Iron is converted into steel, either by fusion, or by cementation. The former method is employed for making steel immediately from the ore, or from the crude, cast metal. In the latter, bars of iron are placed in furnaces, with a stratum of charcoal between each; till the pile is raised to a sufficient height. The whole is then closely covered, to prevent the access of the air; when a strong fire is kindled, and uniformly continued during the whole process. The surface of the metal, manufactured in either way, generally exhibits numerous vesicles, whence it is called blistered steel; but these may be removed by repeated ignition between red-hot coals, and by forging.
The finest metal of this description, is the Damascus-steel, which is imported from Syria; but the process pursued in the Turkish manufactories, is not accurately known in Europe. The German-steel is made by breaking the blistered bars into small pieces, which are exposed to the strong fire of a furnace: these are next welded, and extended to the length of about 18 inches, when they are doubled ; welded a second time; and at length drawn to the requisite size and shape. The celebrated Bres-cian-steel is obtained by roasting the iron-ore-in strata, with layers of wood between each ; and, when these are sufficiently smelted, the metal is taken out of the furnace, broken to pieces, picked, and washed in troughs of pure water. It is next conveyed to an oblong square cavity, termed the fluxing-bed, which is strewed with a mixture of finely-sifted ashes and sand, that are carefully compressed. A stratum of charcoal is then laid on ; the smelted metal is gradually added ; and, at the end of three or four days, the conversion is completed.
The best steel manufactured in Britain, is known under the name of cast-steel. It is prepared from the common blistered metal j which, being broken to pieces, is put into proper crucibles, with a flux; and, after the fusion is effected, the metal is cast into ingots, when it undergoes the operation of tilting, and is at length tempered, by repeated ignition and immersion in water.
In 1801, a Mr. Eggs obtained a patent for a new method of bending steel. After giving the necessary shape to the blade, spring, or other article, it is extended over a convex piece of iron, denominated a fiat. The bent steel is next stricken repeatedly with an iron machine, resembling a chissel, that cuts into the former, and completes the bending; by which practice he conceives, that considerable labour will be saved in the manufacturing of sp nd surgeons' instruments.
Rusty steel may be cleaned, by first anointing it with sweet-oil, which in the course of two or three days will soften the rust; afterwards wiping it dry with clean rags, and polishing the tarnished parts with pumice-stone or eme-ry, by means of hard wood : but the most effectual composition for giving a high degree of lustre to steel, is a paste made of levigated blood-stone and spirit of wine.
This useful article is subservient, chiefly to the manufactures of sword-blades, table and pen-knives, razors, and a variety of other utensils, employed in the arts, and by mechanics: its medicinal properties differing but little from those of iron, we refer the reader to vol. ii. p. 31. - Steel pays on importation, various duties, according to its respective quality: - thus, the gad-steel is subject to the charge of 2l. 9s. 8 1/2d. per cwt. ; the long and wisp-steel pay 13s. 11 1/2d. per cwt. ; and steel-wire is liable to the duty of 11d. per lb.