Volume I: Pattern-Welding
Pattern-welded steel, also known as mechanical damascus to differentiate it from crucible damascus, or “wootz” steel, is made by welding different layers of metal together and manipulating the resulting bar by folding and re-welding, punching, or twisting or other manipulation to give the end result of a blade with many contrasting layers when properly polished or etched. Sometimes the end result may appear as a series of stars, whirlpools or rungs on a ladder, sometimes it can appear very organic like a wood grain.
I usually start with 2 grades of high-carbon steel- 1084 tool steel and 15N20 or L6 nickel tool steel, to give higher contrast. All the steel I use in my pattern-welded stock heat-treat similarly and make excellent blades in their own right.
Layers of steel, each about 6" long, are ground clean to help ensure good forge-welding and tack-welded together, then a handle is welded on one end of what is called the “billet”. This is then placed into a hot forge- running 2200-2300 degrees F- and as it heats up a “flux” powder is sprinkled on the billet to melt and help prevent oxidation. When the billet is at the appropriate temperature- something learned through practice and often much trial and error- the billet is taken out and welded together by squeezing it between the dies of a press. After it is checked for soundness, the forge-welded stack is then drawn out to over double the length while maintaining the width. It can then be cut into sections, and re-stacked to bring up the layer count through further cycles.
One of the reasons for the cost of this material is the labour required and fuel to make good stock. Another is quite simply wastage of material. The successive welding and working heats can easily cause half the steel to end up on the shop floor as fire scale, and this before any blade shaping or grinding is done!