Controlled Pattern

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.

Stamped Patterns

Ladder pattern

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.

Pyramid pattern

Machined Patterns

Small roses

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.