Liquid steel analysis with laser-induced breakdown spectrometry in the vacuum ultraviolet

Laser-induced breakdown spectrometry (LIBS) with multiple pulse excitation has been applied for the multielemental analysis of liquid steel. The laser beam and the measuring radiation are guided inside a moveable lance to gain access to the melt surface from the top. Low-alloy steel grades were investigated with a focus on the light elements phosphorus, sulfur, and carbon by use of emission wavelengths in the vacuum ultraviolet. Calibration curves were determined for the elements carbon, phosphorus, sulfur, nickel, and chromium in steel melts of 100 kg. The estimated limits of detection for the light elements phosphorus, sulfur, and carbon are below 21 µg/g for direct analysis of liquid steel with LIBS. The results demonstrate the potential of the laser-based analysis to fulfill the requirements for a process integrated on-line analysis in the secondary metallurgy of steel works.