1871 Iron and Steel Institute: Visits to Works

Note: This is a sub-section of 1871 Iron and Steel Institute

Visits to the Works of South Wales and Monmouthshire

On Tuesday afternoon, the members were conveyed by special train to the Plymouth Iron Works, belonging to Mr. R. Fothergill, M.P. At the Plymouth furnaces the train stopped while its occupants alighted and inspected this portion of the works, where the motive power is water, the blast engine being worked by two large water wheels driven by a feeder from the Taff. From Plymouth the train proceeded to the Pentrebach forges, where the rolling mills were turning out the light rails for Canada, alluded to by Mr. Fox at the morning meeting. The party next proceeded to the Duffryn furnaces, where operations are carried out much upon the same plan as at Plymouth. At this place there is a large engine, the cylinder being 85 inches in diameter, with a stroke of nine feet. It is used for pumping, the water being raised from the pits by three lifts. Several of the members also inspected the fine winding engine erected here.

Thence the members alighted, and walked across the valley to Mr. Crawshay's Castle Pit, where the engine and machinery for pumping, erected upon the plans and designs of Mr. Cope Pearce, were objects of great interest. The cylinder of the pumping engine is 68 inches in diameter.

After inspecting the Castle Pit, the party entered another train in waiting for them, by which they were conveyed to Cyfarthfa works, arriving at the upper portion of the works. The order, arrangement, and convenience of these works evoked expressions of admiration on all sides. Mr. W. Crawshay conducted the party through the works, and the noble President and members generally went over every department of the establishment, examining the chief things pointed out to them as worthy of special notice, with great interest. The numerous stacks of puddled bars, built up with great regularity, and each containing 300 tons of iron, were features of special significance to the practical ironmasters present. By the time Cyfarthfa works had been gone over it was six o'clock, and the proceedings of the day terminated.

On Wednesday afternoon, the members were taken by special train, arranged by Mr. Henshaw, of the Brecon and Merthyr Railway, along the valley of the lesser Taff, in front of the Castle and Works of Cyfarthfa, beneath the ruins of Morlais, and below the bold limestone bluffs that indicate the quarries of those works and of Dowlais. The scenery along the line is exceedingly picturesque.

The Ivor Works were reached about two o'clock, where the party were met by Mr. Clark, under whose guidance and that of Mr. Menelaus, the manager, the party were conducted. The first point of special interest was the puddling forge, in which Mr. Menelaus had endeavoured to solve the question of mechanical puddling, by the adoption of a rotatory vessel in which the iron was treated, but, as will be explained, the process did not prove successful. The puddling apparatus consisted of a horizontal cylindrical vessel, containing about the same cubical area as an ordinary puddling furnace. The size of the bridge end of the vessel is just sufficient to allow a ball of 6 cwts. to pass through. On the bridge end is shrunk a strong wrought iron hoop, 6 in. wide by 2 in. thick, and upon the flue end another wrought iron hoop is fixed. To this hoop is bolted a spur wheel, whereby the vessel is driven. Two trunnions are fixed to each vessel for the purpose of lifting it out of its bearings, and also for tipping it. The forge was intended to contain eight puddling vessels, but only half this number were put up. With the four vessels a number of experiments were tried. The pig iron was run direct from the 'blast furnaces into the converters. The mode in which the puddling process was carried on by this machinery was fully explained. The great difficulty Mr. Menelaus had to encounter was, to find a suitable lining for his converters. Ganister stood well, but made the iron cold short. Titanic ore was also used. It was the difficulty of getting a thoroughly satisfactory lining for the vessels that proved the great obstacle to this system of mechanical puddling.

