Surface modification of heat-resistant 12Cr1MoV steel carried out with the use of highintensity Zr ion beam has been conducted. It was revealed that the treatment gives rise to the formation of the softened modified surface layer. The effect of Zr ion beam irradiation onto impact toughness at ambient, increased and high temperatures of 20°C, 375°C and 600°C, and as well as analysis of loading diagrams ”load vs. deflection” has been carried out. The analysis and discussion of the obtained results have been performed
