Is there any research on specific details of ancient/medieval blacksmithing related to microelements added via plants?

Upvote:3

I'm not sure about magic/ritual uses, and I'm not sure anyone could answer the 'why' someone tried something (until, at least, the scientific method) but there is evidence for seemingly random - but evidently useful - ingredients in metal work.

For example, cupellation, a technique for refining silver used in Roman period through to the 17th Century CE included a hearth lined with bone ash, a porous material that would absorb the molten oxidised metals (eg. copper).

Sadly, it looks like rare materials such as molybdenum were not widely used (including Japan) until an industrial process for formation/extraction was developed in the 18th century. However, in the process of creating a carbon steel, ingredients such as graphite were used which could contain the material.

Until then, it was probably dumb luck to find that a material had a hardening (or other characteristic) quality - if these pioneering blacksmiths even knew what they were doing. Certainly the spirit of experimentation with processes and alloys had led from copper through tin, bronze, iron and steel.

In terms of the 17th century CE Japanese example, perhaps it would be better to look at the reasons for this possible experimentation, namely the poor iron deposits on the Japanese islands and the need to work this into harder metals.

American Iron and Steel Institute (1948) Steel Facts, Volumes 88-141

Söderberg, A (2011) Eyvind Skáldaspillir’s silver – refining and standards in pre-monetary economies in the light of finds from Sigtuna and Gotland

Upvote:3

Plants have indeed been used to make steel suitable for swords.

Perhaps the most famous ancient swords were the so-called Damascus swords, made of wootz steel. They were called Damascus swords because the steel had a surface pattern that looked like damask. Wootz steel originated in south India around 300 BC, and around 2000 years ago was thought to be the finest steel in the world.

https://en.wikipedia.org/wiki/Wootz_steel

To produce this, a small amount of iron, bamboo charcoal and the leaves of certain plants was put into a hermetically sealed clay crucible, and heated for a long time at temperatures of up to 1200ºC. The crucible had to be small to achieve those temperatures.

The iron was partly carburised (infused with carbon) by the charcoal, which lowered the melting point of the resultant alloy enough to achieve partial melting, which helped spread the carburisation. The result was a small cake of steel at the bottom of the crucible, with a carbon content of around 1.5%. It also included some other trace elements, such as vanadium and titanium, possibly from the bamboo or the other plants. This enhanced the hardness of the steel. The speculation is that the plants were originally included to ‘purify’ the steel, perhaps in a sort of religious rite, but adding them provided the trace elements needed to harden the steel.

This ‘crucible’ technique spread through central and east Asia, but not to Europe. The steel was only ever produced in small amounts, but its production in India lasted until the 19th century, at which point it was replaced by European steel.

Some references for this:

Alan Williams: The Sword and the Crucible

Madeleine Durand-Charre: Damascus and Pattern-Welded Steels

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