Standard Test Method for Optical Emission Vacuum Spectrometric Analysis of Blast Furnace Iron by the Point-to-Plane Technique

This test method describes the optical emission vacuum spectrometric procedure for examining blast furnace iron (hot metal) containing 4.2 to 5.0 % carbon by the point-to-plane technique. This spectrochemical technique is intended specifically for the analysis of silicon, manganese, phosphorus, titanium, and sulfur in specified concentration ranges in blast furnace iron. Apparatus needed for this procedure shall include sample mold, grinder, supporting electrode, excitation source, spectrometer, and appropriate measuring system. The sample is excited in an inert gas atmosphere by a controlled triggered capacitor discharge using the point-to-plane technique. Using a vacuum spectrometer, the radiant energies of selected analytical lines and an internal standard line are measured by photomultipliers. The output current of each photomultiplier is accumulated and stored during the exposure period as a charge on an associated capacitor, where it appears as a measurable voltage. At the end of the exposure period the voltages corresponding to the analytical lines relative to the voltage for the internal standard line are measured. The measuring system may be calibrated in terms of percent concentration.