530 



METALLURGY. 



the elastic limit nearly double that of cast-steel. 

 The blades, therefore, can be made of it much 

 thinner and lighter than of steel and gun-met- 

 al. The blades, when cast, come out of the 

 sand true and smooth, and, as they do not have 

 to be annealed, are wholly free from the distor- 

 tion to which steel blades are liable in passing 

 through that process, and which, inducing a 

 variation from the theoretical form, causes in 

 them a serious waste of power. This metal is 

 also free from the liability to pitting and cor- 

 rosion, for which allowance has to be made 

 in all steel propellers by giving them greater 

 thickness than is necessary for strength, and 

 thereby increasing the resistance; and it is 

 practically incorrodible. Other practical ad- 

 vantages which may arise from the use of this 

 substance are the reduction in weight effected 

 by its use, with a corresponding reduction in 

 the stem-frame of the vessel in a heavy sea; 

 and facility of restoring the shape of the blades 

 if they are bent, and of replacing them if they 

 are broken. The drawback lies in the cost of 

 manganese bronze, which is about twice, for 

 the same weights, that of steel ; but the friends 

 of the use of this metal assume that this will be 

 more than offset by the reduced quantity of 

 the metal that will have to be employed, and 

 in the practical indestructibility of the manga- 

 nese bronze. Steel propellers require to be 

 renewed every few years; those of manganese 

 bronze, it is claimed, will last the lifetime of 

 the vessel. 



Dr. G. Durgee, of New York, has invented 

 a process for manufacturing iron direct from 

 the ore by the aid of crude petroleum as fuel, 

 in a special revolving furnace. It employs 

 two furnaces, which are placed at slightly dif- 

 ferent levels, with a total length of 120 feet, 

 the working capacity of which is a hundred 

 tons of ore in twenty-four hours. The ores 

 are pulverized and then submitted to the ac- 

 tion of an oxyhydrogen-flame produced by a 

 blast of air with petroleum and coal-dust. The 

 first experiments with this process were re- 

 ported to be successful and encouraging; but 

 late statements of its working have not been 

 published. 



DEPHOSPHOKIZ ATION IN IKON-SMELTING. The 

 Gilchrist-Thomas, or basic, process for the de- 

 phosphorization of iron in working the ore de- 

 pends for its efficacy upon the power of lime 

 to absorb phosphoric acid. When it is used in 

 connection with the Bessemer process, the Bes- 

 semer vessel is lined with magnesium lime, 

 which has been previously subjected to an in- 

 tense white heat, and so brought to a condi- 

 tion of density, tenacity, and hardness in 

 which it resembles granite or flint more closely 

 than ordinary well-burned lime, in which con- 

 dition it is known as "shrunk lime." Before 

 the metal is run into the converter, from 15 

 to 18 per cent of its weight of common 

 well-burned lime is thrown into the ves- 

 sel. The metal is then introduced and the 

 charge is blown in the ordinary way to the 



point at which the ordinary Bessemer opera- 

 tion is stopped that is, till the disappearance 

 of the carbon, as indicated by the drop of the 

 flame. The dephosphorizing process requires, 

 however, to be continued for from one hun- 

 dred to three hundred seconds longer, during 

 which the great bulk of the phosphorus is 

 removed. Not only is the phosphorus re- 

 moved by this operation, but the silicon also, 

 of which inconvenient and even dangerous 

 quantities are occasionally left in the Bessemer 

 process, is entirely eliminated, while at least 

 60 per cent of any sulphur, also untouched in 

 the ordinary process, which may have been 

 present in the pig, is also expelled. The phos- 

 phorus is, in fact, made a real assistance in 

 the perfection of the process, through the in- 

 tense heat it affords by its combustion. The 

 substantial position occupied by the basic pro- 

 cess is well shown by the large amount of 

 basic steel which was turned out in October, 

 1882. Germany held the first position, with 

 an output of 25,170 tons by eight firms ; Eng- 

 land stood next, with an output of 7,700 tons 

 by one firm ; then followed Austria, with 7,700 

 tons by three firms; Belgium, with 1,687 tons 

 by one firm ; Russia, with 1,270 tons by one 

 firm; and France, with 1,240 tons by one 

 firm giving a total output for the month of 

 46,537 tons, by fifteen firms. The process had 

 been adopted at the end of 1882 by thirty-two 

 European firms, which had working furnaces, 

 or were constructing them, and thirteen other 

 firms had taken out licenses for its use. 



IMPKOVEMENTB IN STEEL-MAKING. A new 

 process in rolling steel, called the "Soaking 

 Pit Process," has been introduced by Mr. John 

 Gjess, of Middlesbrough, by means of which 

 the bloom may be rolled into a rail or other 

 finished article with its own initial heat, and 

 the necessity of submitting the ingot again to 

 the heating-furnace is avoided. The chief dif- 

 ficulty heretofore met in utilizing the heat of 

 the ingot, to work it up into the finished prod- 

 uct, has been that the bar when newly stripped 

 was too hot in the interior to be rolled, and 

 when the interior was in a fit condition, the 

 exterior was far too cold. In the new process, 

 the ingots are placed in pits, where little or no 

 heat being able to escape to the surface, and 

 the ingots being surrounded by walls as hot as 

 themselves, the surface heat of each one of 

 them is greatly increased, and it becomes fit 

 for the rolling-mill in about half an hour. The 

 process was introduced in June, 1883, at the 

 Darlington Steel and Iron Company's works, 

 where three hundred ingots were treated in 

 the pits every twenty-four hours, and at the 

 West Cumberland Steel Works; and more 

 than 30.000 tons of ingots had been success- 

 fully treated by the close of the year at each 

 place. The economical advantages of the pro- 

 cess are obvious. The steel manufactured by it, 

 whether for rails or wire billets, is thought to 

 be improved by it, for the danger of burning, 

 to which all reheated steel is liable, and which 



