The Beginnings of Cheap Steel

Excerpt

The development of the world's productive resources during the 19th century, accelerated in general by major innovations in the field of power, transportation, and textiles, was retarded by the occurrence of certain bottlenecks. One of these affected the flow of suitable and economical raw materials to the machine tool and transportation industries: in spite of a rapid growth of iron production, the methods of making steel remained as they were in the previous century; and outputs remained negligible.

In the decade 1855-1865, this situation was completely changed in Great Britain and in Europe generally; and when the United States emerged from the Civil War, that country found itself in a position to take advantage of the European innovations and to start a period of growth which, in the next 50 years, was to establish her as the world's largest producer of steel.

This study reviews the controversy as to the origin of the process which, for more than 35 years provided the greater part of the steel production of the United States. It concerns four men for whom priority of invention in one or more aspects of the process has been claimed.

The process consists in forcing through molten cast iron, held in a vessel called a converter, a stream of cold air under pressure. The combination of the oxygen in the air with the silicon and carbon in the metal raises the temperature of the latter in a spectacular way and after "blowing" for a certain period, eliminates the carbon from the metal. Since steel of various qualities demands the inclusion of from 0.15 to 1.70 percent of carbon, the blow has to be terminated before the elimination of the whole carbon content; or if the carbon content has been eliminated the appropriate percentage of carbon has to be put back. This latter operation is carried out by adding a precise quantity of manganiferous pig-iron (spiegeleisen) or ferromanganese, the manganese serving to remove the oxygen, which has combined with the iron during the blow.

The controversy which surrounded its development concerned two aspects of the process: The use of the cold air blast to raise the temperature of the molten metal, and the application of manganese to overcome the problem of control of the carbon and oxygen content.

Bessemer, who began his experiments in the making of iron and steel in 1854, secured his first patent in Great Britain in January 1855, and was persuaded to present information about his discovery to a meeting of the British Association for the Advancement of Science held at Cheltenham, Gloucestershire, in August 1856. His title "The Manufacture of Iron without Fuel" was given wide publicity in Great Britain and in the United States. Among those who wrote to the papers to contest Bessemer's theories were several claimants to priority of invention.

Two men claimed that they had anticipated Bessemer in the invention of a method of treating molten metal with air-blasts for the purpose of "purifying" or decarbonizing iron. Both were Americans....