Rolling Steel Cooling System with Rectifying Plate

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Solution Overview

Problem

Conventional accelerated cooling methods for high-carbon rail steel result in variations in cooling rate due to vapor film formation, leading to potential deviations in steel microstructure and reduced toughness and ductility.

Innovation Solution

A cooling system with chambers that mix compressed air and cooling water, using a nozzle plate with nozzle holes to spray the cooling medium perpendicular to the steel bar, and a rectifying plate to ensure uniform gas flow, preventing vapor film formation and maintaining consistent cooling rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If liquid cooling medium is used for accelerated cooling, then cooling rate is improved, but vapor film formation causes cooling rate variation and temperature deviation

Engineering Contradiction:
Improvecooling rateVSAvoidcooling rate uniformity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces compressed gas as an intermediary substance between the liquid cooling medium and the steel bar surface. The compressed gas breaks the vapor film barrier that forms during liquid cooling, allowing the liquid cooling medium to contact the surface more effectively and uniformly, thereby maintaining high cooling rate while improving uniformity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state and flow parameters of the cooling medium by introducing compressed gas. This creates a two-phase flow system where gas pressure and velocity parameters are controlled to optimize the breakdown of vapor films and enhance liquid cooling medium distribution, resolving the contradiction between cooling rate and uniformity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If gas cooling medium is used for accelerated cooling, then cooling rate uniformity is improved, but cooling rate becomes slower

Engineering Contradiction:
Improvecooling rate uniformityVSAvoidcooling rate
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent merges the advantages of both gas and liquid cooling mediums into a single integrated system. The compressed gas provides uniform distribution and vapor film breakdown, while the liquid cooling medium provides high heat transfer coefficient, achieving both high cooling rate and good uniformity simultaneously

Inventive Principle:
Principle #5Merging (Combining)

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 enables stable and uniform accelerated cooling, reducing temperature deviations and maintaining microstructure consistency, thereby enhancing the abrasion resistance and mechanical properties of the rail steel.

Implementation Method 1

mixing the compressed gas for cooling and the cooling water

Methodology Applied
Scientific EffectMixing:

Implementation Method 2

spraying a cooling medium that is produced by mixing the cooling water that is supplied from the cooling water supply nozzle and the compressed gas for cooling that is introduced from the gas inlet and rectified by the rectifying plate toward the rolled steel bar through the nozzle holes of the nozzle plate

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 3

a rectifying plate that is provided between the gas inlet and the cooling water supply nozzle, and that prevents the compressed gas for cooling that is introduced from the gas inlet from directly striking the nozzle plate

Methodology Applied
Scientific EffectFlow rectification:

Implementation Method 4

the Leidenfrost phenomenon occurs in which a vapor film is formed between the droplet and the high-temperature body, and the droplet floats on the high-temperature body. In the case of using the methods of (1) and (3) that employ a liquid for the cooling medium, due to the vapor film that is formed on the rail surface, contact between the rail and the cooling medium is hindered

Methodology Applied
Scientific EffectVapor film suppression: Leidenfrost Effect

Data Source

PatentEP2253394B1Cooling system and cooling method of rolling steel
Publication Date: 2018.04.04 NIPPON STEEL & SUMITOMO METAL CORP
  • EP2253394B1 patent drawingFigure 1
  • EP2253394B1 patent drawingFigure 2~3
  • EP2253394B1 patent drawingFigure 4A~4B

AI summary

A cooling system that cools hot rolled long steel bar, provided with a plurality of chambers that are arranged along the longitudinal direction of the rolled steel bar. Each of the plurality of chambers is provided with a blow outlet that, facing from the chamber to the rolled steel bar, blows out compressed air for cooling that is introduced to the chamber from a gas inlet that is connected to the chamber; a nozzle plate having a plurality of nozzle holes that is provided at this blow outlet so as to face the rolled steel bar; a cooling water supply nozzle that supplies cooling water into the chamber; and a rectifying plate that is provided between the gas inlet and the cooling water supply nozzle, and that prevents the compressed gas for cooling that is introduced from the gas inlet from directly striking the nozzle plate. The cooling system of the present invention sprays a cooling medium that is produced by mixing the cooling water that is supplied from the cooling water supply nozzle and the compressed gas for cooling that is introduced from the gas inlet and rectified by the rectifying plate toward the rolled steel bar through the nozzle holes of the nozzle plate, and performs uniform cooling of the surfaces of the rolled steel bar.