[en] Numerical analysis of changes of X-ray diffraction pattern in chromium steels after ionic irradiation was conducted. Samples of Kh12MFB steel of ferrite-martensite type, subjected to standard heat treatment (normalizing at 1050 deg and tempering at 720 deg C) with successive aging at 500 deg C during 1.5 H, were irradiated by 40 keV Ar ions up to doses of 10¹⁷-3.10¹⁸ ion/cm² at 500 deg C. Analysis of diffraction effects, accompanying radiation-induced lamination in alloys of iron-chromium system, as well as of changes, taking place during annealing shows that the role of irradiation is not reduced to transformation stimulation in solid solution, usually observed under thermal holdings