The blacksmiths at Colonial Williamsburg have taken advantage of a  
brick kiln to run some cementation experiments. They have put  
sandstone coffins filled with powdered charcoal and bar iron into the  
brick kiln and left them in for the burn. They have gotten some  
results that are not what I understand is the norm for cementation.

It is my understanding, from reading, that the reason the British  
used cementation, rather than fining pig to steel (which was done in  
Europe for a while and continued to be done in Germany), was that it  
was much easier to control. Thus the British took pig iron and  
decarburized in through fining and then recarburized in in the  
cememtation furnace. The sources I remember reading, stated that  
cementation resulted in a maximum of about 1.5%C. And that regardless  
of how long you left bar iron in a cementation furnace that the  
penetration of C was not very deep. I am looking at a 1/2" bar of  
cast iron. At least the fracture sure looks like cast iron. The  
people at Williamsburg told me that they have 1x2.5" bars that appear  
to have almost completely carburized. It does produce a good spark  
with flint. They do not have a means to test the carbon content.  
anyone want to volunteer?