Hot-rolled steel sheet cooling control with entry-side temperature measurement
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Solution Overview
Problem
Existing manufacturing methods for hot-rolled steel sheets struggle to accurately control the cooling temperature of steel sheets during rapid cooling, especially when the cooling device is positioned inside a hot finishing mill, making it difficult to measure the steel sheet's temperature between the mill and the cooling device.
Innovation Solution
A manufacturing apparatus and method that includes temperature measurement devices on both the entry and exit sides of the final stand in the hot finishing mill, along with a cooling control system that adjusts the cooling water volume and pressure to precisely control the rapid-cooling stopping temperature, using a combination of immediate rapid-cooling and hot-run cooling devices to ensure uniform cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cooling device is positioned inside the hot finishing mill to enable immediate rapid cooling, then the cooling capability and productivity are improved, but the measurement precision of steel sheet temperature becomes insufficient
Solution Approach 1:
The patent applies preliminary action by measuring the steel sheet temperature on the entry side of the water-cooling device before cooling begins. This advance measurement allows the control system to determine appropriate cooling conditions in advance, ensuring both immediate cooling capability and accurate temperature control for achieving the target coiling temperature.
2Speed
If the cooling water volume per unit area is increased to enhance cooling capability, then the cooling speed is improved, but the control precision of the stopping temperature becomes difficult to maintain
Solution Approach 1:
The patent implements feedback control by continuously monitoring the steel sheet temperature during the cooling process and adjusting the cooling water volume accordingly. The control system compares the measured temperature with the target temperature and modifies the cooling intensity in real-time, enabling both rapid cooling and precise control of the stopping temperature to achieve the desired metal structure.
Solution Approach 2:
The patent applies dynamics by making the cooling water volume adjustable and variable during the cooling process. Instead of using a fixed cooling rate, the system dynamically changes the water flow rate based on real-time temperature measurements and process conditions, allowing optimization of both cooling speed and temperature control precision throughout the cooling cycle.
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
Enables high-precision cooling control of steel sheets, allowing for the production of hot-rolled steel sheets with consistent mechanical properties and desired structures by accurately managing the cooling process, even when the cooling device is integrated within the finishing mill.
Implementation Method 1
spraying cooling water at a high-temperature steel sheet that has just been rolled in a hot finishing mill, to water-cool it
Implementation Method 2
cooling water volume per unit area sprayed over the steel sheet, that is, to increase a water flow density in order to enhance a cooling capability
Implementation Method 3
measuring a surface temperature of a steel sheet with a radiation thermometer after a certain amount of time passes from the time when the rapid cooling has been stopped
Implementation Method 4
the heat in the central area is diffused toward the surface layer area, as time passes, to become uniform
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention provide a manufacturing apparatus of a hot-rolled steel sheet capable of cooling control of a steel sheet even in a case of disposing a cooling device capable of cooling from inside a finishing mill. The manufacturing apparatus of a hot-rolled steel sheet comprises: an immediate rapid-cooling device 20, which is capable of spraying cooling water with a high water volume density, at least a part thereof being disposed inside a final stand in the row of hot finishing mills; a device 45 for measuring a temperature on an entry side of a final stand, which measures a surface temperature of a steel sheet on an entry side of the final stand; a device 47 for measuring a steel sheet passing speed, which measures a passing speed of the steel sheet on the entry side of the final stand; a device 51 for predicting a rapid-cooling stopping temperature, which calculates a predicted rapid-cooling stopping temperature based on the surface temperature of the steel sheet, the steel sheet passing speed, and the water supply volume or water supply pressure of the immediate rapid-cooling device respectively measured; and an immediate rapid-cooling control device 52, which corrects the water supply volume or water supply pressure of the immediate rapid-cooling device such that the predicted rapid-cooling stopping temperature matches a targeted rapid-cooling stopping temperature.