The method of processing information about nonmetallic inclusions obtained from the investigation of the surface of finished steel samples

Nonmetallic inclusions formed in the process of steel production are microparticles of chemical reactions products and foreign impurities having dimensions of 0.1–100 microns. They concentrate stresses in finished products and impair the mechanical properties of steel. To study them, sections are made from the sample of the tested metal and microscopic sections of inclusions are observed in the microscope. However, on the section plane a researcher does not see the inclusions themselves, but only their sections, while inclusions of different sizes can give the sections of the same size and, conversely, the inclusions of the same size can produce the sections of various sizes. In this paper, we consider a method for determining the amounts and sizes of nonmetallic inclusions on the basis of this information, that is, reconstructing the volume picture of the inclusion size distribution based on еру plane distribution of their sections by a section plane. The method is based on probability theory and mathematical statistics. It is shown that the number of inclusion sections into each size interval obeys the normal law. A technique for determining the distribution function of inclusions with respect to sizes for inclusions of a spherical shape and an appropriate algorithm has been developed.