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ica the furnaces usually contain from continually. If this is not done the refour to ten holes, six pots being placed sult will be a defective ingot. in each, three abreast and two deep. The T he pots, if in good conditior., are repots rest upon a thick layer of coke dust, filled, and placed back in the furnace. which is able to withstand a very severe When the steel in the moulds has solidiheat without becoming spongy or liquid, fied, the moulds are unfastened and the the coke dust making a very firm yet easy hot ingots drawn out, ready for another rest for the pots. Each hole is provided department. with three covers, which are easily removed by means of a lever.
Handling of Crucible Steel The furnace being thus charged, and The ingots are first taken from the the covers placed over the holes as closely casting pit or furnace to the "tempering" as possible, the gas and air are permitted department. Here, by means of a sledge, to enter. Rushing through the super- the top or piped end of each ingot is heated chambers on one side of the row knocked off in order to expose the grain of holes, they meet and pass through the of the steel, thus permitting an experiflues into the furnace.
enced eye to ascertain the carbon perDarting around the pots, this heated centage of the same. In mild ingots, gas, which rises in temperature to about and those of a shape or size that will not 3,000" F., finally passes through the op- permit of the ends being removed, a posite flues into the chambers on the op- small corner of the ingot is chipped off. posite side. Circulating through these The formula being marked upon the and thoroughly heating the same, it ingot, indicating the grade and the perfinally passes up the stack.
centage of carbon, the ingot is then either The pots are subjected to this terrific piled in stock or taken directly to another heat for two and a-half to three hours, : department. Unlike the products of when the melter, by means of an iron other processes, many grades of crucible rod, pushes the caps of the pots aside to steel are first welded-hammered at a ascertain whether the mass is melted. high heat—thus refining the grain and When melted it is still left in the furnace, destroying many of the blow holes or in order to boil out any gas which might gas holes. The steel is then usually taken be held in solution. This is termed “kill- directly, either to the hammer shop or to ing" or "dead melting." Having been the mills. In either case the billets are “killed,” the molten steel is ready to be reduced to the desired shape and size by cast.
being passed between rolls or under the
rapidly moving dies of the steam hamHow the Workmen Make Ready
mers. The completed billets go to the
"inspection house,” where every bar of In preparation for this work of cast- steel is examined minutely for all defects ing, the men wrap their legs with carpets, before being weighed, marked, and rubber, etc., and soak themselves with shipped. water. The cover is drawn from one of the holes ; and the "puller out,” dressed
The Open Hearth Process as above described, stands over the fur- The open hearth process furnishes nace or hole, and by means of a pair of about one-third of the steel used to-day. tongs pulls the pots out, one at a time, It has, for the past few years, been carrying them to the moulds, which are rapidly crowding Bessemer steel out of standing in the casting pit at the end of the market, as well as making great inthe floor. There the molten steel is roads in the fields formerly occupied by poured into the moulds, which stand up- the crucible product. right. As a rule, the moulds are of one- The cause of this popularity, on the pot capacity ; but, if larger ingots are de- one hand, is that the stock, in many sired, larger moulds are employed, the cases, is much sounder and gives better metal being obtained from several pots. satisfaction than Bessemer—which nat-Care is taken that the stream from the urally justifies the small additional extwo pots is not broken, the liquid flowing pense. On the other hand, experiments
stae Hoof to the mone mould
Thereasting pit.ds, which
FILLING THE BESSEMER CONVERTER WITH WHITE MOLTEN IRON, TAKEN DIRECTLY FROM EITHER THE BLAST FURNACE OR THE CUPOLA.
A PIECE OF WHITE-HOT STEEL, WEIGHING 6,000 POUNDS, ENTERING THE ROLLS. RAISING A WHITE-HOT PIECE OF STEEL FROM THE SOAKING PITS BY MEANS OF A POWERFUL
ELECTRIC ARM. This giant hydraulic crane, clutching in its jaws the white-hot ingot of steel, well illustrates the titanic apparatus used in great steel mills. In comparison with the enormous weights to be lifted and the tremendous heat to be dealt with, man is so pupy that, of necessity, almost everything must be done by machinery, human fingers being neces
sary chiefly to raise and lower the lovers and press the buttons which set tbe great machines in motion.