VALIDATION OF METHODS FOR WDXRF AND OES-SPARK TECHNIQUES IN STEEL ANALYSIS. DETERMINATION OF THE UNCERTAINTY OF MEASUREMENTS FOR API STEEL PLANT SAMPLE / Validação de métodos para as técnicas de WDXRF e OES -spark, na análise de aços. Cálculo de incerteza de medição para amostras de processo, aço classe API

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The increase of gas and petroleum demanding in the national and international markets, the specification and certification of the chemical analysis results of gas and oil pipe-line have became more and more challenging. A continuous development has been outlined to improve API grade alloy steels (American Petroleum Institute). The steel properties depend on the chemical composition control and process parameters during its manufacturing. In this work, a comparison of the measurement uncertainty between X-ray fluorescence (WD system) and Optical Emission (OES-spark) spectrometries, for API grade steel plant samples analysis, was outlined. Usually, this kind of analyze requires less than 40 seconds for full chemical characterization for adjustment in the process parameters production. The main influence source in the chemical analysis was evaluated for design of experiments. The constituents and trace elements such as Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, As, Nb, Mo and Sn were determined using the ASTM E-322, E-415, E-1009 and E-1085 standard methodologies. The 185A and 187A certified reference materials from CMI (Czech Metrology Institute) were used for evaluation of the methods. The uncertainty of the measurement, precision, accuracy, repeatability and reproducibility of the measurements were obtained applying statistic tests, recommended by ISO/IEC 17025. The uncertainty of measurement for each element is discussed for both techniques.

ASSUNTO(S)

fluorescência de raios x incerteza de medição validação incerteza de medição emissão óptica emissão óptica fluorescência de raios x validação

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