Malleable Cast Iron Bars
Malleable Iron Castings
The publicity which Reaumur voluntarily gave to his researches forms a notable exception to the customs of those days when it was the usual thing for manufacturers jealously to guard all trade secrets. These were handed down from father to son or to others of close interest in the business. So aside from Reaumur’s announcements concerning malleable iron, few details of its manufacture came to light during the eighteenth century. Even during the hundred years which have just passed there have been few lines in which greater secrecy has been maintained both in Europe and America. During the last thirty years, only, has real scientific work been done to make known the reactions which occur during annealing and the real causes of the malleability.
The father of malleable iron in this country was Seth Boyden, of Newark, New Jersey, a very ingenious man who well deserves the monument erected in his honor by the citizens of the city, which is pardonably proud of him.
Test Sprues, Showing White, Slightly Mottled, Medium Mottled, and Gray Fractures
Boyden apparently had no knowledge of the existence in Europe of the malleableizing process, but after noticing that a piece of formerly brittle cast iron had become rather malleable, apparently through the action of heat, he set about making experiments to produce a malleable material which could be produced more cheaply than wrought iron. By melting in a forge pieces of pig iron and then annealing in a small furnace in his kitchen fireplace the bars which he cast from the melt, he had worked out by 1826 a process that produced cast iron which was malleable. In 1831 he started a foundry and made a thousand or more different articles for which there was demand, and, from this beginning, an immense industry developed in this country.
