90X ManufaRui^t tf Call ZieeK 



11. 



InJlruB'ions concerning the ManufaElure of Steel, and its Vfes. By VaSDERMONDE-, Monge, 

 and BeRTHOLLET. Publijhed by Order of the Committee of Public Safety. 



[Concluded from VoL ii. p. 70.] 



c 



Of Cajl Steel. 



AST Steel is produced by fufion of natural fteel, particularly that of cementation. 

 The fluid ftate aflumed by the metal in this operation caufes the flaws and veins to difap- 

 pear, and renders the whole mafs more uniform. 



According to the defcription which Jars has given us of the manner in which this ope- 

 ration is performed at Sheffield, all kinds of fragments of broken fteel are ufed. The fur- 

 nace is of the fame kind as that of the brafs-founder, but much fmaller, and fupplied with' 

 air by a fubterraneous communication. At the mouth of the furnace, which is fquare, 

 and level with the earth, there is an opening againft a wall where a chimney is carried up. 

 Thefe furnaces contain only one large crucible nine or ten inches high, and fix or feven in 

 diameter. The fteel is put into the crucible with a flux, the compofition of which is kept 

 fecret : and the crucible itfelf is placed on a round brick ftanding on the grate. Coak is 

 placed round the crucible, and the upper part of the furnace is filled with it. It is then 

 fet on fire ; and the upper opening of the furnace is entirely clofed by a covering formed 

 of bricks, bound together with iron. 



The crucible remains five hours in the furnaCc before the fteel is perfe£liy fufed. Se- 

 veral operations are afterwards made. Moulds formed of two pieces of caft iron, which 

 fit together, and form an odtagonal or fquare cavity, are prepared for cafting the fteel, 

 which is afterwards hammered out in the fame manner as blifter-fteel, but with lefs heat 

 and more care, becaufe of the danger of breaking it. 



Chalut, officer of artillery, has made, experiments on the flux which is beft adapted for 

 making caft fteel. He is convinced that every kind of glafs may be ufed as a flux, except 

 that which contains lead or arfenic. 



The fteel being broken into fmall pieces, is to be covered with the glafs. The cover of 

 the crucible muft then be put on, and the heat urged to the greateft degree of the brafs- 

 founders furnace. 



It appears that an extraordinary hardnefs is fometimes required to be given to caft fteel, 

 and that this efl^e£l; is produced by mixing coaly matter with the flux, to faturate the fteel, 

 and give it the higheft degree of hardnefs. It is probable that certain inftruments are ma- 

 nufaftured by fome procefs of this kind ; fuch as cylinders and laminating rollers, of which 

 the hardnefs is very great, and the grain perfeflly uniform through the whole mafs : — but 

 on this fubjeft we have nothing to offer but conjeftures. 



One of the greateft difficulties we find in this country (France) in the fufion of fteel, is 

 to procure good crucibles. The art of pottery, which is truly important in every one of its 

 parts, is that which, of all others, the moft flrongly folicits our induftry. 



6 Con- 



