Bulk Analysis of Low Alloy, Cr-Mo, Free Machining, and Austenitic High Mn Steels

Significance of the Topic

Chemical identification of steel alloys by elemental composition is essential to ensure product performance, machinability, and corrosion resistance across industries. Bulk analysis provides definitive classification where mechanical tests alone are insufficient.

Study Objectives and Overview

This application note evaluates the analytical capability of the LECO GDS900 glow discharge atomic emission spectrometer for rapid, routine determination of alloying elements in low-alloy, Cr-Mo, free machining, and high-Mn austenitic steels. The goal is to demonstrate accuracy, precision, and throughput.

Applied Methodology and Instrumentation

The GDS900 employs a glow discharge plasma to sputter material uniformly from conductive sample surfaces, reducing matrix history effects. Neutral atomic emission lines dominate the spectra, minimizing interferences and ensuring linear response over wide concentration ranges. Sample preparation used a 120-grit zirconium oxide belt or disc via LECO BG grinder or LECO PX polisher. Calibration curves were generated with Certified Reference Materials (CRMs) and Reference Materials (RMs) from BAS, Brammer, ARMI, CKD, and NIST, with drift correction by homogeneous set-up standards. The software’s “analyze all in one spot” mode enabled three sequential burns within 90 seconds without dropping the sample.

Used Instrumentation

• LECO GDS900 atomic emission spectrometer with CCD-based detection
• LECO BG belt grinder and LECO PX polisher for surface preparation
• Certified Reference Materials from BAS, Brammer, ARMI, CKD, NIST

Key Results and Discussion

Analyses of a NIST low-alloy steel standard, Cr-Mo grade F9, free machining 12L14, and high-Mn austenitic steel demonstrated linear calibration up to over 8% Cr, with RSD values below 1% for major constituents and below 4% for trace elements. Reproducibility across three burns confirmed negligible contamination and consistent sputter removal, highlighting the technique’s robustness.

Benefits and Practical Applications

• Rapid alloy identification and quality assurance in steel manufacturing
• High throughput: multiple analyses per minute
• Wide linear range from trace to high-percent elements
• Low spectral interference and stable calibration

Future Trends and Potential Uses

Integration with real-time process control systems for continuous monitoring
Development of AI-driven data analysis for automated alloy classification
Expansion to novel alloys, coatings, and additive manufacturing feedstocks
Portable or remote GDS systems for field-based materials verification

Conclusion

The LECO GDS900 delivers fast, accurate, and reproducible elemental analysis of diverse steel grades, supporting stringent industrial QA/QC requirements and enabling optimized alloy design.

References

• LECO Corporation, Application Note “Bulk Analysis of Low Alloy, Cr-Mo, Free Machining, and Austenitic High Mn Steels”, Form No. 203-821-573, August 2019