Accurate and fast elemental analysis is a critical requirement during the production of steel. It is not only required for compliance with quality standards, but it also enables the steel producer to save costs in an increasingly competitive environment.
To address the needs of the steel making industry, with regard to speed and flexibility in analysis, Zetium sequential XRF systems can be delivered precalibrated with a low alloy steel (LAS) package. The pre-calibrated solution is based on more than 90 certified reference materials (CRMs) and four monitor samples for drift- and sample preparation correction.
Accurate and fast elemental analysis is a critical requirement during the production of steel, from raw material control to the final product quality. It is not only required for compliance to quality standards, but it also enables the steel producer to save costs in an increasingly competitive environment. Axios FAST is ideally suited for many applications where speed and accuracy are key factors.
This data sheet demonstrates the performance of Axios FAST XRF simultaneous spectrometer for the analysis of low alloy steel.
Axios FAST is a fully integrated simultaneous wavelength dispersive XRF spectrometer, complete with X-Y sample handler and state-of-the-art software. It is engineered for excellence in terms of both analytical and operational performance.
X-ray tube: Rhodium anode 4 kW SST-mAX tube
Tube power: 60 kV/ 66 mA
Fixed channels: C, Si, P, S, V, Cr, Mn, Fe, Ni, Cu, Mo Medium: Vacuum
Shielding plate: 27 mm Rh plated
Sample holder: Stainless steel 27 mm aperture Flow counter window: 0.6 μm for carbon analysis
10 standards (SS 401/1 – SS 410/1) were used to set up the calibration. The standards were freshly surfaced prior to measurement with a Herzog grinding machine using 150 grit Al2O3 sandpaper. The X-ray intensities of 10 elements were measured simultaneously for 10 seconds at the peak. The calibration was performed using the Fundamental Parameters (FP) regression model incorporated in the SuperQ software package during calibration. Line overlap corrections were automatically determined through multiple regression by the software. No other corrections were applied.
The analysis speed is usually limited by the element with the lowest sensitivity (carbon in this case) and/or the lowest concentration. With the Axios FAST excellent results are obtained for all elements, including carbon. Figures 1 and 2 show the calibration graphs for C and Ni.
Figure 1. Calibration graph for carbon
Figure 2. Calibration graph for nickel
Table 1 gives an overview of the elements with their concentration range, their respective values for the ‘root mean square’ (RMS) error, K factor and the lower limit of detection (LLD) based on a 100 seconds counting time. RMS (absolute error) and K (relative error) represent the accuracies of the calibration. The K factor is a weighted residual error and is a measure of the differences between the measured concentration and the supplied, certified chemical concentration. As a general rule, K factors < 0.05 indicate accurate calibrations. Using the K factor it is possible to estimate the accuracy of a result, accounting for both instrumental error and errors associated with the certified concentrations of the reference materials defining the calibration.
The precision, repeatability and reproducibility of the Axios FAST is outstanding, not only for short-term measurements (20 consecutive measurements), but also for longer-term measurements (measurements carried out over a period of 10 days), see Table 2 and Figure 3. For comparison, the counting statistical error (CSE) expressed in concentration units is also shown in Table 2. The CSE is the theoretical minimum possible error and the data demonstrate the inherent stability of the Axios FAST instruments. The sample was freshly surfaced before each measurement. No drift correction was applied.
Table 1. Values for ‘root mean square’ (RMS), K factor, and lower limits of detection (LLD)
Table 2. Analytical precision (measured on SS 410/1)
Figure 3. Short- and long-term stability measurements of C and Si in SS 410/1 low alloy steel standard
Axios FAST is capable of analyzing low alloy steel precisely and accurately. A total measurement time of only 10 seconds is required to analyze 10 elements, including carbon.