Excerpt from Unusual Features in the Microstructure of Ferrite Iron is usually considered as having a relatively simple type of microstructure and as being characteristic of pure metals in general. The structure of ferrite (iron) is probably better known to most metallurgists than that of any other metal or alloy. Sometimes, however, commercial iron, such as open-hearth iron, wrought iron, and remelted electrolytic iron, shows rather unusual structural characteristics, to the nature and possible significance of which very little attention seems to have been paid. The most common one of these unusual features, as ordinarily observed, appears in a polished and etched section of the metal as a distinct network pattern in addition to the usual grain-boundary pattern of the ferrite, and has been briefly referred to at times in the literature. Andrewe's descriptionl appears to have been the first one appearing in the literature. He observed that certain specimens of wrought iron, after etching with an aqueous nitric-acid solution (1 per cent), showed what he termed duplex crystallization. Many of the grains of iron or primary crystals had the appearance of being subdivided into a large number of secondary crystals. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.