Characteristics and Benefits of Real Wrought Iron

Definition of Real Wrought Iron;

    A two component metal consisting of high purity iron and iron silicate -an inert, non-rusting glass like slag. These two materials are merely mixed and not chemically joined as in an alloy. Slag amount from 1% to 3% in the form of small fibers up to 200,00 per inch of cross section. (1)
 

Hand Process

    One or two workmen would take a bloom of pig iron from a blast furnace to a reverberatory furnace and constantly stir the 100 to 500 pound  spongy lump to reduce the carbon, slag, and impurities. At some point it would then be hammered to bring slag to acceptable level. Because of the large amount of highly skilled labor required to produce it, wrought iron was replaced in the late 1800's by steel which could be produced much cheaper and faster.
 

Factory process

    Started in 1930, pig iron is purified in a Bessemer converter, poured into a processing machine with an exact amount of iron silicate slag, and mixed. Then  the 6000 pound bloom is put in a large press to eject surplus slag and weld particles into a uniform mass. This process was the result of many studies on the qualities of wrought iron and steel. In 1905, about 15 years after the general use of steel, a group of American farmers appealed to the Department of Agriculture to investigate the cause of  "fence wire corrosion". The conclusions from the Dept. of Ag. were in part, "The modern Bessemer, or open hearth steel rusts more rapidly than iron wire, and manganese, especially if it is unevenly distributed in the steel, is at least in part  the cause of the trouble." (1)
 

Qualities of Real Wrought Iron

    Principal Virtues of Wrought Iron-
        Are its ability to resist corrosion and fatigue failure. The slag fibers in wrought iron are present in such great numbers that they serve in one capacity as an effective mechanical barrier against corrosion and, under most conditions, force it to spread over the surface of the metal rather than pit or penetrate. Any film or layer of corrosion on the surface, although microscopic in thickness in many cases, affords a high degree of protection to the underlying metal in much the same way that a scab protects a wound. (1)

    Real wrought iron has long been regarded as the traditional material worked by the blacksmith, and its replacement by mild steel is still a matter of regret amongst older craftsmen. Two of the qualities possessed by wrought iron are its ability to be drawn out - "ductility", and its ability to be hammered into shapes - "malleability". It is these special characteristics which make wrought iron eminently suitable for decorative iron work, for which it is still preferred by many blacksmiths. The texture of wrought iron improves with careful forging and it can be worked and welded into the most intricate, delicate, and graceful shapes with greater ease than mild steel. (2)
 

Real Wrought Iron Company - For more information on real wrought iron availability, use, and restoration.

1- "Wrought Iron - Its Manufacture, Characteristics, and Applications"  by James Aston and Edward Story of The A. M. Byers Company, 1936

2-  "The Blacksmiths Craft" - Rural Development Commission, U. K.

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Last updated October 22, 2001