METALLURGY. 



575 



may suffice. Toward the end of the opera- 

 tion, and while the steel is being tapped out 

 of the converter, the blast is admitted very 

 slowly, to avoid " overblowing," and a hole is 

 provided in the shell of the converter at such 

 a height that the slag runs out through it dur- 

 ing the converting operation. These changes, 

 though they seem to be only mechanical modi- 

 fications of the Bessemer process, have an im- 

 portant bearing upon the steel produced ; for 

 they cause, by the rapid oxidation of the iron, 

 the almost entire elimination of the silicon. 

 But the phosphorus is not removed, and its 

 percentage is rather increased through the loss 

 of metal in conversion. Yet this phosphoric 

 steel is surprisingly ductile. The cost of con- 

 version by this process is estimated at from $3 

 to $4 a ton, at blast-furnaces, and about $6 a 

 ton at rolling-mills. The cost of erecting the 

 plant is small as compared with that of other 

 processas; the steel is rolled with facility; the 

 process permits the production of a high grade 

 of steel from a cheap grade of pig-iron ; and 

 the operation of the plant does not require 

 skilled labor. 



The basic or Gilchrist-Thomas process for 

 making steel (see "Annual Cyclopaedia," 1832), 

 has come into very extensive use on the Con- 

 tinent of Europe, where nearly one thousand 

 tons of steal are made by it per week; and 

 it is also beginning to make way in England. 

 A number of important principles and details 

 to be obsarved in manipulation have been es- 

 tablished by experiment in its practical appli- 

 cation. In order to make good steel by it, it 

 has been found necessary to have in the ma- 

 terial used from 1 to 2 per cent, of phosphorus. 

 If more than the larger quantity is present, too 

 much iron is lost in effecting its removal ; if 

 less than the smaller quantity, the difficulties 

 of operation become too great for the method 

 to be profitable. There should also be not 

 more than from 0'5 to T8 per cent, of silicon; 

 and, as a rule, the less of this substance the 

 better. The basic substances used for the re- 

 fractory materials of the apparatus are shrunk 

 dolomite for the lining, and magnesia, magne- 

 site, bauxite, and chrome-iron for the points 

 of contact between the basic materials of the 

 hearth and the acid bricks of the roof. The 

 outside of the furnace presents few novel feat- 

 ures, bat modifications of its interior are re- 

 quired on account of the high quality and price 

 of the refractory materials, and of the chemi- 

 cal changes that are likely to take place be- 

 tween a roof which is necessarily acid and a 

 hearth which must be basic. The roof must be 

 separated from the hearth, both on account of 

 these chemical changes, and to facilitate re- 

 pairs. Roofs have been built of shrunk dolo- 

 mite bricks and of magnesite, but they have 

 not stood as well as the acid roofs of silica 

 bricks provided the junction between the ba- 

 sic and acid material has been properly made. 

 The process produces a high quality of steel, 

 which, when properly worked, will contain 



from 0-02 to 0'04 per cent, of phosphorus, from 

 0-01 to 0-03 per cent, of sulphur, and from 

 none to 0*004 per cent, of silicon, with carbon 

 varying from 0-06 to 0*45 per cent., from a ma- 

 terial almost useless for any other process. No 

 other process, it is said, can deal so well with 

 pig and scrap iron containing irregular quanti- 

 ties of phosphorus and silica. About the same 

 labor is required as in other processes ; the 

 output is equal to that of the acid process, and 

 the results are just as certain, but the labor is 

 more difficult, and the cost of the refractory 

 materials and of repairs is greater. 



Mr. Joseph Beasley has invented a new de- 

 phosphorizing process which may be econom- 

 ically and effectively employed in puddling- 

 furnaces. Its essential feature is the use of a 

 peculiar fettling, which is composed of one 

 third of calcined tap-cinder (or " bull-dog," as 

 it is termed) and two thirds of ore (or u Blue 

 Billy "), ground to the condition of sand. This, 

 mixed with 5 per cent, of dilute hydrochloric 

 acid, is allowed to stand for three or four days, 

 with frequent turning and incorporating ; and 

 to it are added shortly before use common salt 

 and ground lime in quantities proportioned to 

 the amount of pig to be puddled usually from 

 20 to 30 per cent. These ingredients are thor- 

 oughly commingled, made into a stiff paste 

 with water, and plastered over the ore or 

 "bull-dog," which is placed around the fur- 

 nace-bottom. Over this are thrown a few 

 shovelfuls of a mixture composed of ground 

 ore and ground hammer-slag, saturated with 

 hydrochloric acid, prepared similarly to the 

 first compound, to which lime and salt are also 

 added. A dose of oxide of iron is administered 

 toward the close of the puddling process. With 

 this process the amount of iron obtained is 

 from 5 to 10 per cent, more than by the old 

 process; the metal is free from red -shortness, 

 shows a highly fibrous fracture equal to that of 

 the best-marked bars, and has a tensile strength 

 of about 24 tons per square inch. By it the 

 poorest pig can be worked up into first-class 

 iron. 



A process devised by Dr. Eames, for the pro- 

 duction of iron directly from the ore without 

 melting, has been put into successful experi- 

 mental operation at Sing Sing, N. Y. It con- 

 sists essentially in reducing iron-ore in a com- 

 mon reverberatory furnace, by mixing it with 

 from 15 to 20 per cent, of impure graphite, 

 and subjecting the charge say of 500 pounds 

 of ore and 100 pounds of graphite to a mod- 

 erate heat for 2| hours. The heat is not suffi- 

 cient to fuse the silicious gangue of the ore, 

 or to reduce phosphorus; and the iron sponge 

 is fully protected from oxidation by the carbon 

 of the graphite. 



It is known that wrought-iron or steel bars, 

 after being first heated and then suddenly 

 cooled, become shorter; cast-iron, on the other 

 hand, increases in length, and copper behaves 

 in a similar manner. Mr. Edmund Wehrenfen- 

 nig has made experiments to determine the 



