Robert B. Gordon (2) (1929–)
Autore di The Texture of Industry: An Archaeological View of the Industrialization of North America
Per altri autori con il nome Robert B. Gordon, vedi la pagina di disambiguazione.
Sull'Autore
Robert B. Gordon is a professor of geophysics and applied mechanics at Yale University
Opere di Robert B. Gordon
Etichette
Informazioni generali
- Nome legale
- Gordon, Robert Boyd
- Data di nascita
- 1929-12-25
- Sesso
- male
- Attività lavorative
- geologist
university professor - Organizzazioni
- Yale University
Utenti
Recensioni
Premi e riconoscimenti
Potrebbero anche piacerti
Autori correlati
Statistiche
- Opere
- 8
- Utenti
- 88
- Popolarità
- #209,356
- Voto
- 3.5
- Recensioni
- 2
- ISBN
- 18
Author Robert Gordon, a Yale geophysics professor, apologizes in the front matter for excluding Mexico and including Canada in “America”. The initial source was bog iron, iron oxyhydroxide produced by bacteria; it was literally possible to grow iron ore as a crop (it took about 20 years for a bog iron deposit to renew). Using a method known for millennia, a smith threw the lump extracted from the bog on a charcoal fueled forge with a hand-pumped bellows, heated it until malleable, and hammered until the slag moved to the outside. The chemical reaction necessary was reduction – removal of oxygen – and the reducing agent was carbon monoxide; that’s still the way you make iron, although the process has become increasingly elaborate.
The next step was the blast furnace; there was one in Massachusetts by 1641. This stacked charcoal, iron ore, and limestone in a tower, set the charcoal on fire, and blew air through with water-powered bellows or piston pumps. The limestone’s there to act as a flux, combining with gangue in the ore to make an easy-to-remove calcium silicate slag; it seems that some of the early furnace operators didn’t quite understand the chemistry involved and used gabbro instead of limestone (there was just barely enough calcium in gabbro to make this work). That develops one of Gordon’s themes; until the end of the 19th century, iron working was much more of an art than a science. Iron manufacturers and iron users didn’t understand the chemistry of the smelting and refining processes or the metallurgy of the finished product but depended on years of experience and artisanal knowledge to make and use iron.
This caused some interesting problems; the US government contracted with the Franklin Institute to develop methods to test iron (Gordon claims this was the very first scientific research sponsored by the United States government). The Franklin Institute came up with a machine to pull an iron bar until it broke, thus measuring the tensile strength (there were provisions for heating or cooling the iron to test at different temperatures). However, it wasn’t understood that tensile strength is only one of the properties contributing to the overall mechanical performance of iron, especially for the applications the US government was interested in (boilers and firearms) – hardness and especially ductility were equally or more important. This lack of understanding contributed to a lot of pseudoscience about iron – that the properties were influenced by whether the iron was made with charcoal or coke or anthracite; whether the blast furnace used a hot (preheated) blast or a cold blast; how long the molten iron was held in a crucible before pouring; and so forth.
Similarly, the Americans had a very hard time with steel; early manufacturers produced steel with very irregular properties, to the extent that all major American firms using steel bought it from England (when American firms finally did get the knack of making quality steel – it turned out to hinge on properties of the clay crucibles used – they lied about the source and advertised it as “Sheffield steel”, since American steel had acquired such a bad reputation).
I learned a great deal here – the difference between a bloomery, a finery, and a puddling furnace; how a reverberatory furnace works and why you would want one; what a cementation furnace does; how blister steel becomes crucible steel; what a Bessemer converter does, and why the open-hearth furnace replaced it; and the difference between a tilt hammer, a helve hammer, and a steam hammer. There are lots of illustrations, mostly photographs of ironworks and diagrams of various kinds of equipment; maps of iron mining and iron and steel production areas; an excellent glossary; and an extensive bibliography. Gordon laments that historical museums focus on the very early sites – charcoal forges – and on large buildings – blast furnaces – but later and less spectacular developments have been ignored – there are no bloomeries, fineries, puddling furnaces, cementation furnaces, or crucible steel sites on exhibit. Very worthwhile.… (altro)