Damascus steel

What is Damascus steel?

The name covers two different things.

Historic Damascus steel describes sword blades traded through the Middle East from the medieval period. They were forged from wootz, a crucible steel made in India and Sri Lanka. The pattern came from bands of hard carbides inside a single steel, brought out by careful forging and etching. The name is usually linked to the city of Damascus, a centre of the trade, though historians debate the origin.

Modern Damascus steel is pattern-welded: layers of different steels forge-welded into one bar. The idea is old. Smiths in early medieval Europe made pattern-welded sword blades centuries before the word "Damascus" was used for them. Almost every Damascus knife sold or made on a course today is pattern-welded.

How is Damascus steel made?

1. Choose two steels that harden alike but etch differently. The usual pair is 1084 or 1095 with 15N20, whose nickel stays bright after etching.
2. Stack alternating plates, often 7 to 15 layers, and tack them together.
3. Forge weld the stack: heat it to welding heat, around 1,250 °C, often with borax flux, then hammer or press the layers into one solid billet.
4. Draw out and restack. The billet is drawn longer, cut and restacked. Each time the layers multiply: 15 layers restacked four ways becomes 60, then 240.
5. Make the pattern. Twisting, grinding grooves or pressing dies into the billet creates patterns such as twist, ladder and raindrop. Left alone, the layers give a random "wood grain".
6. Forge, harden and grind the blade as with any knife.
7. Etch the finished blade in diluted ferric chloride. The two steels darken differently and the pattern appears. Some makers then dip it in strong coffee for deeper contrast.

Forge welding means working steel near its melting point. It's a skill to learn with a smith, not alone.

How many layers does Damascus steel have?

Anything from a few dozen to several hundred. More layers is not better, just different: low counts give a bold pattern; very high counts become so fine they look like plain steel. Most knives sit between about 100 and 300 layers.

Is Damascus steel stronger than normal steel?

No, not by itself. A Damascus blade performs like the steels it is made from, if it is well welded and well heat treated. Poor welds leave weak spots and inclusions. The legend of near-magical Damascus swords comes from historic wootz blades, which were very good steel for their time. A 2006 study of a 17th-century wootz sabre found carbon nanotubes and nanowires in its structure, a clue to how the old smiths' process worked.

How can you tell real Damascus from fake?

• The pattern goes all the way through. On pattern-welded steel, the layers show on the spine and continue across the edge bevel. A pattern that stops at the bevel or looks printed on is a surface etch.
• Ask what steels were used. A maker will tell you (for example 1084 and 15N20). Cheap "Damascus" of unknown steels is often soft.
• Price. A real Damascus billet takes hours of skilled work. Very cheap Damascus knives rarely perform well.

Caring for a Damascus knife

Most Damascus is carbon steel and will rust. Keep it dry and lightly oiled, and never put it in a dishwasher. Heavy sharpening can wear the etch off the edge; a maker can re-etch it.