Origin of Damascus steel
Damascus steel (also known as Wootz steel) is a steel material made in ancient India. Steelmaking has a long history in India. The Indian craftsman could produce excellent steel far before BC. The existing “Delhi’s Iron Pillar”, made from Damascus steel, has not rusted even in the present age of more than 1600 years. Damascus steel is proved to be an excellent steel material.
Mystery of Damascus steel
The mystery of Damascus steel comes from its toughness, rust resistance, and graceful ripple patterns floating on the surface. The manufacturing method is another mystery as well for it has not been handed down to the present day by male-child-only hereditary.
In the early modern period, Damascus steel was prized as a cherished material for cutting tools, and it was handed down as a royal heirloom during the Crusades due to its sharpness. The Damascus steel gained fame as a symbol of status.
Modern stainless steel was developed while studying the manufacturing method of Damascus steel(usually using VG10 steel as core steel), which has an important meaning in the history of human steel.
The original Damascus steel is a wrought iron in which a pattern is generated by the separate crystallization of steels with different melting points due to internal crystallization when the melted cast iron is slowly solidified in a crucible. It is generally known as a general term for materials that artificially create patterns by forging dissimilar metals such as steel and wrought iron. This pattern is caused by differences in carbon concentration and hardness of steel materials, and there are various ways to create the pattern.
During the forging of this special metal, the metal structure is homogenized and impurities are reduced, that makes it possible to produce a blade with extremely high precision.
Ripple Patterns of Damascus
The ripple pattens of Damascus are very well recognized as synonymous with cutting blades as well as mystery.
So how can this ripple be created? The original ripples of Damascus steel appear to have occurred when steels with different melting points were crystallized separately due to internal crystallization when they slowly solidified in the crucible. However, this manufacturing method has not been reported at present, and the modern Damascus pattern is formed by layering dissimilar metals in multiple layers.
By stacking these layers and forging the material, as is known for Japanese sword technology, it produces a very good blade. This is because the structure of the material becomes finer and more uniform in the process of rolling and forging a multi-layered material, which makes it harder than a single-layered material and eliminates the deviation of the blade.
If nothing is done, the cross sections of the layers will only come out in parallel, but by hitting and forging with a hammer again when processing the blade, ripples like the annual rings of that unique tree will be generated.
However, since the ripples themselves are not particularly colored, they cannot be clearly recognized as they are. Therefore, shot blasting (a processing method in which very fine sand and glass beads are sprayed at high pressure) is applied on this blade to make the pattern stand out. As a result, the difference in hardness becomes a pattern and emerges.
Another way to make the pattern stand out is to soak it in acid heated to a certain temperature to make the pattern stand out depending on the degree of corrosion.
