METHOD FOR DETERMINING SULFIDE IN STEEL CONTAINING MO AND NB BY MEANS OF X-RAY MICROANALYZER

摘要

PURPOSE:To accurately determine sulfides in a steel, by measuring a steel containing Mo or Nb by means of an X-ray microanalyzer and then by analyzing the measured values by compensating the influences of Mo and Nb on the X-ray intensity of S. CONSTITUTION:A steel containing either or both of Mo and Nb is measured by an X-ray microanalyzer with regard to many picture elements of S, and, from the obtained measured values of X-rays, sulfides are qualified and determined. In the above-mentioned method for determining sulfides, the parts where the X-ray intensity of S is higher than XS [where XS means the value of X-ray intensity (cps) for qualifying sulfides] represented by an equation XS=BG0+ AXMo+BXNb+5(BG0+AXMo+BXNb)0.5, where BG0 means the background value of S(cps) when the amounts of Mo and Nb are 0wt.%, respectively, and A and B mean the incremental values of the background values of S when the amounts of Mo and Nb are 1%, respectively, are qualified as sulfides. By this method, the influences of the concentrations of Mo and Nb close in wavelength are compensated, and the sulfides can be accurately qualified and determined.