Hot-Rolled Coil End-Face Temperature Prediction for Crack Prevention
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Solution Overview
Problem
The production of cold-rolled steel sheets is hindered by cracks at the end of the steel due to uneven coiling shapes, leading to potential rupture and increased costs for recovery operations, as well as facility failures.
Innovation Solution
A method is developed to predict the temperature history of the end face unevenness of hot-rolled coils by measuring surface temperatures, calculating a temperature history assuming no unevenness, and using a displacement meter to derive the size of the unevenness, allowing for the prediction of potential rupture during the cold rolling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the coil is cooled at normal speed, then the production efficiency is maintained, but the protruding part experiences accelerated cooling and forms hard phases causing cracks
Solution Approach 1:
The invention performs preliminary identification of protruding parts on the coil end face using a displacement meter before the steel enters the cooling region. By detecting the position and size of protrusions in advance, the system can predict which areas will experience accelerated cooling and form hard phases, allowing for preventive measures to be taken before cracking occurs
Solution Approach 2:
The invention changes the cooling speed parameter dynamically based on the detected protruding parts. Specifically, the cooling speed is reduced in regions where protruding parts are identified, preventing the accelerated cooling that would otherwise cause hard phase formation and cracking. This localized parameter adjustment resolves the contradiction between maintaining overall production efficiency and preventing localized damage
2Reliability
If the cooling speed is reduced to prevent hard phase formation, then crack prevention is improved, but production efficiency decreases
Solution Approach 1:
The invention applies different cooling speeds to different regions of the coil based on local conditions. Protruding parts are identified using a displacement meter, and only the regions containing these protrusions receive reduced cooling speed. The rest of the coil continues to cool at normal speed, maintaining production efficiency while preventing cracks only where necessary
Solution Approach 2:
The invention creates a virtual model of the coil end face by scanning it with a displacement meter to identify protruding parts. This copied information about the coil geometry is then used to predict temperature history and determine where cooling speed adjustments are needed, allowing for precise localized control without affecting the entire coil
3Device complexity
If the end face unevenness is not detected, then the measurement process is simple, but the crack prediction and prevention capability is lost
Solution Approach 1:
The invention replaces complex manual inspection methods with an automated displacement meter scanning system. The displacement meter mechanically scans the coil end face to detect protruding parts, and this mechanical measurement is automatically processed to create a virtual model and predict temperature history. This substitution provides accurate crack prediction capability while keeping the measurement process relatively simple and automated
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 method enables the prediction of temperature history and potential rupture of the steel, allowing for proactive measures to prevent cracks and improve production efficiency by identifying and addressing unevenness in the coiling process.
Implementation Method 1
scanning with a displacement meter, an end face of a coil formed in the coiling step
Implementation Method 2
measuring a surface temperature of hot-rolled strip-shaped steel
Implementation Method 3
cooling a thus obtained coil to around normal temperature
Implementation Method 4
cooling a thus obtained coil to around normal temperature
Data Source
AI summary
A method for producing a hot-rolled steel sheet which enables predicting a temperature history of unevenness of the end face of a coil includes: measuring a surface temperature of hot-rolled strip-shaped steel; calculating a temperature history in a natural cooling state after coiling, assuming that the strip-shaped steel has been coiled without unevenness on an end face, based on the surface temperature measured in the measurement step; actually coiling the strip-shaped steel after the measurement step; scanning with a displacement meter, an end face of a coil formed in the coiling step, and deriving a size of the unevenness of the end face over a radius of the coil; and predicting a temperature history of the unevenness in a natural cooling state using: the temperature history calculated in the first calculation step; and the size of the unevenness derived in the derivation step.