Chuck, I agree with youabout today's metals. I think the definitions you gave would equally apply to a situation of unequal carbon content of plain carbon steel made as described above. The case on the rods would be of higher carbon content than the core. Unless literally melted, this difference in carbon content would be retained during the forging process. So, what we are seeing is sort of a steel-steel damascus of very simple pattern. Had the rods been twisted and rolled out per pattern welded barrels we would see a much more complex pattern of these lines.

DDA