Gaffney's monkey with another simplistic analysis.
Here, read the facts.
An Initial Microstructural Analysis of A36 Steel from WTC Building 7
Rapid deterioration of the steel was a result of heating with oxidation in combination with intergranular melting due to the presence of sulfur. The formation of the eutectic mixture of iron oxide and iron sulfide lowers the temperature at which liquid can form in this steel. This strongly suggests that the temperatures in this region of the steel beam approached ~1,000ºC, forming the eutectic liquid by a process similar to making a “blacksmith’s weld” in a hand forge.