
Improvethermal insulation effectivenessVSAvoidtime interval between coiling and thermal insulation
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent applies thermal insulation immediately after coiling while the steel coil is still hot, performing the thermal insulation action in advance before uneven cooling can occur. The transport cart with thermal insulation enclosure is positioned to receive the coil directly from the coiling machine, eliminating the delay of transporting to a separate finishing warehouse.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent combines the coiling process and thermal insulation process into a single integrated operation. The thermal insulation enclosure is applied to the coil on the transport cart immediately after coiling, merging what were previously separate off-line operations into a continuous on-line process.

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If thermal insulation pits or walls are used for slow cooling, then thermal insulation is provided, but no heat source is available to maintain temperature

Engineering Contradiction:
Improvetemperature maintenanceVSAvoidheat loss during cooling
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent utilizes the residual heat already present in the hot steel coil as the heat source for the thermal insulation process. The coil's own thermal energy is sufficient to maintain the required temperature during the insulation period, eliminating the need for external heating systems while minimizing energy loss.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If a roller hearth furnace or bell furnace is used for heat treatment, then uniform heat treatment is achieved, but huge one-time project investment is required

Engineering Contradiction:
Improveheat treatment uniformityVSAvoidequipment investment cost
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive, complex fixed heat treatment furnaces with a simpler, movable thermal insulation enclosure on a transport cart. This disposable-style approach uses readily available insulation materials and standard transport equipment rather than specialized industrial furnaces, dramatically reducing investment costs while achieving sufficient heat treatment uniformity for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent introduces a thermal insulation enclosure as an intermediary device between the coiling process and the final product storage. This enclosure provides the necessary thermal insulation function without requiring a full-scale heat treatment furnace, serving as a cost-effective intermediate solution that achieves the required heat treatment uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If reheating is performed in a roller hearth furnace or bell furnace, then uniform heat treatment is achieved, but manufacturing cost and manufacturing cycle are significantly increased

Engineering Contradiction:
Improveheat treatment qualityVSAvoidmanufacturing cycle time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs thermal insulation immediately after coiling while the steel coil is still at the required temperature, eliminating the need for subsequent reheating operations. This preliminary action saves both time and energy while maintaining heat treatment quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous thermal insulation from the moment of coiling through transportation and storage, ensuring the heat treatment process occurs continuously without interruption or the need for reheating, thereby reducing manufacturing cycle time while maintaining quality.

Inventive Principle:
Principle #20Continuity of useful action

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 improves product performance and plate shape quality, reduces energy consumption, and enhances production efficiency by minimizing the interval between coiling and thermal insulation, thus meeting the requirements for high-strength steel while maintaining high-speed large-scale production capabilities.

Implementation Method 1

a thermal insulation device is applied directly to the hot coil immediately after coiling

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the movable hot coil thermal insulation heat treatment device is placed on the transport cart

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3685931B1Hot-rolling online movable thermal insulation heat treatment process, and heat treatment line
Publication Date: 2023.08.23 BAOSTEEL ZHANJIANG IRON & STEEL CO LTD

AI summary

A hot rolling online movable thermal insulation heat treatment process, and a heat treatment line. The heat treatment process comprises: heating, rolling, layer-cooling, and reeling a slab into a hot coil state; assembling a movable hot coil thermal insulation heat treatment apparatus (40) for the hot coil in 30 minutes after the hot coil is unloaded and bundled, performing heat treatment on the hot coil, and conveying the hot coil to a hot coil thermal insulation treatment area online; after 1 to 48 hours of heat treatment, cooling the hot coil by means of air cooling and then conveying the steel coil to storage. The coiling temperature is controlled between 250°C to 750°C. The heat treatment process is effectively combined with a hot coiling process, and a hot coil is subjected to high efficient thermal insulation heat treatment in the first place; the hot coil subjected to the thermal insulation treatment moves online with the thermal insulation apparatus. Time-based differentiated requirements on the heat treatment process are met, product performance can be effectively improved, investment costs in one time are low, demands for mass production is satisfied, and energy is saved.