"It may be remembered that an important part of the process, as described at Chel tenham in 1856, consisted in tapping the fluid crude iron from the blast-furnace, and allowing it to flow direct into the converting-vessel and be there blown to the extent only of decarbonizing it so far as to produce cast steel. This part of the original pro gramme has been most successfully carried out in Sweden, where an extensive esta blishment for its manufacture has been erected by M. Goranson, of Gefle. The large steel circular saw plate exhibited is an example of the conversion of crude cast iron run direct from the blast-furnace into the converting-vessel and there blown for nine minutes, in which period it had been converted into cast steel of the desired quality, and was then poured into an ingot-mould without being recarbonized, and wholly without the employment of spiegeleisen or manganese in any form whatever.* "With these few illustrations of the capabilities of the process, as originally de scribed at Cheltenham, the author will proceed to show how the disadvantages of the old fixed converting-vessel were remedied and other improvements introduced. Mane forms of converting-vessels were tried on the large scale before this desirable object was attained. In some of them the lining was too easily broken down by the violent motion of so heavy a fluid as iron; in some of the forms tried the angles allowed the metal to solidify in them, and so clog up the vessel; in others the mouth of the vessel being too small caused the metal to be thrown out by the force of the escaping blast. It was also found that if the mouth was too large the heat escaped, so as to cause part of the converted metal to solidify in the vessel; the relative height and diameter of the vessel was also found to produce important differences in the working of the process. Finally, and after many long and expensive trials, the form of vessel shown at B was adopted. (See figure 185.) This vessel is made in two parts, so as to admit easily of its being lined up with a pulverized silicious stone known as ganister,' which so resists the action of the heat and slags as to last for fully 100 consecutive charges of steel before it is worn out. Its form is that of the arch in every position which pre vents the lining from falling down by its own weight. There are no angles in which the splashes of metal can solidify and accumulate. Its mouth directs the flame and sparks away from the workman, and from the moulds and other apparatus; while the throat of the vessel, and the position of the mouth, almost entirely prevents the throw ing out of the metal. The vessel is mounted on trunnions supported on stout pedestals, so that a semi-rotary motion may be communicated to it at pleasure. The tuyers are placed at the bottom of the vessel, so as to force the air vertically upward through the metal, as shown, without coming in contact with the sides of the vessel. When the crude metal is to be run into the vessel, it is turned on its axis nearly into the position shown at C, the mouth being a little higher up; a gutter will then conduct the crude cast iron from the melting-furnace into it. It is not necessary to turn on the blast until the whole of the metal is run in, because the tuyers occupy a position above the level of it. As soon as the air is admitted through the tuyers the vessel is turned into the position shown at B, when its decarbonization immediately commences. As soon as this is effected, as much molten pig iron made from spa.those iron ore is added to it as will restore the quantity of carbon necessary to produce the desired quality of steel, which is then run into the casting-ladle in the manner shown, and from whence it is transferred to a series of iron moulds ranged in a semicircular pit, each mould being placed within the sweep of the casting-crane. The filling of these moulds is regulated by a cone-valve made of fire-clay and fitted in the bottom of the casting-ladle, so as to be opened or shut at pleasure by means of a handle on the outside of the ladle.
" 'It will be readily understood that in the fixed vessel first described, any giving way of a fire-clay tuyer would stop the process and cause much inconvenience; but with the movable vessel it is not so, for at any moment of time during the process the vessel may be turned on its axis and the tuyers raised above the level of the metal; the blast may then be turned off, the tuyer-box opened, and the faulty tuyer stopped up or removed, after which the process may be again resumed. The movement of the vessel
on its axis, the rise and fall of the casting-crane, and the other cranes employed for removing ingots from the casting-pit, are all effected by a simple hydraulic apparatus, so that the whole process is under the perfect control of a single operator, placed far away from the heat and showers of splashes that accompany the process.
`Up to this period, the manufacture of cast steel by the old as well as the new pro cess is still so far imperfect that steel of the highest quality cannot be made from infe rior iron. In the old Sheffield process, the original quality of the Swedish charcoal iron employed governs the quality of the cast steel made: consequently, £36 per ton is freely given for the high-class Danemora iron, while other brands of Swedish char coal iron may be bought for £15. In either case, these are expensive raw materials for the cast-steel maker.
" 'In 1839, the trade of Sheffield received an enormous impulse from the invention of Josiah Marshall Heath, who patented in this country the employment of metallic man ganese, or, as he called it, "carburet of manganese." The addition of a small quantity of this metal, say from one-half to one per cent., rendered the inferior coke-made irons of this country available for making cast steel; it removed from these inferior qualities of iron their red-shortness, and conferred on the cast steel so made the property of welding and working soundly under the hammer.
" 'Manganese has now been used for many years in every cast-steel works in Europe. It matters not how cast steel is made, since manganese added to it necessarily produces the same beneficial changes. No one better appreciated this fact than the unfortunate Mr. Heath, as evidenced by his patent of 1839, in which he declares that his invention consists in "the use of carburet of manganese in any process whereby iron is converted into cast steel." Had Heath seen in his own day the Bessemer process in operation, he could not have said more: he well knew the effect produced by manganese on steel, and, therefore, claimed its employment in any process whereby iron is converted into cast steel.
" 'In the Mining Journal of September 24, 1853, just four years before the first of Mr. Mushet's series of patents, a letter was published on the subject of Heath's inven tion. The writer of that letter says, "I am a steel-maker, and deny that steel was ever made with the addition of carbon and manganese, or carburet of manganese, pre viously to Heath's invention, and I confidently assert that; no cast-steel maker can now carry on his business to profit without the aid of carburet of manganese." " There are," he says, "a hundred methods of improving steel with manganese, but they all involve the same principle. Put carbon and manganese into the steel-pot in any form you please and at any time you like, and, if the steel be thoroughly melted, the carburet of manganese melts also and is alloyed, and the improvement is unerringly effected, and by the use, in every instance, of carburet of manganese." "At the suggestion of the author, a works for the production of manganese alloys was erected by Mr. Henderson, at Glasgow, who now makes a very pure alloy of iron and manganese, containing from twenty-five to thirty per cent. of the latter metal, and possessing many advantages over spiegeleisen, which it will doubtless replace. Two bright rods of 18 inch diameter will be found on the table: they were folded up cold under the hammer. This extremely tough metal is made by using Mr. Henderson's alloy in lieu of spiegeleisen, which is incapable of making steel of such a quality.