TILTING OF ^TEEL. 



The ore from which the crude iron to be converted into fteel 

 is obtained, is of ii good iciiid ; it is black, friable, and com- 

 pofed of many fmall grains : it produces very tough iron. 

 The converfion into ilecl is made upon a forge-hearth, 

 fomething fmaller than tliat commonly ufed for converting 

 caft-iron into malleable iron : the fides and bottom are made 

 of caft-iron ; the tuire is placed with very little inclination 

 on one of the fide-plates ; the breadth of the fire-place is 

 fourteen inches, its length is greater ; the lower part of the 

 tuire is fix inches snd a half above the bottom : in the inte- 

 rior part of the fire-place, tliere is an oblong opening for 

 the flowing of the fupcrfluous fcoria. 



The workmen firft put fcoria on the bottom, then char- 

 coal and powder of charcoal, and upon thefe tlie cail-iron, 

 run or cut into fmall pieces. They cover the iron with more 

 charcoal, and excite the fire. When the pieces of iron are of 

 a red white, and before they begin to melt, they Hop the 

 bellows, and carry the mafs under a large hammer, where 

 they break it into pieces of three or four pounds each : 

 the pieces are again brought to the hearth, and laid within 

 reach of the workman, who plunges fome of them into the 

 fire and covers them with coal. The bellows are made to 

 blow flowly till the iron is liquefied, when the fire is increafed; 

 and when the fufion has been long enough continued, the 

 fcoria is allowed to flow out, and at that time the iron 

 hardens. The workman adds more of the piece of crude 

 iron, which he treats in the fame manner, and fo on a third 

 and fourth time, till he obtains a mafs of fl:eel of about a 

 hundred pounds, which is generally done in about four 

 hours. This mafs is carried to the hammer, where it is 

 forged and cut into four pieces, which are further beat into 

 fquare bars four or five feet long. When the fteel is thus 

 forged, it is thrown into water, that it may be eafily broken, 

 for it is yet crude and coarfe-grained. The fteel is then 

 broken in pieces, and carried to another hearth, fimilar 

 to the former. Thefe pieces are laid regularly in the 

 fire-place, firft two parallel, upon which feven or eight 

 others are placed acrofs ; then a third row acrofs the fe- 

 cond in fuch a manner, that there is a fpace left between 

 thofe of the fame row : the whole is then covered with 

 charcoal, and the fire is excited. In about half or 

 three quarters of an hour the pieces are made hot enough, 

 and are then taken from the fire one by one, to the 

 hammer, to be forged into little bars from half a foot to 

 two feet long, and while hot, are thrown into water to 

 be hardened. Of thefe pieces, fixteen or twenty are put 

 together, fo as to make a bundle, which is heated and 

 welded, and afterwards forged into bars four inches 

 thick, which are then broken into pieces of convenient 

 length for ufe. 



Converting of Steel by Cementation with Charcoal. — The 

 quality of Iteel is intimately connefted with that of the iron 

 from which it is converted, and the iron made in Sweden is 

 efteemed the beft for the purpofes of cementation. This 

 , procefs is almoft wholly in the hands of the Englifti, who 

 pay a higher price for the iron, and by that means fecure 

 nearly all the iron of Roflagia, which is the beft iron of 

 Sweden. 



The beft marks of Swedifli iron are : that called the hoop 

 L, which is denoted by a circle, with an L in the centre ; 



S, f (p) : and the gridiron, 



;ithus, {CL)) • t'^e G L ; thus, ((. j : the double bullets ; 



thus, ^jp\. The iron of thefe three marks bears nearly the 

 fame price, which is fometimes as high as 40/. /.";• ton. 

 "There are alfo the Swedilh mai-ks ; as P L, (p /} : the hoop 



which are worth a 



few pounds /iir ton lefs than the former ; viz. from 34/. to 

 3S/., when the beft marks are 40/. 



The Ruftian marks are, firlt, that called the C C N D : the 

 mark is fix Ruffian letters, C H E H P B, worth about 

 37/. per ton, when the others are at 4c/.: and the P S I, 

 which is marked by the Ruffian letters P S I, is fo inferior, 

 as to fell for only 26/. or 27/. 



It is to be lamented that, in the prefent ftate of our 

 iron manufadlurc, we are unable to produce malleable 

 iron which is equally fit for converting into fteel with 

 the Ruffian and Swediih iron. The general opinion upon 

 this deficiency is, that it arifes from fome fuperiority 

 in the foreign ores of iron, but more immediately from 

 the circumftance of their ufing charcoal of wood inftead 

 of the coke of pit-coal in fmehing or reviving them ; 

 and fume of our manufatturers do not hefitate to aflert, 

 that tlicy can make iron with charcoal equal to the foreign 

 in quality ; but that in refpecl to price, the circumftances 

 of this country will not allow them to cope with thofe 

 countries, where the deftruftion of wood is in fome mea- 

 fure confidered as beneficial, by clearing the land for the 

 operations of huft)andry. 



The Swedidi and Ruffian iron is imported into this 

 country by iron merchants in immenfe quantities to- 

 gether, this trade being in the hands of a few in- 

 dividuals : by them it is retailed in fmaller portions to 

 the converters, whofe furnaces are chiefly about Sheffield 

 and at Newcaftle, who, after cementation, difpofe of the 

 greater part of it to the manufafturcrs of fteel goods in 

 the ftate of bliftered bars. Its value is eftimated by the 

 Swedifli or Ruffian marks of iron, whicli ttill remain upon 

 the bars. The manufafturcrs fend their bars to the tilt- 

 mills, where they are made into common fteel and fliear or 

 German fteel, or they melt it to form caft-fteel. 



The converfion of iron into fteel is performed in a fur- 1 

 nace, hence called a converting furnace. The external build- 

 ing is a large .ind tall cone, fimilar to a glafs-houfe, within 

 which, one or two large crucibles, called pots, are placed, 

 and furrounded by flues in a manner beft calculated to com- 

 municate a conftant and regular heat to every part of them. 

 In thefe pots the iron bars are placed, being ftratified in 

 pulverized cliarcoal, and the pots are covered over with 

 fand to exclude the external air. 



A more perfeft idea of the converting furnace will be 

 had by referring to Plate VII. of Iron Manufadure, which 

 contains a horizontal plan and two vertical feftions of one of 

 the furnaces ufed in the neighbourhood of Sheffield, with two 

 pots for containing the iron. In all the figures, the fame 

 letters of reference denote the fame parts. C C is the exter- 

 nal cone, built of brick or ftone work ; its diameter at the 

 bafe varies in diff^erent furnaces, according to the fize of the 

 pots it contains : its extreme height from the ground to its 

 vertex fliould not be lefs than forty or fifty feet to caufe a 

 proper draught. To create a fufficient heat for the procefs, 

 the top of the cone ufually terminates with a cyhndric 

 chimney of fome feet in height. The conical form of the 

 external building is by no means eflential ; any form will 

 operate in the fame manner, if it is of a proper height : fome 

 are in praftice built nearly in the fliape of the fmall end of 

 ^" '^gg> w't^b a round chimney upon the top. The lower 

 part of the cone is built fquare or oftangular, as is the plan 

 oi Jig. 3. The fides are carried up until they meet the 

 cone, giving the furnace the appearance of a cone cut to a 

 fquare or oftangular prifm at its bafe, and exhibiting the 

 parabola where every fide interfefts the cone. 



The coiiical building contains within it a fmaller furnace, 



called 



