I believe that the perceived crystalline pattern that you can see is very likely the result of "cold forging", in reality the material is not cold when it is hammered, it has gone into the black heat range, and a bladesmith will sometimes continue his hammering into this heat range because it is believed --- & is possibly true --- that this "cold forging" will result in a higher degree of compacted material and a harder blade.
From experience I can say that if a mild steel, say below .5% carbon, has been used to make the blade, this "cold hammering" does work, because we do not draw a low carbon steel, we only quench at critical heat --- ie, where the material loses its magnetic properties.
If cold forging were to be used with a high carbon steel, this would really be counter intuitive & counter productive, because the correct heat treat cannot be improved upon.
|