Analysis of Low Alloy, Cr-Mo, 12L14 and Hadfield Steels

Significance of the topic

Accurate classification of steels by chemical composition is essential for quality control in manufacturing, compliance with industry standards, and ensuring material properties meet design requirements. Glow discharge atomic emission spectrometry (GDS) provides rapid, routine quantification of major, minor and trace elements in ferrous alloys, overcoming limitations of destructive microanalysis and surface contamination.

Objectives and overview of the study

This application note evaluates the performance of the LECO GDS500A instrument for determining elemental composition in a range of steel alloys (low-alloy Cr-Mo steel, 12L14, Hadfield steel, AISI 94B17). Key goals include demonstrating:

• Accuracy and precision against certified reference materials.
• Linearity of calibration curves across a broad concentration range.
• Speed and repeatability of multi-spot analyses without repositioning samples.

Methodology and instrumentation

The GDS500A employs a glow discharge source with CCD-based optical detection. Sample surfaces are prepared using zirconia-oxide abrasives to expose fresh metal. Calibration uses certified reference materials from NIST, ARMI, BAS and Brammer, with factory-installed steel calibrations tailored to customer requirements. Drift is corrected via homogeneous setup standards.

• Sample prep: 120-grit zirconium oxide belt or disc.
• Instrument: LECO GDS500A glow discharge atomic emission spectrometer with CCD detector.
• Calibration: Linear working curves covering trace to percent levels; extended linearity up to 1.5× highest standard.
• Analysis mode: Multi-burn “analyze all in one spot” allows three sequential measurements in under 90 seconds.

Main results and discussion

Analyses of NIST and IARM reference steels demonstrate high accuracy (relative errors typically below 5 %) and excellent precision (RSD generally below 2 %). Key observations include:

• Low‐alloy Cr-Mo steel (NIST 1762): Major alloying elements (Cr, Mn, Mo) within 2 % of certified values; RSD <1 %.
• 12L14 steel (IARM 183A): Trace carbon and phosphorus accurate to better than 1 %; lead quantification shows <7 % relative error.
• Hadfield steel (Brammer BS17): High-manganese content measured with <0.3 % RSD; minor elements quantified reliably.
• AISI 94B17 (NIST 1262B): Multi-run reproducibility across ten burns delivers RSD below 4 % for all elements from Al, B, C to Zr.

Benefits and practical applications

GDS analysis offers:

• Fast turnaround: Three analyses in 70–90 seconds without sample repositioning.
• Minimal matrix effects: Sputtering removes surface oxides and coatings, reducing spectral interferences.
• Broad dynamic range: Single calibration curves span trace ppm to high‐percent concentrations.
• Routine production suitability: Stable CCD optics and drift correction enable unattended operation in QA/QC labs.

Future trends and opportunities

Advances in detector sensitivity and data processing will further lower detection limits and enhance multivariate correction of spectral overlaps. Integration with automated sample handling and digital quality management systems will streamline high-throughput alloy classification. Expanding calibrations for emerging high-performance steels and additive-manufactured alloys will broaden GDS applications.

Conclusion

The LECO GDS500A demonstrates robust performance for routine elemental analysis of steels, delivering accurate, precise and rapid results across a wide range of alloy types. Its ease of use and flexible calibration options make it a valuable tool for industrial metallurgical laboratories and QA/QC environments.

Reference

1. LECO Corporation. Spectroscopy Performance Note: Analysis of Low Alloy, Cr-Mo, 12L14 and Hadfield Steels. Form No. 209-076-025, 2007.