Steel Sheet Cooling Edge Structure to Prevent Blowing Marks

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Solution Overview

Problem

The existing cooling processes for steel sheets, particularly those plated with zinc or zinc-alloys, face inefficiencies in cooling efficiency and often result in surface defects like blowing marks due to uneven fluid flow, which limits production efficiency.

Innovation Solution

An apparatus with stepped edge bodies and dimple regions is designed to manage the flow of cooling fluid, ensuring it is discharged efficiently away from the steel sheet's edges, reducing surface defects and enhancing cooling efficiency by maintaining a consistent fluid pressure and flow rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water or air is supplied to perform strong cooling within an allowable cooling process period, then cooling efficiency is improved, but a large amount of cooling fluid is used and surface defects such as blowing marks occur on the edge of the steel sheet

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsurface defects
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The apparatus applies different structural characteristics to different regions: the central region has a uniform cross-section for stable cooling, while the edge regions have stepped cross-sections with inclined surfaces to redirect cooling fluid flow away from the edges, preventing blowing marks while maintaining cooling efficiency in the center

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The edge bodies are designed with stepped cross-sections that create inclination angles, transforming the cooling fluid flow direction from a horizontal path along the edge to an angled path that directs fluid away from the steel sheet edge, thereby preventing surface defects

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the cooling process is performed during conveyance or post-processing, then production efficiency is improved, but the cooling process period is significantly limited

Engineering Contradiction:
Improveproduction efficiencyVSAvoidcooling process period
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The apparatus uses a high-velocity jet of cooling fluid (water or air) to achieve rapid cooling within the limited conveyance time, utilizing fluid dynamics to maximize heat transfer efficiency during the brief period the steel sheet is in motion through the apparatus

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Temperature

If the cooling fluid flow rate is increased toward the edge of the steel sheet, then cooling efficiency is improved, but surface defects such as blowing marks occur on the edge

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsurface quality
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The apparatus provides differentiated cooling: the central region receives high-velocity cooling fluid for efficient cooling, while the edge regions have stepped structures that redirect the fluid flow away from the edges, preventing blowing marks while maintaining overall cooling efficiency

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The stepped cross-section design with inclination angles redirects the cooling fluid flow from a path that would directly impact the edges to an angled path that directs fluid away from the edge regions, eliminating the cause of surface defects while preserving cooling effectiveness in the main body

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The apparatus improves cooling efficiency and surface quality of steel sheets by reducing the time cooling fluid remains on the edges, preventing defects and enhancing production efficiency without enlarging equipment.

Implementation Method 1

water or air (hereinafter referred to as 'cooling fluid') may be supplied to a steel sheet to perform strong cooling

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

Since the cooling fluid colliding with the surface of the steel sheet is discharged along an edge of the steel sheet in a width direction, a flow rate of the cooling fluid tends to be increased in a direction toward the edge of the steel sheet

Methodology Applied
Scientific EffectFluid flow: Convection

Data Source

PatentEP3892747B1Apparatus for cooling steel sheet
Publication Date: 2024.09.25 POSCO HLDG INC
  • EP3892747B1 patent drawingFigure 1
  • EP3892747B1 patent drawingFigure 2
  • EP3892747B1 patent drawingFigure 3

AI summary

An apparatus for cooling a steel sheet according to the present invention comprises: an apparatus body provided spaced apart from a steel sheet in the conveying path of the steel sheet; and a cooling unit provided in the apparatus body to supply a cooling fluid. The apparatus body includes: a first edge body that faces a first edge portion extending a certain distance from one side end of the steel sheet toward the center of the steel sheet; and a second edge body that faces a second edge portion extending a certain distance from the other side end of the steel sheet toward the center of the steel sheet. The first and second edge bodies may have stepped cross-sections in a direction perpendicular to the conveying direction of the steel sheet.