Bulk Analysis of Boron in Low Alloy Steel (GDS900)

Significance of the Topic

Control of hardenability in low alloy steel is essential for producing high‐strength materials used in automotive, mining, petrochemical and construction applications. Boron, though required at very low concentrations, profoundly influences the final mechanical properties and can substitute for more expensive alloying elements. Accurate determination of boron alongside other alloying constituents is therefore critical to ensure consistent quality and performance in industrial production.

Objectives and Overview of the Study

This application note demonstrates a rapid, reliable bulk analysis method for measuring boron at trace levels (5–100 ppm) in low alloy steel using the LECO GDS900 glow discharge atomic emission spectrometer. Key goals include:

• Establishing a calibration curve for boron and common steel alloy elements.
• Assessing precision and accuracy at low boron concentrations.
• Evaluating throughput and drift correction strategies for routine use.

Methodology

Samples are prepared by grinding or polishing with zirconium oxide media (120–220 grit) to produce a flat, oxide‐free surface. The GDS900 employs a glow discharge source to sputter material uniformly from the sample. Excited atoms emit characteristic wavelengths that are detected by a CCD‐based spectrometer. Key features include minimal matrix interferences, linear response over a wide concentration range, and the ability to perform multiple analyses on the same spot without repositioning.

Instrumentation

• Instrument: LECO GDS900 Glow Discharge Atomic Emission Spectrometer
• Excitation: Direct current glow discharge plasma
• Detector: High‐resolution CCD array
• Sample handling: On‐axis mount for solid conductive materials
• Calibration materials: Certified Reference Materials (NIST, Brammer, CKD, MBH, IARM) and customer‐supplied standards

Main Results and Discussion

A linear calibration for boron from 5 to 100 ppm shows excellent correlation. Precision tests (ten replicates) at ~0.5 ppm B yield relative standard deviations of 6.7–7.0%. Major and minor alloying elements (Fe, Al, C, Cr, Mn, Ni, Mo, Si, Cu, etc.) exhibit RSD values typically below 2%. Two analysis modes were compared:

1. Single burn per spot: Total cycle ~70 s for three measurements.
2. Deep sputter mode (no sample repositioning): Ten analyses in ~160 s with comparable precision.

The results confirm the method’s robustness, rapid throughput and minimal drift when using homogeneous drift‐control standards.

Benefits and Practical Applications

The described approach enables:

• Simultaneous multi‐element quantification in steels.
• Low detection limits for boron critical to hardenability control.
• High‐throughput analysis (multiple burns in under three minutes).
• Reduced sample handling and traceability via certified standards.

Future Trends and Possible Applications

Advances may include integration of automated sample loaders, enhanced plasma control for even lower detection limits, expanded elemental libraries for novel alloys and coupling with real‐time process control systems. Data analytics and machine learning could further improve calibration stability and predictive maintenance in production quality laboratories.

Conclusion

The LECO GDS900 glow discharge spectrometer provides a rapid, precise and accurate method for trace boron analysis in low alloy steels, meeting the demands of industrial QA/QC with minimal spectral interferences, straightforward sample preparation and high throughput.

Reference

LECO Corporation. Bulk Analysis of Boron in Low Alloy Steel Application Note, Form No. 203-821-585, 2019.