Drew,
This opportunity for testing is awesome! I'm glad that Adam told you that composition testing would require a larger sample. That is what I fully expected and why I was suspicious of the metallurgical testing company that told me they could provide results from patterned damascus. I feel good about who you are working with.
It's very hard to do an accurate visual examination of the barrel metal through the photos. But, I keep looking at the grain structure of the steel along the broken edges. It appears to be of very large grain size. Large grain size in steel looks like sugar crystals. Small grain has a dull, gray appearance. If the grain is large, this would suggest that the steel was not thermal cycled enough and/or properly to reduce the grain size after forge welding. Large grain would not be terribly surprising. As I discussed in another thread, the barrel smiths knew that cold hammering improved the steel, but did not fully understand that it was the repeated heating and air cooling (thermal cycling) of the steel that caused a reduction in the grain size. The degree that the barrels were cold hammered, varied by the quality of the barrels. Too, the smith's skill at heating the barrels properly for grain reduction was surely a factor.
Large grain in the steel will weaken the steel slightly, but should not be considered a major defect or weakness. Though if embrittlement occurs, it would most likely begin in an area of large grain size, vs. small grain.
Photomicrograph examination will be very interesting. I think you may be amazed at how clean the steel is. I suspect that only a few very small slag inclusions will be found.
If composition testing of some demonstration rod material becomes a possibility, I might be bold enough to post up a prediction of what will be found. I'm fairly confident in what I believe to be the major alloys in the two materials. I haven't had time to do the research that I hope will help to determine the trace alloys. Let me know if you get some samples to test and I'll try to get my research done. I may end up looking like a fool, but I think it would be fun to see if my research is accurate.
