> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Charlie Bell > Sent: Thursday, June 29, 2006 12:56 AM > To: Killer Bs Discussion > Subject: Re: Physics Prof Finds Thermate in WTC Physical Samples > > > On 29/06/2006, at 4:06 AM, Dave Land wrote: > > Fuel that, when burning, generates less than 800 degrees C, about a > > third of the temperature needed to melt the steel used in the WTC. > > http://en.wikipedia.org/wiki/Image:Phase_diag_iron_carbon-color_temp.png > > You will see that iron undergoes a phase change at 600C, becoming > soft and pliable. It is this phase change that allows farriers and > swordsmiths to shape iron in a controlled manner. Steel changes from > the solid metal it is at room temperature, to a material with a > consistency and structural integrity about the same as well-chewed gum.
Good find on the phase diagram Charlie. To pick a nit, if the consistency and structural integrity at that temp was actually the same as well-chewed gum, I don't think that blacksmiths would have required big hammers and big arms. :-) Hyperbola aside, I presume that you have no difficulty with the multiple references to about a factor of 2 reduction in yield strength at that temperature. Dan M. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
