Early modern steel included Blister Steel manufactured by the cementation process which was first made around the 16th century in Italy and soon after in England were it was produced in Coalbrookdale by Basil Brooke around 1610.Â Wrought iron bars was the raw material used in the process, and was still used up till the 19th century.
Another early modern steel was Crucible Steel which was melted in a crucible rather then being forged.Â This resulted in a more uniform structure with better composition throughout.Â Earlier furnaces could not reach high enough temperatures to melt steel.Â Modern crucible steel resulted from the invention of Benjamin Huntsman in the 1740’s. Blister Steel (same as above) was melted in a crucible in side a furnace, & cast into ingots normally.
Early modern steel era ended and Modern steel making era began with the Bessemer Process named after it’s inventor Henry Bessemer who took out a patent on the process in 1855. although this process had already been used centuries before in china and other countries it was not used on an industrial scale before.Â The process was independently discovered in 1851 by William Kelly. The Bessemer process was the first inexpensive industrial process for mass production of steel from molten pig iron.Â The key to the process is the removal of impurities from the iron by oxidation by air being blown through the molten iron.
the Bessemer Process which revolutionized steel manufacture by cutting cost and increasing production speed and decreasing labor requirements.Â this brought the price of steel down to a similar priced wrought iron, which for the first time in history made steel an affordable material for building bridges or to be used in the frame work for buildings, most manufactures switched from wrought iron to steel after this.Â
With the introduction of the Bessemer process in 1858 the modern steel making era began. The Bessemer process allowed for large quantities of steel to be produced cheaply, effectively replacing wrought iron with steel, however this was just the first of many production methods used in modern steel making most were just improvements on the Bessemer process one of these was the Gilchrist-Thomas process created by Sidney Gilchrist Thomas and cousinPercy Gilchrist devised in 1876-77 this process was widely used in Europe there after.
The Gilchrist-Thomas process of manufacturing in Bessemer converters a kind of low-phosphorus steel known as Thomas steel. In the Thomas – Gilchrist process the lining used in the converter is basic rather than acidic, and it captures the acidic phosphorus oxides formed upon blowing air through molten iron. the Gilchrist-Thomas process was an improvement on the Bessemer process.
Another improvement on the Bessemer process was the Siemens-Martin process, In 1865, the french engineer Pierre-Emile Martin took out a licence from Carl Wilhelm Siemens and first applied his furnace for making steel. Their process was known as the Siemens-Martin process, and the furnace as an "open-hearth" furnace. The most appealing characteristic of the Siemens regenerative furnace is the rapid production of large quantities of basic steel, used for example to construct high-rise buildings. The usual size of furnaces is 50 to 100 tons, but for some special processes they may have a capacity of 250 or even 500 tons. The Siemens-Martin process complemented rather than replaced the Bessemer process. It is slower and thus easier to control.
Both the Gilchrist-Thomas process and Siemens-Martin process complemented, rather than replaced the original Bessemer process
Siemens-Martin Oven below
The Bessemer process was rendered obsolete by the Linz-Donawitz process of basic oxygen steel making developed in the 1950’s, by 1968 most all commercial steel producers stopped using the Bessemer process and replaced it with the Linz-Donawitz process which offered better control of final chemistry. The Bessemer process was so fast (10-20 minutes for a heat) that it allowed little time for chemical analysis or adjustment of the alloying elements in the steel. Bessemer converters did not remove phosphorus efficiently from the molten steel; as low-phosphorus ores became more expensive, conversion costs increased. The process only permitted a limited amount of scrap steel to be charged, further increasing costs, especially when scrap was inexpensive. Certain grades of steel were sensitive to the nitrogen which was part of the air blast passing through the steel.
For the first post on this site it will not be about steel buildings, but about the history of steel it’s self. No one really knows exactly when and where steel was first produced however some of the first steel that we know of comes from East Africa dating all the way back to 1400 BC , in the 4th century steel weapons we produced in the Iberian peninsula. Under the Han Dynasty in china in 202 BC to 220 AD steel was created by melting together Cast Iron with Wrought Iron to make a Carbon - Intermediate - Steel.
Another type of steel was produced in India and Sri Lanka around 300 BC. called Wootz Steel and Damascus Steel, Wootz Steel is Characterized by a pattern of bands and or sheets of micro carbides with in a tempered martensite or pearlite matrix. Wootz Steel was widely exported throughout the region and became famous in the Middle East, where it became known as Damascus Steel. Damascus Steel is a hot forged steel used in Middle Eastern Sword making around 1100 -1700 AD. Damascus Swords were legendary for there strength and sharpness, legend has it they could cut through rock and cut through European swords that were of lesser strength. The formula to create Damascus Steel has been lost in history.
Before the advent of modern metal alloys cast and hot rolled to construction beam sizes, sword makers of antiquity produced steel by the handful. Melting and casting a good alloy the size of a sword was difficult. Hollywood has described a fictional event where a crusader throws down his cast sword that shattered, for a damascene sword, taking home the folded hard and soft steels, changing European sword making forever. In actuality, folding/forging was well known. But this discovery of better metallurgy happened at the beginning of the age of alchemy, and so the legend of Damascus Steel was born. Recent studies have suggested that carbon nanotubes were included in its structure, which might explain some of its legendary qualities, though given the technology available at that time, they were produced by chance rather than by design
Crucible Steel was produced around the 9th and 10th century AD. in Merv.
There is evidence that in Song China in the 11th Century production of Steel using two techniques: a "berganesque" method that produced inferior, inhomogeneous steel and a precursor to the modern Bessemer process that utilized partial de carbonization via repeated forging under a cold blast.
more on the history of steel tomorrow
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