540 Progress in Science, [Odlober, 



METALLURGY. 



Whilst it is well known that the Russians have long manufactured a thin 

 form of sheet-iron having a beautifully smooth and black surface, the details 

 of the manufacture have not generally been made public. Dr. Percy has 

 recently collected several descriptions of the process, and has published 

 a pamphlet upon the subject.* 



The iron works at which this form of iron is produced are situated on the 

 eastern slope of the Ural mountains. The furnaces are fed with magnetite, 

 red and brown haematite, and carbonate of iron ; these ores being smelted 

 with charcoal. The puddled bars having been cut into certain lengths 

 are heated to redness, and rolled into square sheets. These plates are cleaned 

 with a wet broom of green fir leaves, powdered charcoal is spread between the 

 sheets, and the plates, having been made up into packets of threes, are 

 several times re-heated to redness and passed through the rolls. The sheets 

 are then cut to an uniform size, and brushed over with a mixture of birch- 

 charcoal powder and water. They are then arranged in packets of from 70 to 100 

 sheets each, placed in a re-heating chamber of peculiar construction, and the 

 temperature slowly raised for several hours, whilst oxidation is prevented. The 

 packets having been sufficiently heated are removed and placed under a tilt- 

 hammer. Finished sheets are inserted alternately between the hammered 

 plates, and the packets are then subjected to a second hammering, which 

 removes the wavy appearance resulting from the previous hammering, and 

 produces a smooth surface. The packets being then opened, the sheets 

 are cleaned with a wet broom, and when cool are cut to the standard size, 

 when they are ready for the market. The only secret of the operation by 

 which the beautiful surface is produced, appears to consist in the use of char- 

 coal powder. 



At a recent meeting of the Institute of Mechanical Engineers at Mid- 

 dlesbro'-on-Tees, Mr. I. Lowthian Bell read an able paper, " On the Preli- 

 minary Treatment of the Materials used in the Manufacture of Pig-iron 

 in the Cleveland District." The ore used contains 31 per cent of iron, 

 chiefly as carbonate of protoxide, with 28 per cent of earthy substances. 

 When the ore is roasted in the mine-kiln the water is driven off, a part of the 

 sulphur is expelled, and, if properly performed, the carbonic anhydride 

 is also expelled, whilst peroxide of iron is produced. Two modifications 

 of this process have been suggested: one is to get rid not only of carbonic 

 anhydride and water, but also of the oxygen of the ore before its introduction 

 into the blast-furnace ; and the other is to charge the ironstone just as 

 it comes from the mine. Mr. Bell admitted that the application of any 

 method which would remove from the blast-furnace every trace of carbonic 

 anhydride would cause the process to be less dependent upon the nature 

 of the sources of heat than it is at present ; but he considered that the 

 additional cost of deoxidising the ironstone would be too great to render 

 its adoption profitable. The author also noticed some improvements recently 

 attempted in the manufacture of coke, the object being to increase the per- 

 centage of fixed carbon obtained from a given quantity of coal. The experi- 

 ments had not, however, given successful results. 



At the same meeting Mr. W. Crossley read a paper "On the Manufacture of 

 Iron in the Haematite District." In describing the blast-furnaces used in Fur- 

 ness, he stated that the bell-and-hopper arrangement used for taking off waste 

 gases was not extensively employed in that district, as it was commonly sup- 

 posed to act prejudicially on the quality of the iron, and to throw a heavier 

 back pressure on the furnace — objections which the author does not hold to be 

 valid. Two kinds of haematite are used, one being hard and dry, and 

 employed for producing pig-iron ; whilst the other is soft and damp, and 

 is used for fettling. As the ore is rich in silica and destitute of alumina, 

 it is thought desirable to mix with it some of the Irish aluminous ores in order 

 to produce a good flowing slag. In smelting the ore, it must not be charged 



* The Manufacture of Russian Sheet-Iron. By John Percy, M.D., F.R.S.; London: 

 Murray. 1871. 



