Mechanisms of salt corrosion resistance alterations of refractory steels irradiated by intense pulsed electron beams

The objective of the present research is the discussion of test results, dedicated to the effect of intense pulsed electron beam irradiation regimes upon the corrosion resistance of refractory EP866sh and EP718ID steels under the thermo cycling conditions. The electron beam treatment was realized by means of the GESA-1 accelerator under the following conditions: electron energy - E=115-120 keV; pulse duration - τ=10-40 μs; and the energy density in a pulse (w) as well as the number of pulses (n) were increased from w=20 J/cm², n=1 up to w=36 J/cm², n=4. Some targets after irradiation were subjected to vacuum annealing for 6 hours at their service temperatures. Corrosion tests of initial and irradiated samples were performed under the following conditions: heating up to the operating temperatures, cooling in the seawater down to the room temperature. The target surface state prior to and after tests was studied by electron Auger spectroscopy, scanning electron microscopy and X-ray structural analysis. The test results showed that the corrosion resistance of samples, subjected to electron beam irradiation with the post-process vacuum annealing at the operating conditions, could be increased by 200-300 %.