WOOTZ or SHAM?

[Jeff Pringle]

I'd expect that a "wootzy" blade with lower carbon content than high-carbon wootz which properties don't stand above regular steel blades would be considered inferior by people who actually used these weapons (and whose survival might have depended on any little advantage). Is there anything along these lines hinted at in the historical sources?

From “Persian Steel, the Tanavoli Collection” by Allan & Gilmour, quoting a French traveler to Iran in the 19th Century:
“…A watered steel sword of the finest quality is priced at 2,400 Francs, of good quality at 240, and of ordinary quality at 36, whilst the figures for an ordinary steel sword are 60, 18 and 6 Francs…”

That does not really help, we don’t know if he was referring to wootz or PW, or what the quality designations were. But I would expect the HC wootz would fetch the most, with LC wootz and/or extra-nice PW next in line and $ heading downhill from there – I’ll look for better references. But it does show that they recognized one type of watered steel as being ten to forty times better than everything else, which is tantalizing.

Perhaps the term “mechanical damascus” does not bear the same implication of intent (as pattern welding), but it is not in as widespread use, so to avoid confusion I can live with PW.
EDIT - The term comes from (as far as I know): the steel has a pattern, the pattern is from welding. It was created to differentiate PW from crucible-origin steels. There's something about this in "Persian Steel" too - it's a book with a lot of info!
Historically the process of folding a steel repeatedly was used to refine non-homogenous material, and pattern welding grew out of that – combine different materials with the same technique to create effects which also prove quality and show off skill. The blade does not necessarily gain from the process, but usually one combines steels that are tough and steels that are hard to get both properties in the blade. How much of that is real, and how much superstition, is currently a subject of debate in bladesmithing circles.

I’d lump the Japanese blade tradition into pattern welding too, because when you weld steel to itself you get a pattern due to the weld zone being slightly decarburized in the process. And the smiths control the pattern very specifically, to achieve different grain (itame, mokume, masame hada) in the finished sword. In the Edo period, when flashier stuff was in fashion, they even filed/hammered the material in the same manner as Persian and Indian smiths to get more obvious grain (ayasuga hada). We don’t think of them as pattern welded because the material is not treated in a way to make the patterning stand out.
The starting material for the Japanese steel was iron oxide sand, but once it went through the smelter it became a lump of steel, slag and charcoal fire residue, much like a bloom from European smelters but they were shooting for higher overall carbon in the Eastern method. So the folding was to squeeze out impurities and level out the carbon content.