Hot-Rolled Steel Sheet Cooling with Non-Overlapping Spray Zones

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Solution Overview

Problem

Conventional cooling methods for hot-rolled steel sheets after finish rolling result in uneven cooling due to overlapping collision regions of cooling water, leading to ununiform temperature distribution and potential damage from intermittent contact with rolls.

Innovation Solution

A method and apparatus where cooling water is jetted from spray nozzles positioned on both lateral sides of the steel sheet conveyance region, with pairs of nozzles aligned in the conveyance direction, ensuring that collision regions do not overlap, and meetings are formed within a meeting zone to cover the entire width direction uniformly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cooling water is jetted from spray nozzles positioned on both lateral sides of the steel sheet conveyance region, then cooling uniformity in the width direction is improved, but collision regions of cooling water may overlap causing overcooling at certain positions

Engineering Contradiction:
Improvecooling uniformityVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The patent applies local quality by adjusting the spray characteristics of nozzles at different positions. Specifically, nozzles at different lateral positions have different spray angles and water flow rates tailored to their location, ensuring that collision regions do not overlap and overcooling is prevented while maintaining uniform cooling across the width direction

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes parameters such as spray angle, water flow rate, and nozzle positioning to optimize cooling uniformity. By adjusting these parameters for each nozzle based on its position, the collision regions are controlled to avoid overlap, thereby achieving uniform temperature distribution without overcooling

Inventive Principle:
Principle #35Parameter changes

2Temperature

If cooling water is jetted to cool the hot-rolled steel sheet, then cooling performance is improved, but on-sheet water remains on the steel sheet causing ununiform cooling

Engineering Contradiction:
Improvecooling performanceVSAvoidcooling uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent extracts the harmful element (on-sheet water) by introducing separate water removal nozzles that jet high-velocity water to remove excess cooling water from the steel sheet surface. This separation of cooling and water removal functions ensures uniform cooling without the detrimental effects of on-sheet water accumulation

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If high-pressure water is jetted to remove cooling water from the steel sheet, then water removal capability is improved, but cooling uniformity deteriorates due to overlap of collision regions

Engineering Contradiction:
Improvewater removal capabilityVSAvoidcooling uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies multi-functionality by designing nozzles that serve dual purposes: cooling nozzles jet cooling water at controlled angles and rates, while water removal nozzles jet high-velocity water to remove on-sheet water. Both functions are integrated into the same lateral positioning system, allowing coordinated operation to achieve both effective water removal and uniform cooling without collision region overlap

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 ensures uniform cooling of the hot-rolled steel sheet in the width direction, preventing overcooling and damage, and allows for efficient water removal, improving the mechanical properties and formability of the steel sheet.

Implementation Method 1

cooling water is jetted from spray nozzles positioned on both lateral sides of the steel sheet conveyance region

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

cooling is conducted using the cooling water having a water flow density that causes nuclear boiling

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3363552B1Method and apparatus for cooling hot-rolled steel sheet
Publication Date: 2022.07.13 NIPPON STEEL CORPORATION
  • EP3363552B1 patent drawingFigure 1
  • EP3363552B1 patent drawingFigure 2
  • EP3363552B1 patent drawingFigure 3

AI summary

A hot-rolled steel sheet is cooled by jetting cooling water from spray nozzles to a steel sheet conveyance region in a width direction of the steel sheet conveyance region. The steel sheet conveyance region is a region that the hot-rolled steel sheet occupies on conveyor rolls, a pair of spray nozzles is arranged on both lateral sides in the width direction of the steel sheet conveyance region, and a plurality of spray nozzle pairs are aligned in a conveyance direction of the hot-rolled steel sheet. In regard to a collision region of cooling water jetted from the spray nozzle at the steel sheet conveyance region, a far end in a jet direction is positioned at an end of the steel sheet conveyance region, and a near end is positioned on an inner side of the steel sheet conveyance region. In the spray nozzle pair, the near ends of two collision regions coincide in the width direction to form a meeting.