Hot-Rolled Steel Sheet Cooling with Overlapping Widthwise Water Jets
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Solution Overview
Problem
Existing cooling devices for hot-rolled steel sheets struggle to achieve uniform temperature distribution in both the conveyance direction and width direction, leading to nonuniform cooling and difficulties in controlling the coiling temperature, which affects the mechanical properties and workability of the steel sheets.
Innovation Solution
A cooling device that divides the cooling region into width-divided cooling zones and divided cooling surfaces, with cooling water nozzles inclined to jet water opposite to their initial direction, forming overlapping collision regions to enhance heat transfer and uniform cooling, and a control system that adjusts the cooling based on temperature measurements to cover the entire width direction effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cooling water is jetted to the steel sheet at high temperature (800°C to 900°C), then uniform cooling of the entire surface is facilitated due to stable steam film coverage, but the cooling capacity becomes small when the temperature drops below 600°C
Solution Approach 1:
The invention dynamically adjusts the cooling water flow rate based on the steel sheet temperature. When temperature is above 600°C, a lower flow rate maintains steam film stability. When temperature drops below 600°C, the flow rate is increased to enhance cooling capacity. This dynamic adjustment resolves the contradiction between maintaining uniform cooling through steam film and ensuring sufficient cooling capacity at lower temperatures.
Solution Approach 2:
The invention changes the parameter of cooling water flow rate according to temperature conditions. By varying this parameter (flow rate) based on the steel sheet temperature, the system adapts to different thermal states, achieving both uniform cooling at high temperatures and sufficient cooling capacity at lower temperatures.
2Power
If the steam film covering the surface breaks when temperature is below 600°C, then the cooling capacity increases, but the nonuniformity in cooling increases and temperature distribution becomes nonuniform
Solution Approach 1:
The invention applies different cooling strategies to different regions of the steel sheet. Temperature sensors detect local temperature variations, and the control system adjusts cooling water flow rates for specific zones. This local quality approach ensures that regions with broken steam films receive enhanced cooling control to maintain uniform temperature distribution across the entire sheet.
Solution Approach 2:
The invention implements a feedback control system where temperature sensors continuously monitor the steel sheet temperature distribution, and the control system adjusts cooling water flow rates based on this feedback. When the steam film breaks and causes temperature nonuniformity, the feedback mechanism detects this and adjusts the cooling water application to restore uniform temperature distribution.
3Stability of the object's composition
If cooling water nozzles are arranged to cover the entire width direction, then the uniformity of coiling temperature is improved, but the complexity of the cooling device increases
Solution Approach 1:
The invention segments the cooling device into multiple independent nozzle units distributed across the width direction. Each nozzle unit can be independently controlled based on local temperature requirements. This segmentation allows comprehensive width-direction coverage while managing device complexity through modular, independently controllable units rather than a single complex system.
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 significantly improves the uniformity of temperature distribution across the hot-rolled steel sheet, ensuring consistent mechanical properties and workability by optimizing the cooling process in both the conveyance and width directions.
Implementation Method 1
at least one cooling water nozzle which jets cooling water to form a cooling water collision region on the top surface of the cooling target region
Implementation Method 2
the single cooling water collision region overlaps the another cooling water collision region adjacent thereto in the width direction
Data Source
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AI summary
The present cooling device includes: when cooling regions obtained by dividing an entire cooling region into a plurality of portions in a steel sheet conveyance direction and three or more portions in a width direction are set as divided cooling surfaces, a cooling water nozzle 23 and a switching device that switches between collision and non-collision of cooling water jetted from the cooling water nozzle 23 with the divided cooling surface, the cooling water nozzle 23 and the switching device provided for each of the divided cooling surfaces; and a control device that controls operation of the switching device based on a width-direction temperature distribution. The cooling water nozzle 23 has a jet axis P inclined with respect to a vertical line to the entire cooling region when viewed in the steel sheet conveyance direction, and the cooling water goes to the side opposite to the cooling water nozzle 23 in the width direction after colliding with the divided cooling surface.