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Peruvian steel or argentine steel, or silver steel, is the name given to an early type of non-rusting(?) crucible steel alloy, containing approx. 0.002% silver. It was developed by Michael Faraday and Charles Pickslay between 1822–1824, following earlier scientific investigation of Wootz steel by James Stodart (and later Faraday) between 1796–1822/23. (Query to self: when did Stodart die?) Various high-quality items such as razors and scissors made of Peruvian steel were manufactured and sold from 1824-1834 by the Sheffield firm of Appleby, Pickslay and Bertram, and by Adam Padley of that city from 1834-1844.

Because Peruvian steel contains no chromium, it is by definition not classed as a stainless steel and thus is little mentioned in the history of the development of stainless; but it is certainly an example of an non-oxidising steel with many similar properties to stainless.

Peruvian steel is not related to modern silver steel, an alloy tool steel which contains no silver.

History
Towards the end of the 18th century, a growing need in Europe for corrosion-resistant steels became the basis for more precise scientific investigations into steel alloys. Christlieb Ehregott Gellert (1713-1795) describes techniques for alloying gold and silver with iron using a cementation process involving pulverised brick dust, colcothar (a type of ferrous oxide, and saltpetre (Potassium nitrate). He also cautions against the "useless, superfluous, partly expensive and often noxious mixtures found in several authors".

Oregrounds iron
Until the 19th century, only iron from certain ores, found in a few localised mining areas, was suitable for converting into steel. These iron ore deposits (now mostly worked out) were relatively free from two major impurities which have a negative effect on the making and use of carbon steel: sulphur and phosphorus. These two (mostly unwanted) contaminants are present in significant amounts in most known worldwide deposits of iron ore, and until the 19th century this was the limiting factor in the development of large-scale worldwide manufacture of steel. Until the invention of various refinements to Henry Bessemer's process for converting pig iron) into steel during the 19th century, there was no technique for casting plain carbon and alloy steels in large-scale industrial quantities from lower-quality iron ores with a higher sulphur and phosphorus content.


 * Sulphur

During the production of steel, sulphur makes the molten steel pour less easily, and makes the steel brittle and unworkable when hot (i.e. red short). Sulphur also adversely affects the toughness of the finished steel, although it can be advantageous in some circumstances to have very small amounts of sulphide inclusions which makes the steel more workable in the lathe (i.e. giving a "short chip").

Sulphur may be present as a contaminant in the ore itself, or in mineral fuel (such as coke or coal) if used in the furnace. Ore from the Dannemora mine had a low sulphur content, and in addition Oregrounds iron was smelted using charcoal as fuel (which contains no sulphur). The Dannemnora ore also contains high levels of manganese, (Note to self: update Manganese article with more steel info which is a de-sulphurising agent; it prevents sulphur from forming iron sulphides in the melt (the cause of its red shortness) and instead preferentially forms a slag of manganese sulphide (MnS). In concentrations of between 4-8% manganese also makes steel brittle when cold, above 8% it it keeps steel austenitic at room temperature.

Although it was possible to remove sulphur during Henry Cort's puddling process by the addition of rust (iron oxide), it wasn't until 1856 that Robert Mushet's experiments with spiegeleisen (a type of ferro-manganese), led to his development of the Acid Bessemer process: this finally made it possible to produce cast steel straight from the blast furnace on a large-scale industrial basis, from previously unusable ores with a higher sulphur content. In a


 * Phosphorus

Phosphorus makes the steel unusably brittle when cold (i.e. cold short) although it lowers the melting point and allows the molten steel to run more freely. Before the late 19th century, only a few scattered iron ore deposits in Europe had a phosphorus content low enough for successful steel-making, and the Dannemora mine in Uppland has among the the lowest of all (between 0.001-0.005%).

High phosphorus levels in iron ore remained a world-wide barrier to mass production of steel until the introduction of the Thomas-Gilchrist basic Bessemer process in 1879. This used a limestone (CaCO3) flux to remove phosphorus in the slag as calcium phosphate (an early example of industrially-produced fertiliser.) Also Calcium Oxide (CaO + SO2 ??) and Dolomitic lime CaMg(CO3)2.

In the UK:
 * Deposits of low-phosphorus iron ore
 * Forest of Dean (Gloucestershire)
 * Blaenavon, (S. Wales)
 * West Cumbria & Furness
 * Airdrie black band, Garturk Estate, Coatbridge (discovered in 1801 by David Mushet)

In other places:


 * Dannemora (S. Sweden)
 * Bilbao (Catalonia, N. Spain)
 * Siegen (Westphalia, Germany)
 * Styria and Carinthia (Austria) (Eisenerz )
 * Island of Elba
 * Adirondack, NY, USA
 * Michigan, USA
 * Kerala (S. India)

LOCALITIES AND ORES.

Background

 * Crucible steel

1n 1740 Benjamin Huntsman started to manufacture a type of crucible steel, suitable for watch springs. This was made from imported Swedish bar iron from Dannemora The processes involved were as follows:

Ore was smelted and forged in Sweden into bar iron. The bars were made flatter to maximise the uneven carbonisation that takes place during the cementation process. The resulting blister steel was then treated like wrought iron (i.e. repeatedly forged and hammered in a trip-mill). This shear steel (the process was repeated for 'double-shear') was then broken up and packed into crucibles along with a flux (often glass) which did something.

