Bessemer process

Bessemer process A process for converting pig iron to steel by oxidation of the impurities (C, Si, P, Mn) by blowing air through the molten metal. 

Before the invention of the Bessemer process for steelmaking in 1856, only the cementation and cmcible processes were of any industrial importance. Although both of the latter processes had been known in the ancient world, thek practice seems to have been abandoned in Europe before the Middle Ages. The cementation process was revived in Belgium around 1600, whereas the cmcible process was rediscovered in the British Isles in 1740. 

The various steelmaking processes were all eventually supplanted (3,4). The first of the newer techniques was the historic pneumatic or Bessemer process, introduced in 1856. Shortiy thereafter, the regenerative-type furnace, known in the 1900s as the open-hearth furnace, was developed in the United... 

All steels contain some Mn, and its addition in 1856 by R. Mushet ensured the success of the Bessemer process. It serves two main purposes. As a scavenger it combines with sulfur to form... 

Bessemer-birne, /. Bessemer converter, -ei, /. Bessemer (steel) plant Beasemerizing, -eisen, n. Bessemer iron, bessemem, v.t. bessemerize, Bessemer-schlacke, /, Bessemer slag, -schmelze,/, Bessemer heat, -Stahl, m. Bessemer steel, -verfahren, n. Bessemer process, besser, a. adv. better. 

Birnen-i31, n. pear oil (am3 l acetate), -prozess, m, (Metal.) converter process, Bessemer process. -wein, m, perry. 

Perrin A modification of the Bessemer process which accomplishes the removal of phosphorus from iron by treating the initial molten metal with a molten mixture of lime, alumina, and fluorspar. 

The pig iron is brittle because it contains close to 5 per cent carbon. To turn il into steel, the carbon must be burned out until nnly from. 5 to 1.5 per cent remains. This is done either hy the Bessemer process (named for an Englishman. Henry Bessemer) or by the open-hearth process. The finished steel is molded... 

The Bessemer process, as important as it was, produced only one kind of steel, carbon steel. Carbon steel consists primarily of iron with varying amounts of carbon added to produce a variety of properties. Today, carbon steels come in various forms, known as high-carbon, medium-carbon, low-carbon, extra-low-carbon, and ultra-low-carbon steels, each with a characteristic amount of carbon, ranging from more than 0.5 percent carbon at the high end to less than 0.015 percent carbon at the low end. 

The Bessemer process is relatively less expensive but does not produce a product of high quality. It is not possible to exercise control over the composition of the product because the conversion occurs so quickly. Furthermore, this process does not effect the removal of phosphorus. The phosphorus pentoxide that is formed during the blow is reduced to phosphorus upon addition of carbon and hence remains as an impurity in the final product. Provision for the removal of phosphorus may be made by the use of the so-called basic Bessemer process, which employs a converter lined with magnesia (MgO), but this practice entails other disadvantages. In the United States, the acid Bessemer process is used exclusively and accounts for about 15% of the steel produced in this country. Steel so produced is used largely as structural steel, as reinforcement for concrete, and in the tinplate industries. 

Despite its disadvantages and limitations, the Bessemer process opened a new era of industrial progress. Its use made cheap steel available and was largely responsible for the rapid expansion of railroad building during the latter part of the nineteenth century. 

In comparison with the Bessemer process, the open-hearth process has certain important advantages. It provides accurate control of temperature owing to the use of an outside source of heat. The composition of the final product can be predetermined by analysis and thereby controlled. Complete removal of phosphorus is accomplished, and this permits use of low-grade iron ores, which are usually of relatively high phosphorus content. None of these advantages is possessed by the Bessemer process. 

Henry Bessemer in the 1850s developed the Bessemer Process for mass producing steel by blowing air through molten iron to oxidize impurities. 

Epitome of Process.—The ore is first dressed, roasted, and then smelted in blast or reverberatory furnaces to a ferruginous matte consisting essentially of sulphides of copper, nickel, and iron. This is then oxidised in a blast of air in a converter in an analogous manner to the production of steel by the basic Bessemer process. By this means practically all the iron is removed, and as much sulphur as possible without excessive loss of nickel. On an average the product contains approximately ... 

A hard, compact, nodular variety of haematite is found in Cumberland in the carboniferous limestone series of Cleator Moor, in Furness in North Lancashire, and to a less extent in Devonshire, and from its shape is termed kidney ore. The ore is very low in phosphorus, and is particularly valuable for making Bessemer pig iron—that is, pig iron suitable for the manufacture of steel by the acid Bessemer process. The Furness ore appears to have been worked in prehistoric times. 

Bessemer process for mass production of steel patented... 

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