Could the sulfur in the drywall combine with fires to lower the melting point of steel in a eutectic reaction? In other words, is there a mechanism that could involve the sulfur present in the gypsum wallboard in intergranular melting of steel? Would that be hot enough to evaporate steel, or just melt it, or neither?
What's going on here?
http://911research.wtc7.net/wtc/evidence/metallurgy/WTC_apndxC.htm
The original form of the document you linked is
here. I've addressed this several times already, including the last thread where you brought this up. You can read
in this post why the findings rule out thermate.
However, your question is a reasonable one.
It is not fully understood how the sulphur bound to the iron in this mixture. These pieces of steel were singled out because they are unusual, and also quite rare among the rubble where they were found.
The fact that the sulphur led to a eutectic mixture does not mean that the steel was melted or evaporated. Far from it, in fact. Because the mixture
is eutectic, but is still there rather than melting (breaking the molecular structure observed and changing the shape of the steel pieces), it says that the steel was not only never melted, but it never experienced temperatures that would melt the eutectic mixture, found to be much lower than the normal melting point of steel. So the answer is "neither." However the sulphur got there, it must have happened well below the steel melting point.
The sulphur got there not because of melting, but through some other chemical process. It probably did involve heating, however, although it's barely possible that exposure at room temperature at a very long time could lead to the effect seen. The more likely hypothesis is that sulphur was present while the steel was exposed to elevated temperatures, but temperatures well below its melting point and below the melting point of the mixture.
One possible culprit, since the pieces came from WTC 7, is the large amount of diesel fuel contained in the structure -- which burned. My best guess (which could easily be wrong) is the sulphur in the samples seen came from the diesel fuel, while it was burning. But I suppose it is also possible that crumbled wallboard was the source of the sulphur, perhaps sprinkled on or held in close proximity to the steel as the fires raged around it. Hard to be certain.
While these samples are interesting, I have seen no speculation that they were anything but point oddities, and thus did not contribute in any meaningful way to WTC 7 collapse. These samples also rule out thermate, as explained in my other post. Thus, they are interesting and worthy of study, but ultimately do not contradict the official theory in any way.