Metal Strip Pickling Control Using LIBS Oxide Measurement
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Solution Overview
Problem
Conventional cleaning methods for hot-rolled metal strips are inefficient in removing the oxide layer, leading to material loss, environmental hazards, and suboptimal cleaning processes due to unknown initial scale thickness and excessive acid usage.
Innovation Solution
A cleaning plant equipped with laser-induced breakdown spectroscopy (LIBS) systems for precise measurement of oxide layer thickness and composition, allowing for automatic adjustment of pickling parameters and reduced acid consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional chemical pickling is used to remove oxide layers, then the oxide layer is removed, but excessive acid consumption and material loss occur
Solution Approach 1:
The system performs preliminary measurement of oxide layer thickness using LIBS technology before the pickling process. This allows the pickling parameters (acid concentration, exposure time, temperature) to be pre-calculated and optimized based on the actual oxide thickness, preventing both over-pickling (excessive material removal) and under-pickling (insufficient cleaning).
Solution Approach 2:
The system implements a feedback control loop where oxide layer thickness is measured in real-time, process parameters are automatically adjusted based on measurement results, and the cleaning effectiveness is continuously monitored. This closed-loop control ensures optimal acid usage and minimal material loss while maintaining consistent cleaning quality.
2Manufacturing precision
If conventional chemical pickling is used without precise measurement, then cleaning is performed, but process optimization is impossible due to unknown initial scale thickness
Solution Approach 1:
The system replaces conventional mechanical or visual inspection methods with LIBS (Laser-Induced Breakdown Spectroscopy) technology. A laser pulse is directed at the oxide layer, creating a plasma whose spectral emission lines provide precise information about oxide thickness and composition. This optical spectroscopy method enables non-contact, rapid, and highly accurate measurement of oxide layer characteristics.
Solution Approach 2:
The system utilizes changes in spectral parameters (intensity, wavelength, duration of emission lines) to determine oxide layer thickness and composition. By analyzing how these spectral parameters vary with oxide thickness, the system can precisely quantify the oxide layer and adjust pickling parameters accordingly to achieve optimal cleaning precision.
3Reliability
If excessive acid is used to ensure complete cleaning, then cleaning reliability is improved, but environmental harm and disposal costs increase
Solution Approach 1:
The system performs preliminary measurement and calculation of exact pickling parameters based on actual oxide thickness. This allows the minimum necessary amount of acid to be used while ensuring complete and reliable cleaning, eliminating the need for excessive acid application that would compromise environmental safety.
Solution Approach 2:
The system dynamically adjusts pickling parameters (acid concentration, flow rate, exposure time, temperature) based on real-time oxide thickness measurements. This parameter optimization ensures that cleaning reliability is maintained at the required level while minimizing acid consumption and environmental impact.
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 solution enables precise and safe cleaning with reduced material loss, environmental impact, and optimized acid usage, improving the quality and efficiency of the cleaning process.
Implementation Method 1
at least one laser source (4), arranged upstream of the pickling means (5), for ablation of the superficial layer of oxide
Implementation Method 2
The measuring means (4) consist of at least one laser source (4) cooperating with a fiber optic spectrometer, defining a LIBS system (Laser Induced Breakdown Spectroscopy)
Data Source
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AI summary
A plant for cleaning rolled metal strips provided with a superficial layer of oxide, the plant comprising unwinding means for unwinding at least one coil of rolled strip and pickling means for pickling said rolled strip; wherein there are provided measuring means for measuring the thickness of the superficial layer of oxide, arranged between said unwinding means and said pickling means. A relating cleaning method is also claimed.