By pattern-controlling layered steel, the different types of
Damascene steel are generated. The pattern types can be divided into two groups,
layered pattern and twisted pattern. The layered patterns again are
subdivided into the die-stamped and machined patterns, as illustrated in the following.
After bringing the layered steel to
forging-temperature a die is driven into the surface. The
layers are not completely planar any more, so some are cut
when the surface is ground flat. This grinding exposes some of the
inner layers, revealing the pattern related to the die. The pattern
is most pronounced close to the surface. If the blade is forged
close to the final shape, the pattern will be more distinct than when
grinding the blade out of a Damascene bar.
How deep the pattern-control reaches into the steel-bar
depends on the type and coarseness of the dies. Patterns from
a engaging die –the elevations of the upper and lower die
alternate in position– normally run through the whole
package; the middle layers are less strongly deformed.
Non-engaging dies, like the big-rose pattern, cause a
more superficial pattern.
Cut patterns are generated by mechanically removing material
from the layered steel. This can be done by milling, drilling,
planing, or grinding. After machining, the steel-bar is forged
flat. The further treatment is then equal to the stamped
patterns. In most cases it is difficult to distinguish between
a stamped and a machined pattern without making a microsection.
Typical representatives of controlled patterns are
big- and small roses, pyramids and the ladder. Other
patterns try to imitate twisted patterns, such as the
false twist or the stamped star.
© 2005 G.v.Tardy