Abstract: Based on the potential interfering elements specified in GB/T 4336—2016, T/CSTM 00010.2—2017 and ASTM E 415—08 standards, elemental interference effects were investigated in the determination of niobium content in high-grade non-oriented silicon steel. The results show that acid-soluble aluminum is identified as the major unconsidered interfering element affecting accurate measurement of niobium in high-grade non-oriented electrical steel. Combined with experimental tests and data analysis, an interference correction model is established for the niobium detection method. Comparative analysis and precision verification tests confirm the reliability and stability of the proposed model. The optimized analytical method integrated with the novel interference correction model enables the deviation between spectrometric determined values and chemical analysis results of niobium to be controlled within ±0.0002%, which fully satisfies the technical requirements of routine industrial inspection.

Key words: high-grade non-oriented silicon steel; niobium; acid-soluble aluminum; interfering element; direct-reading spectrometer