The members had next an opportunity of witnessing some experiments by Mr. Blair, who was at that time engaged upon the Ellershausen process at Dowlais. Mr. Blair has supplied the following brief description of the Ellershausen process

"The Ellershausen process, in common with most of the methods of transforming cast iron into wrought iron, depends upon bringing the particles of the cast iron into contact with oxides of the same metal. The novelty of the invention lies in the sort of mixture which it produces, and in the manner of obtaining it. The object aimed at is, to introduce throughout the mass of pig iron, granules of oxide, so intermingled that it shall be, in fact, a conglomeration wherein the carburet and the oxide shall be brought into contact so intimate that they shall only require heat to produce the chemical reaction desired. The difficulty—hitherto found insurmountable—in making such a mixture, arises from the great difference in the specific gravity of the heavy molten iron and the comparatively light ore granules. The attempt to mix a quantity of the latter with a mass of the former, has been compared to the stirring of saw-dust into a pail of water, and it would be as hopeless. Mr. Ellershausen, however, discovered that if an attenuated stream of liquid pig iron was struck by a stream of granulated iron ore, there occurred an instantaneous chemical action, converting into the gaseous state enough of the carbon and the oxygen to produce, by their sudden expansion, a refrigeration so active as to cause immediate solidification of the cast iron, thus imprisoning within it, the granules of ore. The first application of this discovery was as follows : A stream of liquid pig iron and one of granulated iron ore, were directed so as to interlock as they fell into an ingot-mould; care being taken that the stream of iron should be kept small enough to prevent the fluid metal from boring into the mass below. Thus the conglomerate was ' built-up' until the mould was full, when it was turned out, as a rough lump, from which the loose surplus ore was readily shaken.

The `pig blooms' — as they were called — thus obtained, were charged into a cinder-bottomed heating furnace, and were, for twenty-four hours, subjected to a heat just below the melting point of cast iron. This part of the treatment produces a cementing' or converting' action, whereby the carbon is so much reduced that the pig blooms do not melt in the after treatment. At the end of the twenty-four hours, the furnace was raised to a white heat and so maintained, until the iron stood up as clean, wrought iron masses which were withdrawn and hammered or squeezed, as balls from a scrapping furnace would be. In order to adapt the principle to work upon a large scale, a mixing machine was arranged, whereby the liquid pig iron is made to fall in a flat stream, into which is projected a similar flat stream of ore grains, so that the two interlock and combine. As they fall, they are received into a revolving mug-shaped trough, which travels with a speed sufficient to cause the deposit to be made in a thin layer, and the continuous flow and continuous revolution build up successive layers, until the trough is filled or the supply of metal exhausted. By this arrangement, an excellent mixture can be obtained, as the quantity of ore injected and the speed of the receiving-trough are both under perfect control. After this machine had been connected with a blast furnace, and pig blooms in large quantities were produced, the after-treatment, as above described, was abandoned, as being too slow, and the pig blooms were charged, cold, into the ordinary puddling furnace and subjected at once to a strong heat. This is the method now practised in America. The pig blooms melt wholly or partially, and after a brief boiling, 'come to nature.' The cinder is tapped off, and the iron at once balled and taken to the hammer or squeezer. Under this treatment, the results obtained are two-fold: the puddler's work is so much diminished that he turns out a largely increased quantity; and the quality of the iron is decidedly improved. The process is being introduced in this country, following the same system, for the present. But it is intended to make a thorough trial of the cementation treatment, using one furnace for the low, and another for the high, heat, and transferring the pig blooms direst from the former to the latter. It is hoped that a furnace receiving the cemented pig bloom at a bright heat will turn out a much greater quantity and of much better iron, than can be had from the same fuel and labour, from the crude pig."

