Abstract
The macro- and micro-structure of the iron nails for roofing tiles of the Mieidou at the Senjuji temple in Mie, produced in the Edo period, have been investigated using an optical microscope and an SEM for the elucidation of the nails production method. The object of this work is to obtain materials science data of the Japanese old nails for roofing tiles. The test pieces were mainly cut at the longitudinal direction and partially cut at the horizontal direction for the confirmation of carburizing method. The average chemical compositions are as follows; 0.03 mass%C, 0.06 mass%Si, Mn<0.01 mass%, 0.031 mass%P, S<0.005 mass%, Cu<0.01 mass% and Ti<0.005 mass%.
The matrix structure is mainly equiaxed ferrite grain, whose grain sizes were from 20 to 100 μm. Moreover, we confirmed that the only one side of the nails was carburized clearly at the depth from 0.3 to 1.0 mm. These results show that the forged pieces of the nails were cut from a carburized plate and forged individually.
