IRON MANUFACTUHK AM) TRADE. 



IRON MANUFACTURE AXD TRADE. 



> one ton of those rough bars is about 23 owt, and the quantity of 

 ol eoasumed in the process it about 17 cwt. 



Fig. 6. Puddling Hollors. 



All the processes of refining, puddling, and blooming, like those of 

 Miii-lt ins, have undergone numerous improvements within the lost 

 few years. KeBning is always needed for making the best iron ; but 

 it ia not so much adopted as formerly for the modiurn kinds. Soine- 

 tiiuej, instead of refining and puddling, a process called boilin;/ ia 

 adopted ; and this practice has of late been greatly extended. Those 

 who ' boil their pigs,' as it is termed, do so under the irapre.-<sion 

 that it obviates some of the waste involved in refining. The Imiling- 

 furuace differs in some particulars from the others. Into it is put 

 a (H.rtion of hammer-slag, then pig-iron, and then fresh coal. The 

 metal U kept almost in a boiling state for half an hour, the pudJler 

 working it about all the time; a cinder or heavy slag falls to tho 

 bottom, anil the gradually thickening iron is worked about into balls. 

 As generally conducted, the melting occupies about half an hour, the 

 boiling half an hour, and the balling an hour. All the manufacturer* 

 admit that refining and puddling produce the best iron ; but they 

 differ in opinion concerning the relative advantages of boiling for the 

 middling and cheiper qualities. Boiling is less in favour in South 

 Wales than in Staffordshire. When the iron has been worked about 

 into balls or blooms, either by refining and puddling, or by boiling, 

 the blooms are, as we have said, shingled, or beaten with a few blows 

 of a heavy hammer ; this is admitted to make the best iron ; but the 

 makers of anterior kinds prefer to use a machine called a squeezer, 

 because it leaves some of the slag in the metal, and thereby increases 

 the quantity. Mr. Brown, of the Oak Farm Ironworks, has recently 

 introduced a machine for this purpose. Three excentric cams work 

 simultaneously ; they are kept rotating in one direction by wheels and 

 pinions, worked by steam power. The convex sides of the cams are 

 grooved and serrated. A bloom of white-hot iron being dropped into 

 the concavity of the upper cam, it is drawn into the centre of motion 

 of the three cams; the convexities approach nearer and nearer, and 

 the serrations squeeze and knead the iron like dough. The slag and 

 impurities are expelled, more or less completely, and fall out of the 

 machine, liy the approximation of the cams, the iron is sent out as a 

 sort of cylinder. ThU may be the best place to notice a plan brought 

 forward by Mr. Maudslay, in 1858, for producing cast-iron possess- 

 ing a degree of toughness almost equal to that of the best wrought 

 iron for the steam-engine manufacture. The plan consists in the 

 employment of an entirely novel furnace, which revolves on an axis 

 inclined about 10 from the perpendicular. The rotation is maintained 

 by a system of gearing and toothed wheels, actuated by steam power. 

 The iron being brought into a molten state in the furnace, and being 

 kept constantly stirred, the two movements of rotation and stirring 

 afford great opportunity for the sulphur and other impurities to 

 escape from the mass and to fly off. The iron becomes semi-puddled ; 

 it retains a sufficient degree of fluidity to be cast into moulds, wliioh 

 fully puddled iron does not ; while it has more fibre and toughness 

 than pig or raw iron. The metal is, in fact, precisely in a medium 

 slate between pig-iron and malleable-iron. 



li'ilied Iron. We shall adopt this as a convenient name for iron in 

 a more advanced state. We have seen that the crude smelted metal 

 constitutes ;'// iron ; that when this is run into moulds it becomes 

 nut-iron ; and that when the pigs have been refined and puddled, or 

 boiled, the result is naUeabU-iron. This malleable iron is the sub- 

 itanco from which are made bars, rails, nail-rods, wire, sheets, &c., 

 all of which we may consider to be varieties of rolled iron, since 

 they all |ss between the nearly touching surfaces of ponderous 

 iron-rollers. 



When the blooms have been shingled or squeezed, and roughly 

 rolled into bars, in the manner already described, and while yet hot, 

 they are cut into convenient lengths and taken to the balliny-ftirnacf, 

 the shape and construction of which resemble the puddling-furnncc. 