The rolling mill in which the members saw in operation the improved arrangements for rolling rails, described by Mr. Menelaus in his paper, read before the Institute at a previous meeting, was the next point of special interest. The party then proceeded to the Bessemer Steel Department, where, in addition to the general features of such works, the company had recently completed a new cogging machine for rolling down steel ingots. This mill is driven by a pair of 30-inch cylinder engines, without fly-wheel, on Nasmyth's principle, as worked out by Ramsbottom. A pinion, 2 feet diameter on the crank shaft, works into a 9 feet wheel on the main shaft, and this shaft drives the cogging rolls, which are 30 inches diameter, with grooves for reducing an ingot of 14 inches square to about 6.5 inches square. The ingot is passed through the first groove, when the rolls are brought together, as in a plate mill, and the ingot is reduced about one inch in passing back when the mill is reversed; before passing through the next groove the screws are released, and the ingot is passed through edgeways, when the rolls are again brought together, and the proper amount of work put on the ingot in passing back through the second groove. The ingot is worked in this way twice through every groove until it is finished. By this plan a greater amount of work can be done by each groove; and another advantage is, that on one side the ingot requires no handling, the men being all on one side the rolls. The ingots are worked backwards and forwards on both sides of the rolls by a series of rollers, driven by small double-cylinder engines, handled by two small boys. Except when the ingots are turned, they require no handling, and one man and a helper can do any amount of work in rolling. After the ingots are finished to size, they are taken out by a set of rollers to a large saw, where the ingot may be cut to length or cut in half, as required. This saw is a copy of Mr. Ramsbottom's large saw for cutting crank axles. It is intended to use the saw only in exceptional cases. The whole of the machinery has been designed with the object of dispensing, as far as possible, with hand labour. The ingots are moved all through by mechanical means, controlled by small lads, with the exception of turning them on one side of the rolls. The ingot is brought up to the saws by hydraulic power, and when it is finished it is removed by an hydraulic crane. The rolling machinery was designed and made at Dowlais; the mill engines and small engines for working the rollers for moving the ingots were made by the Messrs. Kitson, of Leeds; the hydraulic cranes by Sir William Armstrong.

After a thorough inspection of the works, the members were entertained at luncheon, by Mr. and Mrs. Clark, in the Dowlais Institute.

On Thursday morning, the members left Merthyr by special train for Swansea. They arrived at the Landore Steel Works, where they were met by the Mayor of Swansea (Mr. J. J. Jenkins), Mr. H. Vivian, M.P., and others. Mr. C. W. Siemens and Mr. Gordon conducted the visitors over the works.

The manufacture of steel at the Landore (Siemens) Steel Works is carried on according to the Siemens-Martin process, which consists essentially in the fusion together of wrought iron or steel scrap with cast iron, on the open hearth of a reverberatory furnace, in which an intense heat can be maintained. The Siemens regenerative gas furnaces are employed at these works for the fusion of the materials to be converted into cast steel, and are similar in shape to large heating furnaces; but the upper part is built entirely of special quality of Dinas bricks, in order to resist the intense heat required for the work. There are three doors in the front of each furnace, one in the centre immediately over the tap hole, and two near the bridges' through which the bed can be repaired when necessary, and the melting operations controlled. Two muffles are provided at the back for heating the scrap, previous to its being charged into the bath of molten metal in the furnace. The bottom is formed of silicious sand which is used dry, and is introduced into the furnace in successive layers of about one inch in thickness. The heat of the furnace, which is about that required to weld iron when the first layers are introduced, is gradually raised to a full steel melting heat at the end of the operation, in order to impart solidity to the uppermost layers, and care is taken that the surface of the bath assumes the form of a shallow basin, being deepest near the tap hole. A hard bottom being thus prepared, and the heat of the furnace being raised to whiteness, it is ready to receive the materials to be melted. The capacity of the furnaces is such, that charges of from 4 to 5 tons each can be made. About 8 cwt. of No. 3 hematite pig iron is introduced to form a bath, and iron and steel scrap, first heated almost to the melting point in the back muffles alluded to above, is charged at intervals as it is absorbed in the bath, until the desired quantity, about 4 tons, has been introduced, when, the metal being liquid, from five to eight per cent. of spiegeleisen is charged and allowed to melt down into the bath, which is then stirred and made ready for tapping. The amount of carbon introduced with the spiegeleisen determines the temper of the steel produced, the manganese introduced at the same time being necessary to prevent red shortness, unless Swedish or Styrian iron is used. During the operation of melting, the metallic bath is tested from time to time by the introduction of an iron bar through one of the front doors, and if the bath is found to have become thick before the end of the operation, although the full heat has been maintained in the furnace, additional pig iron is introduced to restore it to the proper fluidity. In tapping, the loose sand near the tapping hole is first removed when the lower surface of the hard crust is reached. The lowest point of this surface is thereupon pierced by means of a pointed bar, upon the withdrawal of which the fluid metal runs out from the hottest and deepest portion of the bath into a heated ladle, placed in front of the furnace, from which it is distributed into the moulds. Each charge takes about ten hours, or with the time required to repair the bottom of the furnace, nearly twelve hours, so that each furnace yields two charges per twenty-four hours, or say an average of 9 tons of steel per day. The steel thus produced is worked up on the spot into rails, plates, and forgings, with the aid of powerful heating furnaces, hammers, and mills, the former being all regenerative gas furnaces, and the mills being worked by Mr. Ramsbottom's reversing rolling mill engines. There are also several regenerative gas puddling furnaces in full operation, the puddled iron made being charged while still hot into the steel melting furnaces, with, or in lieu of, scrap steel. These puddling furnaces may be increased in number, should scrap steel become scarce or costly. It was noticed that the works were being largely extended by the construction of a number of additional melting and heating furnaces, the new melting furnaces being intended for the manufacture of steel direct from iron ore by the Siemens process, which has been already practically tested by the company during some months' continuous work in one of the existing furnaces.

