Analysis of Stainless Steels (Corrosion and Heat-Resistant Steels)

Importance of the Topic

Stainless steels represent a key category of ferrous alloys valued for their resistance to corrosion and high temperatures. Precise control of alloying elements such as chromium, nickel, carbon, manganese, molybdenum and copper determines material performance and cost. Reliable compositional analysis supports quality assurance, specification compliance and cost optimization in production and application of stainless steels.

Objectives and Study Overview

This performance note evaluates the capabilities of an atomic emission spectrometer employing a glow discharge source for rapid and accurate elemental analysis of stainless steel grades. The study compares measured concentrations against certified reference values for multiple standard materials to demonstrate accuracy, precision and dynamic range.

Methodology and Used Instrumentation

Sample preparation involved abrasive belt grinding or polishing to create a smooth surface for analysis. The glow discharge system uses sputtering to remove matrix material, separating sampling from excitation and reducing historical effects in the sample. Ground state atom emission simplifies spectra and minimizes interference in high alloy matrices. Calibration employed certified reference materials from recognized providers and factory installed steel calibrations. Drift control was maintained using homogeneous non certified standards.

Used Instrumentation

• Glow discharge atomic emission spectrometer model GDS500A
• Zirconium oxide belt grinder and polishing disk
• Sample surface preparation accessories (belt grinder and polisher)

Main Results and Discussion

Analysis of several standard materials, including grades 316, 317L, 17 4 PH, 303, 416, A286 and CN 7M, produced average values in close agreement with certified compositions. Relative standard deviations for major alloying elements were generally below one percent, demonstrating high precision. Calibration curves exhibited linear behavior across a broad concentration range, and the glow discharge source showed no cross contamination or sample melting when analyzing volatile elements such as sulfur.

Benefits and Practical Application

The glow discharge approach enables rapid multi element quantification with minimal sample handling. Ability to perform successive analyses without repositioning improves throughput. Linear calibration across wide concentration spans simplifies method development. Reduced spectral interference and absence of carry over enhance reliability in high alloy matrices. Manufacturers and laboratories can use this method for incoming material verification, in process control and final product testing to ensure material performance under corrosive or high temperature conditions.

Future Trends and Potential Applications

Advances may include integration of automated sample loaders, real time process monitoring, expanded elemental coverage and enhanced data analytics for predictive quality control. Miniaturization of glow discharge sources and coupling with remote sensing may extend use to field applications. Development of tailored reference materials will support analysis of emerging high performance alloys.

Conclusion

The glow discharge atomic emission spectrometer evaluated here delivers accurate, precise and efficient compositional analysis of stainless steels. Its linear response, low interference and high throughput make it a valuable tool for alloy producers, fabricators and quality control laboratories seeking to maintain specification compliance and control production costs.

Reference

Performance Note on stainless steel analysis using glow discharge atomic emission spectrometer model GDS500A, LECO Corporation, 2007.