STKKL. 



STEEL MANUFACTHiK. 



820 



Camphor U the must remarkable substance of the class of stearoptens. 

 It is obtained by distillation with water, and in the plant is mixed 

 with camphor-oil, from the gradual oxidation of which it appears to 

 be produced. [ESSENTIAL OILS.] 



STKKL. [METALS, Iran.] 



STKKL KNuliAVJXO. [KXOHAVISO.] 



s 1 Kill. M AM K.UTURK. Iron possesses qualities which render 

 it applicable to innumerable purpose* in the arts; but there are 

 some uses for which it is not sufficiently hard, and this defect is 

 supplied by converting it into steel. 



At Eiaenarzt in Styria the manufacture of steel has been carried on 

 ever since the 8th century, and yet the exact nature of the operation 

 is perhaps even now imperfectly understood. It is generally admitted 

 that steel U an intimate compound of iron and charcoal ; for soft iron 

 contains a considerable jxirtion of charcoal, and it U by no means clear 

 that the quantity is in. -rented in the process of steel-making. There- 

 fore we must conclude that some more intimate union is effected 

 between them when iron is converted into steel. On this point we 

 <li.il! touch again after describing the manufacture. 



Hitherto Swedish and Russian bar-iron have been almost exclusively 

 employed in the manufacture of the best steel ; the preference given to 

 this iron is decided, though from what cause it arises has not been 

 satisfactorily made out. We may, however, remark that the foreign 

 iion u*ed in made from magnetic iron-ore with charcoal; while 

 irn is obtained mostly from the impure carbonate of iron, called 

 argillaceous iron-ore, or from ha'tnatite, which is a peroxide of iron, 

 ami Uith of these are reduced by employing coal, or coke prepared 

 from it. 



Jiar-Steel is made, with few exceptions, from the Swedish and 

 Russian iron, the bars of which ore marked hoop I (\), gl (2), and 

 double bullet (3) ; these are the .best kinds. Iron of lower quality is 

 also used, such as (4), which is a Russian iron, and c and crown (5), 

 il and <TOK> (6), which are Swedish irons. There is a medium quality, 

 namely, and crotcm (7), ft and crotni (8); these also are Swedish. 



mm vwuu m 

 C D W B 



1 a 4 5678 



These steel irons are imported almost exclusively by English merchant* 

 residing in Hull. The limited quantity of the fine iron allowed to be 

 produced from the mines of Danemora in Sweden accounts in some 

 degree for the high price at which they are sold. 



Mar-Sleel. The usual operation in large steel-works is first to cut 

 the bar-iron into certain lengths. The closed vessels in which the 

 ban are heated are usually twelve feet in length, and divided into two 

 cells or troughs, on the bottom of which the workman strews charcoal 

 to the thickness of about an inch. Upon this he places on their flat 

 side a layer of bars; then about three-fourths of an inch more of 

 charcoal is added ; on this another layer of bars ; and so on till the 

 troughs ore filled. These are then covered with a ferruginous earth 

 coming from the grinding-stones, called wheelswarf, to the thick- 

 ness of about eight inches. All the apertures of the furnace are 

 closed with loose bricks and plastered over with fire-clay. The fire is 

 thru lighted, and in four days and nights the furnace is at its full he it; 

 at which it is kept for several days, according to the degree of hardness 

 required. In order to be able to test the progress of the carbonisation, 

 a hole is left in one of the troughs near the centre ; three or four bars 

 are placed in the furnace in such a manner that the ends come through 

 this opening, and after the sixth day one is pulled out. If the iron be 

 then not sufficiently carbonised, the heating is continued from two to 

 four i Lays longer. A bar is drawn every two days ; ami when the iron 

 is completely converted, the fire is heaped up with small-coal, and the 

 furnace is left to burn out. It requires from this period fourteen days' 

 tinii- to cool sufficiently to allow a person to go in and discharge the 

 Hteel. The cells or troughs must be kept completely air-tight; the 

 -t crack will open when the furnace is hot, and admit the air : 

 ti,i* of course frustrates the object of the operation, and .11 

 which has thus suffered is placed aside to be reconverted. It is of the 

 greatest importance to give the iron the exact quantity of carbon 

 required and no more. For coach-springs, the iron must not be con- 

 verted to the centre. For common cutlery, sheer steel, and for pur- 

 poses where steel has to be welded to itself or to iron, the con 

 xhould be low, and gradually disseminated throughout the whole 

 thickness of the lur. For double sheer steel, tin- Oonvei i.nj should be 

 s .in. 'what harder than the preceding. I >d all instruments 



where resistance or fine cutting . lie conversion 



should be hard, and the iron fully carbonised timing-limit the bar. 



No definite rules can be laid down to enable, tin uninitiated to judge 

 of the temper or degree of hardness of a bar of steel; but by habit 

 workmen soon acquire the means of distinnui-hing bet 

 f.T.-nt degrees of hardness of two pieces of steel. Tlii- knowledge of 

 the degree of temper is of great importance to the steel-maker 



ado from soft steel which would be valuable for welding purposes, 

 would be useless in the arU ; while a coach-spring made from steel 

 hard enough to nuke a file could not be applied to its intended 

 purpose. 



