The Works Of Messrs. Schneider And Co.

THE BESSEMER DEPARTMENT: QUALITIES OF STEEL. 33 type, with two connecting cylinders. The following- are soine of the dimensions: Diameter of air cylinders ... 1.5 ni. 4 ft. 11 in. ,, steam cylinders Stroke 1.2 m. 3 ft. 11 in. 1.8 m. 5 ft. 11 in. Air pressure, mercury Volume of biast supplied per ton 150 cm. 4 ft. 11 in. of pig under operation and per minute 45 c. m. 1,589 cub. ft. The inlet and outlet valves of the air cylinders are of the Corliss type (see Figs. 79 to 81). An air receiver of 225 cubic metres (7,943 cubic feet) capacity, is situated between the engines and the Converters. The steam for the ehgines is produced in the bollers fired by the waste gases from the blast-furnaces and the coke ovens. These bollers have been already described (see pages 27 and 29). The varieras improvements made since the plant was first put down have enabled Messrs. Schneider and Co. to obtain an output which is large as compared to the size of the installation. As a rule, the ingots weigh about 1,350 kilo- grammes (26 cwt. to 27 cwt.), but smaller ones are also cast, weighing from 300 to 500 kilogrammes (6 ewt. to 10 cwt.) ; these latter are chiefly used for rolling into plates, and for light rails. There are usually 17 heats per twelve hours, and the yearly output is 62,000 tons. The molten pig iron is taken direct from the blast-furnaces, which are only 82 yards distant. A small locomotive hauls the truck carrying the ladle on to an elevator, which lifits it on a platform at the height of the converter mouth. The steel ingots are taken out of the moulds, and carried hot, in special trucks, to the rolling milis. The carburising agent varies according to the degrees of hardness required. For mild steel of less than 48 kilo- grammes per square millimétré (30.48 tons per square inch) breaking strain, 75 per cenK, ferro-manganese in a red-hot state is used. For steel of 48 kilogrammes to 60 kilogrammes per square millimétré (30.48 to 38.09 tons per square inch) breaking strain, a small proportion of anthracite is added to the ferro-manganese. A mixture of manganeseous pig iron and hématite pig, melted in a cupola, is used for obtaining steel which is to give a higher breaking strain tlian 60 kilogrammes per square millimétré (38.09 tons per square inch.) The heated ferro-manganese is thrown into the converter previous to the pouring of the metal in the casting ladle. The carburising by anthracite, and by the mixture melted down in a cupola, is effected by putting the carburising agent first into the ladle ; the metal from the converter is then poured into the ladle, care being taken that no slag runs in with it. Qualities of Bessemer Steel.—Messrs. Schneider and Co. have classified their Bessemer steel, according to its breaking strain, under eleven numbers, each one repre- senting a different quality ; tliere is a difference of 5 kilo- grammes per square millimétré (3.17 tons per square inch) breaking strain between every two consecutive numbers. The hårdest, styled No. 1, bas a breaking strain o£ 90 kilo- I grammes per square millimétré (57.14 tons per square j inch), and the softest, styled No. 11, 35 kilogrammes per square millimétré (22.22 tons per square inch) only. A small sample ingot is taken from each heat, and from this there are made, first, a test-piece forged to a diameter ' of 16 millimètres (f in.) and annealed in the open, previous i to undergoing tensile test ; secondly, a test-piece for analysis ; and, thirdly, a test-piece forged to a diameter of f in. for testing the quality when hot. For this last test, ' the piece is brought to a white heat, and bent at right angles with a hand-hammer ; it is then straightened out again and bent over at right angles the other way. This O O O i/ is carried on until the piece breaks. The quality of the steel is clefined by the number of times the test-bar with- stands bending. Bessemer steel is also classified in three qualities, namely : Mild (ordinary and extra-mild), semi-hard, and hard. The ordinary mild quality serves for current products, such as rolled bars, sections, plates for tanks, receivers, &c. The extra-mild quality is more especially used for the manufacture of nails, wheel tyres, thin sheets for dynamos, buckled plates, sheets for galvanising, tinplate bars, &c. The semi-hard steel is used for base-plates, fish-plates, light rails, sleepers, shafts, shovels, spades, &c. The hard quality serves exclusively for the manufacture of heavy rails. Notwithstanding the classification from results of tests as above described, Messrs. Schneider and Co. take into account, when fixing the quality of their steel, and con- sequently in deciding the use to which it has to be put, the dass of pig iron employed, the manner in. which the metal behaved in the converter, and also tlie way in which the steel flows in the ingot moulcl. Minute inspection at ail stages of the process explains the high reputation acquired by the sheets, dynamo steel, welding steel for wheel tyres, &c., manufacturée! at Creusot with the Basic plant. Ail the hydraulic machinery is worked under a pressure of 30 kilogrammes per square centimetre (426.691b. per square inch). Water is supplied by two vertical pumps of 50 horse-power each, which serve not only the Bessemer plant, but also the other installations, namely, the Siemens- Martin plant, the steel foundry, and the rotary puddling furnaces. Ail the accessory plaut, cupola fans ; crushing mills for preparing dolomite, lifts for ladies, slag receivers i &c., are operated by electric motors. Slag.—The slag, after being poured in special receivers, is removed, and after cooling is erushed and screened in a special shop near the Bessemer plant, and is sold to agriculturalists as manure. This by-product is highly appreciated in the district, as it contains a high percentage of phosphoric acid. Messrs. Schneider and Co. seli 15,000 I tons of this every year.