Pattern-welded Steel

The first occasional smelts of steel took place in Syria and Iraq around 2700 B.C. First smelts in reproducible form date back to 1400 B.C. in Anatolia. From there the knowledge spread over whole Europe within the next 1000 years. During this period many steel working techniques were invented and improved until steel products finally were superior to bronze. The gradual transition from bronze to steel required the use and perfection of very different techniques. Bronze was cast and work-hardened, whereas steel was hot-forged, quenched and tempered.

The antique smelting furnaces did not produce wrought iron in quantities and qualities that could be used directly. The gained puddle-balls were spongy, of uneven quality, and interstratified by impurities. They were forged flat, quenched, and broken into pieces. These were sorted by quality and forge-welded to bars of usable size. These bars had to be refined by subsequent folding until the steel was sufficiently homogenous. Sometimes the smiths combined these bars while forging in a manner to produce -beside the desired mechanical properties- decorative patterns, often the serpent pattern. Those blades had a prosperity between the 5th and 10th centuries A.D. The decorative pattern vanished from European Swords in the succeeding centuries, although refined steel was used. This is probably related to many different factors, changed requirements for blades are likely to be only some of them.

The wars against the Turks brought damascene steel back to central Europe. Pattern welding had a renaissance with the emersion of firearms. Still, the patterns have to be seen as a decorative elements.

In the 14th century, the controlled production of cast iron was developed. The ease of working this material caused a wide spread use of cast iron for every day products. Cast iron is not suited for edged weapons. In the 18th century, larger amounts of wrought iron could be smelted due to the development of industrial fining and decarburizing processes. The labor-intensive refined steels were replaced by mono-steel -now available in sufficient amounts and quality-.

Despite the long tradition of Damascene steel in Europe, its techniques were nearly forgotten and had to be revived in the 20th century. Important impulses came from M. Sachse and H. Denig, in America from B. Moran and others. Still there is much unknown or misunderstood about this type of steel. The most pronounced example is probably the idea of soft and hard layers in the cutting edge–a wide spread misunderstanding. Several researchers have proven that due to diffusion, carbon-equalization is complete after a few folds. The speed of carbon migration is commonly underestimated.

The intention of this page is to answer some of the most common questions about pattern-welded steel and to consider it from a technical point of view. Many observations can be explained by basic knowledge about behavior and metallurgy of steel. It becomes clear that Damascene steel can only be superior to mono-steel to a limited extent. Cutting tools made from joint steel are rather highly optimized for one purpose and are not likely to have superb performance for all purposes.

I started forging Damascene steel in 1999. At the same time I started to study the theory of carbon steel. In Mr. U. Gerfin I had found a great teacher, giving practical advice as well as providing a well-founded theoretical background. The access to this topic was eased by my study of space and aircraft and my employment at the Institute of Statics and Dynamics of Aircraft Constructions at the University of Stuttgart, providing access to scientific equipment.

The pictures are linked to higher resolution pictures to reduce loading-time of the pages. In addition the most important terms are combined into a glossary.

© 2005 G.v.Tardy