-A converting furnace contains generally fifteen tons of iron ; and 

 there are some large enough to hold eighteen to twenty tons. The 

 bar-steel, when discharged from the furnace, is partially covered with 

 small raised rortions of the metal ; and from tlie resemblance of tlioe 

 to blisters, the steel is called -I. It has been found by tin 



sxpstiment of placing a liar of Swedisli and one of Staffordshire bar- 

 iron in the same furnace, that the fonm-r was much blistered, while 

 the latter hod scarcely any blisters larger than a pea. At one t im. it 

 was common for the steel-maker to receive orders for steel in 1 1 I- 

 This arose from a mistaken idea regarding the perfection of the steel ; 

 it being supposed that the more it was blistered, the more it was 

 carbonised, and consequently that its quality was indicated thereby ; 

 now, however, manufacturers are better informed, and steel so blistered 

 is complained of. 



Bar-steel as it comes from the converting furnace is used for v 

 purposes without refining; those part.-; which are free from flav 

 blisters ore broken out and hammered or rolled to the sizes requinil 

 by the manufacturer for files, edge-tools, table knives and forks, coach- 

 springs, and a great variety of common agricultural implement.-. It i.-i 

 also manufactured into what is called sinylc and <('/'/< .>.', 

 this purpose the converted bar is selected of an equable degree of hard- 

 ness, and broken into pieces of about two feet in length ; these are 

 taken to the forge, heated to a full cherry red, and hammer. 

 bars two inches by three-quarters of an inch in thickness; six of these 

 pieces are put together and kept firmly so by a hoop, which is h 

 the end of a handle, thus- 



They are then placed in a hollow fire urged by a soft blast, and i 

 gradually up to a full welding heat, during which the workman covers 

 the surface with clay beaten very fine; this runs over the surface, and 

 to some extent prevents oxidation. When fully heated, they arc 

 placed under the hammer, carefully welded together, and drawn 

 bar of about two inches square at the same heat ; the other cud 

 put into the fire and welded in the same way. This is termed 

 sheer steel It is made double by nicking the bar in the middle and 

 doubling it together, giving a second welding heat, and drawing it out 

 as before to a bar of about two inches square; it is then ham, 

 tilted, or rolled to the size required ; by this process !,,u i - 

 more homogeneous, of a finer texture, and any instrument made oi it 

 will receive and retain a finer edge; the steel is al.-o rendered much 

 tougher, which condition ia supposed to arise from the abstraction of a 

 small portion of carbon, and the mechanical elongation of the fibre by 

 these doublings, &c. 



In Sheffield, where the steel manufacture is carried on to a larger 

 extent thau in any other town in the world, many manufacturing 

 confine their operations exclusively to those above described : namely, 

 making bar steel, in the two forms of blister and titecr, without in- 

 cluding the making of cas(-steel, or the fashioning of steel goods. The 

 sheer-hammers, employed in the production of sheer sf 



machines, having iron heads of twenty cvvts. or more, 

 with steel. The blows of these hammers, acting on heated b 

 steel, greatly change their character ; the blistered steel loses all its 

 blisters and flaws, acquires a uniformity of character throughout, and 

 becomes much more malleable and tenacious. According to the < 

 in which it is welded or sheered, so does the steel become applicable to 

 a large number of practical purposes. 



Coat Steel is the steel employed for the best goods. Cast-steel \v.is 

 first made by Mr. Huntsman, at Atterclilf, near Sheffield, in 177o; 

 since which time the manufacture of it has very much increased. It 

 is steadily superseding the use of bar or sheer steel, on account of the 

 equality of its temper, and the superior quality as well as beauty of 

 the articles which are made of it. The process adopted is that of 

 taking bar steel converted to a certain degree of hardness and In 

 it into pieces of about a pound each ; a crucible charged with thc.-e is 

 placed in the melting-furnace, similar to that used bj brass founders. 

 The furnaces are 2i> inches long by 16 inches wide, and :i feet deep. The 

 most intense heat is kept up for two hours and a half or three hours. 

 coke being used as fuel. When the furnace requires feedin 

 workman takes the opportunity of lifting the lid of each crucible 

 and judging how long the charge will be before it is com) 

 melted. All the crucibles arc usually ready about the same time. 

 They are taken out of the furnace, and the liquid steel is poured into 

 ingots of the shape and size required: the crucibles are i 

 returned into the furnace; and when the contents of all ha\ 

 poured into the moulds, the crucibles are again charged. Tl. 

 used three times, and then rejected as useless. The 

 to the forge-tilt or rolling-mill, and hammered into liars or rolled into 

 sheets, as may be required. The celebrated w.. or Indian steel, is 

 cast-steel ; but it is generally so imperfect as to resemble c:, 

 rather than cast-steel. It is, however, made of iron obtained, as the 

 Swedish is, from the magnetic ore. Woot/ JR made by the natives 

 from malleable iron, packed in small bits with wood in erucibl"s, 

 which are then covered with some I clay : about two 



dozen of these crucibles are packet! in one furnace ; they are eo 

 with fuel, and a blast given for about two hours and a half, which 