After leaving the Landore Works, the party proceeded to inspect the copper smelting works of Mr. Hussey Vivian and partners. They were afterwards entertained at luncheon by the Mayor of Swansea (Mr. J. J. Jenkins)—a member of the Institute. The members made a hurried inspection of the Swansea docks, and then returned to Merthyr by special train.

On Thursday evening, the Merthyr ironmasters entertained at dinner the members of the Institute, together with a large number of the leading gentlemen in the neighbourhood. Shortly after six o'clock, about 250 gentlemen assembled in the Drill Hall, which had been appropriately fitted-up for the occasion. Mr. R. Fothergill, M,P., occupied the chair, and Messrs. W. Menelaus, Wm. Jones, and A. J. Morris (the gentlemen under whose supervision the local arrangements had been made), were vice-chairmen.

On Friday, the members left Merthyr by special train to visit the works of the Ebbw Vale Company. On reaching the works they were met by Mr. Curtis, chairman of the company, Mr. Abraham Darby, managing Director, and other gentlemen, who conducted them over the extensive establishment. The Bessemer Steel Works were first visited. The company had, at the time, nearly completed the erection of a new mill for rolling Bessemer steel rails. The machinery throughout is of the most powerful and complete description. The mill is driven by reversing engines, hydraulic power is made to supplement hand labour as far as possible, the heating furnaces are all on Siemens' regenerative principle, and, altogether, the arrangements are exceedingly well carried out. Mr. Josiah Richards is the Engineer. The Bessemer converters are close to the new mill. The mills and forges were next inspected, and after these the blast furnace plant, in connection with which, the immense blowing engine—the largest beam engine in the country—excited much interest. After spending several hours in the works, the party adjourned to the Ebbw Vale Institute, where luncheon had been provided by the company. Mr. Curtis presided, and Mr. Abraham Darby was Vice-Chairman.

With this excursion, the visit of the Iron and Steel Institute to South Wales terminated. In every respect, the arrangements made by the local committee were of a most satisfactory character, and the meeting itself was altogether a great success. The reception given by the members of the South Wales trade to the Institute was certainly so cordial and hospitable, that the visitors will have occasion to remember the Merthyr meeting with feelings of unmixed gratification.

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