WTC 7 Follow up Metallurgical Report

[LARED]

http://www.springerlink.com/content/g5w603461r3078t3/?p=fcff0480a20b42f0b97f05f0d59ed59f&pi=2

Introduction
The Worcester Polytechnic Institute Materials Science and Engineering faculty was asked by the Federal Emergency Management Agency (FEMA)forensic team to examine the microstructures of the steels from the World Trade Center disaster to determine the maximum exposure temperatures and to identify the mechanism for the extensive metal removal. These determinations were based on microstructural examination of portions of a beam. ........

Preliminary results from this investigation were presented in 2001<1> and the FEMA report,<2> and this case history updates those reports.

.................. (Lots of Technical stuff)

Discussion

Based on these metallurgical observations, canthe temperature, time, and environment that this beam was exposed to be determined?
The microstructural changes in the steel must have occurred at temperatures between 550 and 850 °C. These changes would require times on the order of hours.

The microstructure of the slag with the eutectic structure and the primary FeO indicates temperatures in this region above 940 °C and
maybe up to 1100 °C, as indicated by the phase diagram.<4>

The metal removal rates from A36 steel by this liquid slag are not known and may be highly dependent on impurity content as well as oxygen and sulfur partial pressures in the atmosphere of the fire. However, preliminary experiments<5> at 1100 °C with mixtures of FeS and FeO placed on the steel surface and heated in air indicated that the reaction was not fast and dissolved little metal in 24 h.

This observation indicates that the liquid slag attack probably took place during the prolonged exposure to the fire in the rubble.
Another frequently asked question concerns the source of the sulfur. Some of the sulfur may have come from the fuel on the airplanes or the fuel that was stored in Building 7. However, this source would have been short-lived in the fires. Sulfuric acid in acid rain or SO2 or SO3 in the atmosphere could also contribute sulfur to the slag. A more probable source of sulfur is the materials in the building, such as gypsum (hydrated calcium sulfate) board or other construction materials.

Conclusions

The maximum temperatures in the beam from Building 7 varied with position along the beam, and the maximum local temperatures were above 940 °C. The extensive metal removal from the beam occurred by the reaction between a liquid iron oxide and iron sulfide slag and the steel. The oxides and sulfides formed by a reaction between the steel and the environment in the fire at high temperatures.

The metal removal most probably occurred in the fire in the rubble after the building collapsed rather than during the fire while the building was standing. The source of the sulfur was most probably the materials of construction in the building (e.g., gypsum ]board) rather than the sulfuric acid in acid rain or the jet fuel.

[Bolo Boffin]

1. Good stuff. Thanks, LARED. n/t

[LARED]

2. You're welcome

I'm so shocked there are no CT'ers jumping to discredit the report :sarcasm:

[Ohio Joe]

3. Worcester Polytechnic...

I lived and worked in Worcester MA for about 10 years before I moved to OH. Everything I've heard tells me it is a good school.

[mhatrw]

4. So what is this supposed to prove or disprove?

Help me here, LARED.

[LARED]

5. Just a few things

The steel did not vaporize

There were no "thermite signatures"

The steel was subject to high temperatures for an extended time.

There's more, but it is a waste of my time to highlight them, as you're a CT'er and no amount of evidence of logic will sway you away from your fantasy.

[mhatrw]

6. The steel was subject to high temperatures for an extended time in the rubble pile.

Who ever said WTC-7 steel vaporized?

Where did this report say there were no thermite signatures?

[SDuderstadt]

7. "Where did this report say there were no thermite signatures?"

Typical truther question. One could assume from the lack of any mention of thermite signatures that the report is establishing there weren't any. This is so elementary.

[mhatrw]

8. One could also assume that one will not find what one does not look for.

This is so elementary.

[SDuderstadt]

9. Jesus, mhatrw

if there's evidence of thermite, then please provide it. Don't blame NIST for the "truth movement's" failure to prove their case.

[anigbrowl]

10. No, one could not.

If this were true, one could never be surprised since one wouldn't see unexpected things.

Metallurgists are in the business of knowing the physical and chemical structure of metals. I think they're capable of spotting incongruities which would leave forensic traces. You might as well argue that that they failed to rule out the possibility of Santa Claus being involved, so therefore it's a real issue.