Our present study is aimed at increasing the operational durability of massive two-layer mill rolls with a working layer of white chrome cast iron (15.9–16.4%Cr) by decreasing the retained austenite fraction. The latter is achieved by additional alloying with molybdenum and tungsten, as well as by applying cyclic annealing with double heating at subcritical temperatures (450 or 550 ℃, depending on the chemical composition of studied cast iron). The scientific novelty includes establishing the differing influence of molybdenum or tungsten alloying on the properties of the studied alloys. Via the fractal analysis of the microstructure it is discovered that the microhardness level is sensitive to the fractal dimension of the structural components. The difference in microhardness value is especially noticeable in a metal matrix: its levels are 1.5 times higher if the matrix is only alloyed with Mo. Such difference is associated with an increase in the fraction of ferritic component due to precipitation hardening which happens in the as-cast condition in alloys containing W. The practical value of our study lies in decrease of the residual austenite fraction, and, accordingly, in the reduction of tendency to cracking during the operation of products which is possible due to both dispersion hardening in the process of additional alloying with carbide-forming elements and cyclic annealing. The obtained results confirm possibility of using the fractal dimension to assess the microhardness of precipitation hardening products in cases when measuring via standard methods is difficult due to the small size of the objects of study.