Nitrogen Analysis in Steel Using Argon Discharge Optical Emission
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Solution Overview
Problem
Current methods for analyzing nitrogen in metal samples, such as inert gas fusion thermal conductivity detection, face challenges including accuracy issues due to coexisting gases like argon, and the high cost and scarcity of helium, which affects the reliability and cost-effectiveness of nitrogen determination in steel production.
Innovation Solution
A method using discharge optical emission analysis in an argon gas atmosphere to determine nitrogen content, where nitrogen gas is melted and analyzed, utilizing specific wavelengths for accurate detection and correcting for argon gas interference, thereby eliminating the need for helium and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inert gas fusion thermal conductivity detection method is used, then analysis rapidness is improved, but measurement precision deteriorates due to coexisting gases interference
Solution Approach 1:
The patent extracts and removes coexisting gases (CO, H2, CO2, H2O) from the gas stream before analysis. This is achieved through specific gas removal units that selectively eliminate interfering gases, allowing the thermal conductivity detector to accurately measure only nitrogen content without interference from other gases generated during steel sample melting.
Solution Approach 2:
The patent introduces a carrier gas (helium or nitrogen) as an intermediary medium. The carrier gas transports the generated gases through the analysis system and serves as a reference for thermal conductivity measurements. By using a known carrier gas with stable thermal conductivity properties, the system can accurately determine nitrogen content even in the presence of other gases.
2Measurement precision
If helium is used as carrier gas, then measurement precision is improved, but device complexity and cost increase due to helium scarcity and expense
Solution Approach 1:
The patent changes the carrier gas parameter from helium to nitrogen. By substituting the carrier gas type, the system eliminates dependence on scarce and expensive helium while maintaining analysis capability. The patent provides conversion formulas to calculate nitrogen content in steel samples regardless of whether helium or nitrogen is used as carrier gas, thus simplifying the gas supply system and reducing costs.
3Measurement precision
If coexisting gases are removed through oxidation column and reagents, then measurement precision is improved, but loss of substance increases due to reagent consumption and periodic replacement
Solution Approach 1:
The patent extracts and removes coexisting gases (CO, H2, CO2, H2O) from the gas stream before analysis. This is achieved through specific gas removal units that selectively eliminate interfering gases, allowing the thermal conductivity detector to accurately measure only nitrogen content without interference from other gases generated during steel sample melting.
Solution Approach 2:
The patent employs reagents such as sodium hydroxide solution for CO2 removal and magnesium perchlorate for water vapor removal. These reagents are consumed during the analysis process and require periodic replacement to maintain analysis accuracy. The system design accepts this consumable loss as necessary for achieving precise nitrogen measurements.
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 allows for accurate and cost-effective determination of nitrogen content in metal samples, ensuring precise nitrogen concentration adjustment in steel manufacturing, reducing the impact of argon gas interference and eliminating the high costs associated with helium use.
Implementation Method 1
a melting process in which a metal sample containing a nitrogen component is melted in an argon gas atmosphere by performing impulse heating to gasify the nitrogen component
Implementation Method 2
an analyzing process in which nitrogen content in the metal sample is determined by analyzing nitrogen gas generated in the melting process and the argon gas by using a gas discharge optical emission method
Data Source
AI summary
Provided are a method for analyzing nitrogen in a metal sample, an apparatus for analyzing nitrogen in a metal sample, a method for adjusting nitrogen concentration in molten steel, and a method for manufacturing steel. The method includes: a melting process in which a metal sample containing a nitrogen component is melted in an argon gas atmosphere by performing impulse heating to gasify the nitrogen component; and an analyzing process in which nitrogen content in the metal sample is determined by analyzing nitrogen gas generated in the melting process and the argon gas by using a gas discharge optical emission method. By analyzing the nitrogen concentration of a sample taken from molten steel by using the analysis method described above, and by determining treatment conditions for adjusting nitrogen concentration on the basis of the nitrogen analysis value derived by the analysis, nitrogen concentration in molten steel is adjusted.