 In this balling-furnace the ban are piled evenly, so that one Kir dot-n 

 not project beyond another. Several of these piles, each of which is 

 composed of five or six bars, are placed at once in the furnace, and 

 wheu sufficiently heated, so that they will weld together, the piles are 

 taken out separately and are passed again through rollers similar in 

 construction to those described above, but differing from each other 

 ia the form of their orifices and grooves, so that either round or 

 flat or square rods and bars may be produced at the pleasure of the 



In UM production at various kinds of iron from the malleable state, 



little more is necessary than to vary the roller* through whirli i 

 panes, in their diameter, their power, their closeness, or the size and 

 shape of their grooves. In some of the establishments, the rou 

 rolls, or those first used, are of vast size and weight as much as 

 64 feet long by ''1 inches in diameter, requiring great steam-power to 



I I In 



Fig. 7. Rolling Bar-iron, 



rotate them. Some of the achievements in rolling bare are very 

 remarkable. When the Great Exhibition of 1851 was about 

 held, tlie Rhymncy Works in Monmouthshire produced the ! 

 and heaviest rail ever made, being 52 feet long and weighing 1575 Ibs. 

 Thereupon, the workmen at the Tredegar Works voluntarily under- 

 took, for the honour of their firm and not for pay, to produce 

 larger rail ; then- specimen was 60 feet long, but a few pounds 1 

 than that from Rhymney. The rolling of iron in' ra, and 



rods is very similar in its character, seeing that there are g 

 in the rollers for all these kinds. In producing sheet-iron, ho 

 this is not the case; the rolls are smooth, and the gradual thinning 

 of the sheet results from bringing the rollers more and i 

 into contact. In preparing the sheets for various manufacturing pur- 

 poses, a machine is sometimes used, one end of which cuts the iron as 

 if it were a piece of pasteboard, while the other pierces it for the 

 reception of riveta. 



It is right to mention here, that the rolling of iron was one of tho 

 capital inventions of Richard Cort, who, by a series of scan, 

 actions on the part of a government officer, and laxity in 

 morality generally, was brought to utter min in tin attempt to carry 

 out a system which has greatly enriched the iron manufacturers of 

 this country. The whole case is being minutely narrated by Mr. 

 Webster, the barrister, in a series of papers in the ' Mechanics' Maga- 

 zine ' for 1859 and 1860. 



Projected Improvement!. It is impossible to notice hero all the 

 novelties introduced or proposed in the iron manufacture within tho 

 last few years ; but there are three concerning which a few word.i may 

 be given : namely tho production of iron direct from the ore ; the 

 utilisation of slag; and the utilisation of the gases and heated air of 

 the blast-furnace. The process introduced and wannly advocated by 

 Mr. Bessemer will best be noticed in connection with S 

 FACTUBE. 



The making of wrought-iron direct from the ore is now attracting 

 much attention in the United States. Tin- iron i- in this <,, 

 puddled, as it never melts; but having first be. ed in a close 



chamber, it is simply welded together. Then 1 pro- 



cesses at work to this end. In one, Kenton's, the Mirf.lus heat from 

 the reducing chamber passes round a series of tul.e.-, where the other 

 processes are going on, insomuch that one mass of fuel avails for the 

 whole operation. Another, IJavis's, begins by pulverising tin 

 mixing it with 20 per cent of coal, putting the mixture into an air- 

 chamber heated by anthracite, and thence passing it to a sort of 

 pniMling-furnace heated by the same fuel A thin), Harvey's, employs 

 the gases generated in the furnace to act directly on the 

 dining and desulphurising it, without m.ikiiu; tin ] , c ess a 



distinct one. The ol.ject of all these plans Hcems to be to KU 

 and labour ; but English manufacturers have not yet seen reason to 

 place much reliance on the methods. 



The utilisation of slag is an important matter, if practicable ; for 

 there are millions of tons of it lying waste, all of which is known to 

 contain a certain per-centage of iron. Professor Bleekrode, in a com- 

 munication to the Society of Arts in 1859, drew attention to this 

 matter. Of the vast heaps of slag now existing some are modern, while 

 some are the remains from ancient works. The Swedes make good 



