[en] To estimate the influence of various types of multiple thermal cycles on the microstructure and mechanical properties of the 13HMF steel, investigations have been performed by using the thermal and stress cycle simulator and by taking advantage of the design of experiments. Specimens were heated to maximum temperatures in the range of 600-1200 ^oC, different soaking times at those temperatures were applied and cooling times t_8/5 to room temperature. During the tests specimens were free to deform, as well as loaded by a tensile force. Microstructures of simulated heat affected zones (HAZ) have been investigated, Vickers hardness HV10, Charpy V notch toughness and mechanical properties (R_e, R_m, A₅) were determined. Results are presented in the form of equations and graphs, which show relations between the parameters of thermal cycles and the individual properties of simulated HAZ's. (author)