Citat:
Ursprungligen postat av Malmoesoldier
SLOB. Nej dom hitta bara 250C, finns inga andra uppgifter. dom säger att dom inte hitta några temperaturer som möte 600C som hade börjat göra de lite svagt, och att dom bara hitta 250C på tre ställen och allt annat var under 250c. det är faktan.
Jag orkar inte sitta och skriva av hela stycken ur NIST, eftersom det inte går att kopiera, så jag nöjer mig med meningarna runt:
Citat:
s. 231 NISTNCSTAR 1-3C
Single Column K-16
(...)
While analysis of sample K-16 yielded no revelations on the collapse mechanism for the buildings the changes in web material as a result of high temperature corrosion exposure were interesting.
(...)
The spheroidization was most likely a result of extended exposure of the steel in this region to temperatures just below the lower critical temperature (A1. ~727ºc).
(...)
Assuming that the original microstructure in this area was similar to that found in fig. 6-22a, the re-distribution of pearlite and larger ferrite grain size would imply significant changes in the microstructure that could only been achieved through austenitizing of the steel. Concomitantely, this would suggest that temperatures were much higher in this portion of the plate than found at the base of the column. With the average weight percent carbon in the material at 0.16, the plate temperature would have to exceed 830ºc (above the upper critical temperature [A3])
(...)
Instead, it appears that at some point in this sample's history, it reached a relatively high temperature (above the A3 line) (...)
Floor truss sample C-115
Two facts have led to the conclusion that this floor truss rod was heated above the A3 line (...)
Single Column K-16
(...)
While analysis of sample K-16 yielded no revelations on the collapse mechanism for the buildings the changes in web material as a result of high temperature corrosion exposure were interesting.
(...)
The spheroidization was most likely a result of extended exposure of the steel in this region to temperatures just below the lower critical temperature (A1. ~727ºc).
(...)
Assuming that the original microstructure in this area was similar to that found in fig. 6-22a, the re-distribution of pearlite and larger ferrite grain size would imply significant changes in the microstructure that could only been achieved through austenitizing of the steel. Concomitantely, this would suggest that temperatures were much higher in this portion of the plate than found at the base of the column. With the average weight percent carbon in the material at 0.16, the plate temperature would have to exceed 830ºc (above the upper critical temperature [A3])
(...)
Instead, it appears that at some point in this sample's history, it reached a relatively high temperature (above the A3 line) (...)
Floor truss sample C-115
Two facts have led to the conclusion that this floor truss rod was heated above the A3 line (...)
Därmed lägger jag nog ner temperaturjagandet - eftersom jag inte fått förklarat för mig ännu vad det har för relevans.
/S
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