ABSTRACT
A dependency of susceptibility to brittle fracture identified experimentally on samples made of S355J2+N steel, representative for low-carbon unalloyed structural steel grades commonly used in construction, effectively cooled after surviving a simulated fire episode on the scenario of fire development followed is presented here. The conclusions are drawn based on the results of instrumented Charpy impact tests registered with automatic data gathering devices. It is shown, that the post-fire properties of the tested steel are determined not only by the level of temperature attained in it a priori, during the heating period, but also by the length of such period as well as by the cooling mode applied. Verification of the post-fire brittleness of structural steel seems to be the key in evaluation of its potential application possibility for extended service after surviving a fire incident. However, the obtained results turned out to be qualitatively different when referring to the future use of considered steel in summer conditions compared to those predicted for the same steel for winter conditions.
