The English ironmaster Henry Cort (1740-1800) made possible the large-scale and inexpensive conversion of cast iron into wrought iron, one of the most essential materials of the early industrial revolution.
Henry Cort was born in Lancaster. His father was a mason and brickmaster. Young Cort became a supplier of naval provisions and by the 1770s had accumulated a small fortune.
In 1775, after years of experimenting with improved methods for wrought-iron production, Cort purchased a forge and slitting mill at Fontley. He tried to find an easy way to convert cast iron into wrought iron; traditionally a smith had hammered the iron in a forge. He patented grooved rollers in 1783 which replaced most of the hammering. By 1784 Cort worked out a process of pudding, whereby molten pig iron was stirred in a reverberatory furnace. As the iron was decarbonized by air, it became thicker, and balls of "puddled" iron could be removed as a pasty mass from the more liquid impurities still in the furnace. Puddled iron, like wrought iron, was tougher and more malleable than pig iron and could be hammered and finished with the grooved rollers. He also devised a process whereby red-hot iron was drawn out of the furnace through grooved rollers which shaped the puddled iron into bars, whose dimensions were determined by the shape of the grooves on the rollers. The rollers also helped squeeze out impurities, and preliminary shaping into bars made the iron more readily utilizable for the final product.
There were many advantages to these processes. Puddling used the plentiful coke, instead of the expensive charcoal. The combination of puddling and grooved rollers was a process that could be mechanized, for example, by the steam engine, which had just been introduced. The result was that production of wrought iron was increasingly carried out in a group of coordinated processes in a single economic unit, with reverberation processes in a single economic unit, with reverberation and blast furnaces operating side by side. This increased production at a greatly reduced cost, and for the first time iron became one of England's exports.
To obtain more capital, Cort took a partner, Samuel Jellicoe, who put up large sums of money. Jellicoe's father had embezzled these funds from the British government, and when this was discovered, Cort was completely ruined and lost his patent rights. As an acknowledgment of the value of Cort's patents, however, the government granted him a small pension in 1794. Cort died a poor man; he was buried in Hampstead, England.
- There is no biography of Cort. Material on him can be found in T. S. Ashton, Iron and Steel in the Industrial Revolution (1924; 2d ed 1951) and The Industrial Revolution: 1760-1830 (1948; rev. ed. 1964). John C. Hammond and Barbara Hammond, The Rise of Modern Industry (1925; 9th ed. 1966), is a classic study that includes information on Cort.
- Mott, R. A. (Reginald Arthur), Henry Cort, the great finer: creator of puddled iron, London: Metals Society, 1983.