THE 



ANNUAL OF SCIENTIFIC DISCOVERY, 



mecha:n"ics aintd useful aets. 



MECHANICAL PROPERTIES OF IRON AND STEEL. 



Bessemer has effected a revolution in the manufacture of iron 

 and steel ; and the present improvements exhibit a means of de- 

 velopment b}^ which the former will ultimately double its strength, 

 and in the state of steel be substituted for purposes of construc- 

 tion. The result of this change, when applied to structural pur- 

 poses, is considerable, as half the weight of steel is equal in 

 strength, and consequently is cheaper than a given weight of iron. 

 In almost every case where iron is at present used steel would then 

 be employed ; it only requires certainty and uniformity of character 

 in its manufacture, to insure its superiority and extend its appli- 

 cation. This has not as yet been accomplished ; but the Bessemer 

 jDrocess, by dej^riving the crude metal of its carbon in a separate 

 vessel, certainly tends in that direction; for by this process in- 

 creased facilities are not only afforded and new combinations 

 formed, but the introduction of measured quantities of the same 

 metal, containing the requisite quantity of carbon, poured into 

 the converting vessel, appears to be the only true principle on 

 which steel, in its varied conditions of ductility, tenacity, etc., can 

 be jDroduced. These quantities, when duly proportioned, indicate 

 the quality of the steel to be obtained from this process, and when 

 cast into ingots are ready either for the forge or the rolling-mill. 

 From this it will be seen that every description of homogeneous 

 iron or steel may be produced, care being taken to ascertain the 

 exact percentage of carbon requisite to be infused in order to 

 combine with the mass of refined metal. 



The old method employed in the converting furnace, with the 

 bars embedded in charcoal, required at least a fortnight for the re- 

 fined iron to absorb the necessary quantity of carbon to form 

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