This lengthy and expensive process produced about a ton of steel per week, much of which was exported to France.

Wootz steel
In July 1794 the President (director?) of the Royal Society, Sir Joseph Banks, received some 'trifling specimens' or (cakes) of Wootz steel (a type of crucible steel) from Dr. Helenus Scott, an East India Company military surgeon and botanist in Madras, India. He distributed the samples to various friends of his for scientific investigation. Sir Thomas Frankland, 6th Baronet, had a piece worked into a thick bar; Matthew Boulton received some in June 1795, and in the same month George Pearson read his paper to the Royal Society on his findings on the steel.

In 1796 Scott sent a further 183lbs. of wootz to Banks; the previous samples were not so hard as the English sort and had not been "worked properly". It was probably a sample of this shipment that Banks gave c.1796 to John Stodart, a member of the Royal Society and maker of razors and surgical instruments. Stodart was interested in non-oxidising steels to improve the quality of his products. He managed to make three penknives from the steel: one for Banks, one for King George III and one for someone in Paris who? find ref - prob,. Pearson 1795. Stodart went on to experiment with gilding other metals, such as steel and brass, with platinum.

David Mushet also experimented with a sample from Banks, publishing papers in 1804 and another year Mushet had discovered a low-phosphorus iron ore near Coatbridge in 1801, and bought a disused ironworks on the banks of the River Calder to profit from his efforts.

Stodart later continued his investigations with the young Michael Faraday. Faraday, who had been appointed as Chemical Assistant at the Royal Institution by Sir Humphry Davy on 1 March 1813,[4] was also familiar with platinum.

Faraday's Peruvian steel
Stodart and Faraday continued their work, publishing papers on wootz in 1818 and 1819 respectively.

Together they conducted laboratory experiments with various crucible steel alloys including platinum, rhodium nickel and silver. Faraday built his own furnace and crucibles to carry out their experiments. Their eventual success was partly due to the high-quality oregrounds iron from the Dannemora iron ore mine in Sweden. Its low phosphorus content (as little as 0.001%) was essential to avoid brittleness in the steel, and the high managanese content of the Dannemora ore removed combined with other impurities to form slag, and what remained contributed to the steel's hardness.

In 1820 they co-authored a paper in the Royal Institution's Quarterly Journal on their findings, remarking that the steel-silver alloy was "decidedly superior to the very best steel."

Faraday and Stodart continued to experiment; by 1822 they reported that they had succeeded in making a high-quality rustless alloy of crucible steel and 0.002% silver on a limited industrial basis (using pig iron from the Dannemora mine in Sweden) at the foundry of Thomas Sanderson in West Street, Sheffield.

However, Stodart died in 1823. Although Faraday turned to other matters, (which ones?) he continued to have the steel developed further, in conjunction with the Sheffield firm of Pickslay, Appleby and Bertram.

Charles Picsklay
Charles Pickslay had formerly been a partner in Green, Pickslay and Co., originally ironmongers in Sheffield High Street. Green left the company in 1823. In 1824 Pickslay having experimented with the alloys recommended by Faraday, sent him a steel specimen alloyed with silver, iridium and rhodium. . . “furnished by Mr.Johnson, No 79 Hatton Garden”. By 1828 Pickslay, Appleby & Bertram of the Royal York Showrooms,in Sheffield High Street were the sole manufacturers of Peruvian Steel Cutlery.

Green formed a partnership with Adam Padley in 1828. Adam Padley was a fender maker from Rockingham Place. In 1834 Padley registered the PERUVIAN mark and proclaimed himself as the only maker of Peruvian Steel, made by a process "only known to Himself". Padley died of apoplexy in 1844.

Although Pickslay and Co. ceased business after going bankrupt in 1843, In around October 1844. an American iron ore mine manager and iron founder named David Henderson from Adirondack, NY state, travelled to England (NB Hmm, possibly - ref Manchester p. 6) to investigate the possibility of making high-quality steel from the iron which his mine produced. Henderson had had some success making steel directly from the pig iron, using charcoal. He went to Sheffield and met Pickslay. who agreed to help him. Pickslay and his son William Morton Pickslay returned to the States with Henderson to see for himself how the new process worked and initially was quite keen to be involved in the new venture. However, although Pickslay had some success in creating high-quality steel from samples, he eventually decided against becoming involved.

In later life, Faraday would occasionally present one of his friends with a razor made of his own special steel.

Etymology
A contemporary (1821) scientific dictionary defined "argentine steel" as an alloy containing 0.002% silver (i.e. 500:1). In this context "argentine" derives from the Latin word for silver, argentum, and not from the Argentine Confederation which only received its modern name in 1831. The name "Peruvian steel" may well be a type of pun or humorous back-formation from "argentine steel". Peru (a major source of silver) declared its independence from Spain in 1821 - around the time Faraday and Stodart's alloy was first manufactured - becoming essentially free from Spain in 1824.