Wrought iron is a very pure form of commercial iron, having a very small carbon content. It is tough, malleable, ductile and can be easily welded. However, it is too soft to make blades from; steel, with a carbon content between wrought and the high-carbon brittle cast iron, is used for that.
Wrought iron is produced from pig iron by melting it and adding oxides that would react with the carbon to produce carbon dioxide, which then bubbles out.
Historically, this would be followed by faggoting. Wrought iron which had been faggoted twice was referred to as "Best"; if faggoted again it would become "Best Best", then "Treble best", etc.
Faggoting resulted in impurities within the metal ending up as long thin inclusions, creating a grain within the metal. "Best" bars would have a tensile strength along the grain of about 23 tons per square inch. "Treble best" could reach 28 tons per square inch. The strengths across the grain would be about 15% lower.
