Metal Strip Pickling Control Using LIBS Oxide Measurement
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Solution Overview
Problem
Conventional strip cleaning processes for hot-rolled metal products are inefficient and wasteful, as they often use excessive amounts of acid to remove surface oxides, leading to reduced production capacity, increased material loss, and poor surface quality due to over-pickling or under-pickling, especially with the rise of advanced steel grades like non-grain oriented sheets.
Innovation Solution
A cleaning plant equipped with laser-induced breakdown spectroscopy (LIBS) for precise oxide layer measurement, gaseous hydrogen detection, and real-time process control to optimize pickling parameters, minimizing acid consumption and improving yield and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical pickling is used to remove oxide layers, then surface quality is improved, but material loss increases and production capacity decreases due to over-pickling or under-pickling
Solution Approach 1:
The system performs preliminary measurement of oxide layer thickness and composition using LIBS technology before the pickling process. This preliminary action provides accurate data that enables optimization of pickling parameters, preventing both over-pickling and under-pickling, thereby reducing material loss while maintaining surface quality
Solution Approach 2:
The system implements a feedback mechanism where real-time measurements of oxide layer characteristics are continuously fed back to adjust pickling parameters. This closed-loop control ensures optimal acid consumption and prevents excessive material removal, resolving the contradiction between surface quality and material loss
2Manufacturing precision
If conventional chemical pickling is used to remove oxide layers, then surface quality is improved, but production capacity decreases due to excessive acid consumption and process optimization needs
Solution Approach 1:
The system dynamically changes pickling parameters (acid concentration, temperature, exposure time) based on real-time oxide layer measurements. This parameter optimization enables faster pickling cycles with reduced acid consumption, thereby increasing production capacity while maintaining surface quality
Solution Approach 2:
The system replaces conventional mechanical/tactile oxide measurement methods with LIBS (laser-induced breakdown spectroscopy) technology. This substitution provides rapid, non-contact measurement that enables real-time process control, increasing production speed and capacity while maintaining quality
3Manufacturing precision
If advanced steel grades like non-grain oriented sheets are processed, then product quality is improved, but pickling process complexity increases and requires precise parameter control
Solution Approach 1:
The system uses the oxide layer itself as the source of control information through LIBS measurement. The oxide composition and thickness data automatically generated serve as direct feedback for parameter adjustment, eliminating the need for complex external sensing systems and simplifying process control for advanced steel grades
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 system maximizes production capacity, reduces material waste, and enhances product quality by accurately adjusting pickling conditions based on real-time data, ensuring optimal removal of surface oxides without damaging the base metal.
Implementation Method 1
measuring means for measuring the thickness of the surface oxide layer, arranged between said unwinding means and said chemical pickling means; wherein said measuring means comprise at least one laser source cooperating with an optical fiber spectrometer, defining a LIBS (Laser-Induced Breakdown Spectroscopy) system adapted to analyze the oxide composition in addition to thickness
Implementation Method 2
chemical pickling means for pickling said rolled strip
Data Source
AI summary
A cleaning plant for hot-rolled metal strips provided with a surface oxide layer, 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 surface oxide layer, arranged between said unwinding means and said pickling means; and wherein gaseous hydrogen detection means are provided to detect the presence of gaseous hydrogen in fumes produced by said pickling means. A corresponding cleaning method is also claimed.