Carbon and Sulfur Determination in High Carbon Ferroalloys (CS844)

Importance of the Topic

Reliable determination of carbon and sulfur in high-carbon ferroalloys is essential for maintaining steel quality and performance. Accurate measurement of these elements in alloy feedstocks ensures that final steel and cast iron products meet strict mechanical and corrosion-resistance specifications.

Objectives and Overview

This study describes a combustion-based analytical method using the CS844 instrument for simultaneous carbon and sulfur analysis in ferroalloys. The aim is to establish a robust procedure with high precision, low detection limits, and efficient throughput for routine quality control.

Methodology and Instrumentation

The core analysis employs high-temperature induction furnace combustion. Samples are mixed with iron powder, vanadium pentoxide, and LECOCEL accelerators. Key parameters include a 100% furnace power, constant furnace mode, and purge and delay times optimized for complete combustion. Instrument blanks, calibrations, and drift corrections are performed using LECO certified and NIST reference materials. The primary instrument is the LECO CS844 carbon/sulfur analyzer.

Key Results and Discussion

Typical results for ferromanganese showed average carbon of 6.892% (standard deviation 0.012%) and sulfur of 0.0014% (s = 0.0001%). Ferrochromium samples yielded 4.190% carbon (s = 0.043%) and 0.0675% sulfur (s = 0.0008%). Calibration curves forced through the origin demonstrated linear response across the concentration range when using high-carbon ferroalloy reference materials. Blanks were consistent and effectively subtracted, despite relatively high carbon blank levels.

Benefits and Practical Applications

• High precision and repeatability for quality control in steel and cast iron production
• Fast analysis cycle supporting high laboratory throughput
• Reliable simultaneous measurement of carbon and sulfur with minimal sample preparation

Future Trends and Opportunities

Advancements may include further automation of sample loading, integration of real-time data analytics, and development of furnace designs to lower detection limits. Emerging accelerator chemistries could enhance recovery of trace sulfur. Coupling with online process monitoring will enable tighter process control.

Conclusion

The described method provides a robust, precise, and efficient approach for carbon and sulfur determination in high-carbon ferroalloys using the LECO CS844 analyzer. It supports critical quality-control workflows in steel manufacturing.

References

• LECO Corporation. Carbon and Sulfur Determination in High Carbon Ferroalloys, Application Note, Form No. 203-821-602, 2019.