Abstract
Purpose of this study for the possibility of development from mild steel or soft iron to steel, to smith using iron nails for roofing tiles with low concentration of the carbon as source material.
It analyzed to the change of carbon concentration and the structural change of a metal structure in iron made in each process of the smith. The smith similar to making the Japanese sword after the iron nail had been made detailed like the plate.
The analysis used the furnace-combustion infrared absorption method for the determinate of the carbon, and used an optical microscopy and the EPMA analysis for the analysis of a metal structure.
As a result, that was rose up to about 2.6% of the carbon in the mass of iron after carburizing from about 0.1–0.3% of the carbon in iron nail of source material. At the same time, graphite flakes extracted in metal structure, that it was the gray cast iron. The concentration of the carbon decreased to about 0.6% in the iron material after smithed, and then graphite flakes were lost.
It was confirmed to be able to adjust the concentration of the carbon, which develop from iron with low concentration of the carbon to steel.
