Fire-resistant structural steels

The resistance of buildings and other facilities to, fire depends on the extent to which their steel structures soften when heated to the temperatures created by the fire. A steel is generally considered fire-resistant if its strength where heated to such temperatures for short periods of time remains equal to 0.6-0.7 of its strength at room temperature. The alloying system Cr-Mo-V-Nb can be used for steels that are designed to be fire-resistant up to 700 degrees C. The greatest resistance to fire - up to 800 degrees C - is obtained in steels that contain boron.