STEAD, JOHN EDWARD

(b. Howden-on-Tyne, Northumberland, England, 17 October 1851; d. Redcar, Yorkshire, England, 31 October 1923)

Metallurgy, analytical chemistry,

Stead was the younger brother of the journalist W. T. Stead (1849–1912).

Educated privately because he was not robust, Stead was apprenticed at the age of sixteen to John Pattinson, the chemical analyst of Newcastleupon-Tyne. Three years later he worked at Bolckow, Vaughan and Company, an iron manufacturing firm in Garston, from which post he was able to attend evening classes at Owens College (later the University of Manchester). At the age of twenty-five he became a partner to Pattinson and remained an analyst for the remainder of his life. His original work arose from metallurgical problems encountered in the course of his large commercial practice.

Stead studied eutectics in steels and used his findings to interpret such phenomena as the occurrence of blast-furnace “bears,” which were large inclusions of metal formed in the hearth. He also studied the crystalline structure of metals, and was one of the first to recognize the significance of Sorby’s work in metallography, which he advanced by such techniques as the heat-tinting of specimens. Stead learned a great deal about the effects of phosphorus on steel. Early in his career he explained the afterblow–essential in the basic Bessemer process, for the complete dephosphorization of phosphoric iron–as a result of the removal of phosphorus by iron oxide after the depletion of all the carbon. Another phenomenon connected with phosphorus was that of “ghosts,” superficial markings on forgings, which cause the forgings to be suspect. Stead showed that the markings are due to the difference in solubility of carbon in parts of a steel of different phosphorus content. He also showed that these differences, although visible, are not detrimental in the absence of slag inclusions.

Stead’s experimental studies were not confined to the laboratory, and many steelworks on Tyneside offered him facilities for study under working conditions. In 1901 Stead was honored by the Bessemer Medal of the Iron and Steel Institute, and two years later he became a fellow of the Royal Society. He also received honorary doctorates from the universities of Manchester, Leeds, and Sheffield.

BIBLIOGRAPHY

Obituary notices on Stead are H. C. H. Carpenter, in Proceedings of the Royal Society, 106A (1924), i–v, with portrait; and an anonymous author, in Engineering, 116 (1923), 598–600, also with portrait.

Frank Greenaway