MX. HIM m:\\\ IN<; \M> 



rolling or hamm.-rini:, but bi-\-ond iliat 

 process diminishes th*- -nvn^th ,,f tin- iron. 



'I'll.' process of piling and rolling ^i\cs wrought it 

 till ro us Sinn-tun-. When subj.-.-ted to vibrat ion- for a Ion;; 

 Hie stru.- (u re becomes crystalline and tin- iron brittle. 

 Th- crystalline structure induced in this way may be removed 

 by the process Of A hich consists in heat IML; tkl 



in a furnace, and then allowing it to cool slowly. 



Tin- process of ]>i. ham 



- wrought inin wlim at a red OT \\hit-- h.-at int 

 desired shaj.r is .-allrd/: i a white heat two pieoei 



light iron be brought together, their surf a g clean, 



le pressed or haiuinered together, so as to form <>n. 

 piece. This is call* ; . \(i\ \ .lual.1. property 



"f \vn.u.irht iron. 



Steel. This is a compound of iron with a small percentage 

 of carbon, and is made either by adding -arln t" wrought 

 iron, or by removing some of the carlxm tn.m east iron 



In the cementation process, bars of wrought iron an- im 

 bedded in powdered charcoal in a fireclay trough, and kept 

 at a high temperature in a furnace for several days. Tin 

 iron combines with a portion of th< carbon to form 

 steel, so named because of tin- blisters which are found on 

 the surface of the bars when they are removed from the 

 farnaoe. 



The bars of blister steel are broken into pieces about 1 s 

 inches long, and tied together in bundles by strong steel wire. 

 These bundles are raised to a welding heat in a furna< 

 then hammered or rolled into bars of shear stf /. 



To form cast steel the bars of blister steel an broken into 

 pieces and melted into cruci' 



In th fl !/"/viw process for making steel, cast and 



wrought iron are melted together on the hearth of a regenera- 

 tive gas-furnace. 



Bessemer steel is made by pouring melted cast iron into a 

 vessel called a converter, through win. 1 1 i blaci "t air i> tli.n 

 urged. By this means the carbon is burned out, and compara- 

 tively pure iron remains. To tin 



