GJERS' SOAKING PITS FOR STEEL INGOTS.
During the soaking operation a quantity of gas exudes from the ingot and fills the pit, thus entirely excluding atmospheric air from entering; this is seen escaping round the lid, and when the lid is removed combustion takes place.
It will be seen by analyses given hereinafter that this gas is entirely composed of hydrogen, nitrogen, and carbonic oxide, so that the ingots soak in a perfectly non-oxidizing medium. Hence loss of steel by oxidation does not take place, and consequently the great loss of yield which always occurs in the ordinary heating furnace is entirely obviated.
The author does not think it necessary to dilate upon the economical advantages of his process, as they are apparent to every practical man connected with the manufacture of steel.
The operation of steel making on a large scale will by this process be very much simplified. It will help to dispense with a large number of men, some of them highly paid, directly and indirectly connected with the heating department; it will do away with costly heating furnaces and gas generators, and their costly maintenance; it will save all the coal used in heating; and what is perhaps of still more importance, it will save the loss in yield of steel; and there will be no more steel spoiled by overheating in the furnaces.
The process has been in operation too short a time to give precise and reliable figures, but it is hoped that by the next meeting of the Institute these will be forthcoming from various quarters.
Referring to the illustrations annexed, Fig. 1 shows sectional elevation, and Fig. 2 plan of a set of eight soaking pits (marked A). These pits are built in a mass of brickwork, B, on a concrete foundation, C; the ingots, D, standing upright in the pits. The pits are lined with firebrick lumps, 6 in. thick, forming an independent lining, E, which at any time can be readily renewed. F is a cast iron plate, made to take in four pits, and dropped loosely within the large plate, G, which surrounds the pits. H is the cover, with a firebrick lining; and I is a false cover of firebrick, 1 in. smaller than the cross section of the pit, put in to rest on the top of the ingot. This false cover need not necessarily be used, but is useful to keep the extreme top of the ingot extra hot. J is the bottom of the pit, composed of broken brick and silver sand, forming a good hard bottom at any desired level.
Figs. 4 and 5 show outline plan of two sets of soaking pits, K K, eight each, placed under a 25 ft. sweep crane, L. This crane, if a good one, could handle any ordinary make--up to 2,000 tons per week, and ought to have hydraulic racking out and swinging round gear. This crane places the ingots into the pits, and, when they are ready, picks them out and swings them round to blooming mill, M. With such a crane, four men and a boy at the handles are able to pass the whole of that make through the pits. The author recommends two sets of pits as shown, although one set of eight pits is quite able to deal with any ordinary output from one Bessemer pit.
In case of an extraordinarily large output, the author recommends a second crane, F, for the purpose of placing the ingots in the pits only, the crane, L, being entirely used for picking the ingots out and swinging them round to the live rollers of the mill. The relative position of the cranes, soaking pits, and blooming mill may of course be variously arranged according to circumstances, and the soaking pits may be arranged in single or more rows, or concentrically with the crane at pleasure.