The Works Of Messrs. Schneider And Co.

90 MESSES. SCHNEIDER AND CO’. S WORKS. a few minutes’ reheating, the biooms are carried on a truck, and placée! on the lifting platform feed-rollers. The slab miil has three-high roils ; it is shown in the general plan of the sheet and plate miils, Fig. 223, Plate XLIIL, and in detail, by Figs. 224 and 225, Plate XLTII. I he engine drives the middle roll pinion ; the roli revolves in bearings which rest on shoulders carried by the housing frames ; its height is fixed and the position of the top and bottom roils is determined by adj ast- able wedges in order to obtain the required thick- ness for the bar. Only two types of slab bars are rolied in the same set of rolJs ; the largest size is .235 metre (9| in.) wide and the smaller .175 metre (6f in.) wide, the minimum thickness of the former being 13 milli- metres (J in.) and of the latter 8 millimétrés (T6T in.). The roils now in use have eight grooves, alternated for the two sizes of slab bars. The speed of the miil is 54 revolutions per minute; the mean diameter of the rolls is .700 metre (27t9k in.); and their length 2.400 metres (7 ft. 10 in.) The bioom is rapidly transformée! into a flat bar, and is afterwards carried to a quick-working shearing machine, which cuts it in two, four, six or eight slabs in a few seconds; the temperature is still maintained to 1,000 deg. or 1,050 deg. (1,877 deg. Fahr.) when they are taken to the sheet miils. The train in which the slabs are rolied out into sheets consists of five pairs of housings, each with two rolls; four of these are for direct rolling, the fifth being used for the sheets that require reheating. The shearing machine is placed opposite the middle miil so as to reduce to a minimum the travel of the slabs; these are taken by boys from the shearing machine to the milis, generally in pairs, following the lines shown in dotted lines in Fig. 223, Plate XLIIL Figs. 224 and 225, Plate XLIIL, show the general arrangement of this train ; the roll-setting gear is operated mechanically by means of a transmission, worked by the train itself, which acts by belting and friction eones upon the screws of the roll-adj usting wedges and upon a pressure indicator ; this is in sight of the workmen and of the boy in charge of the adjustable gear. The top roli is worked by connecting shafts, and balancée! by hydraulic rams. In the fifth mili the top roli is free, and the screws which act upon the adjusting wedges are independent, and worked by a handwheel. The rolls were formerly .620 metre (24-| in.) in diameter ; they are now .650 metre (25f in.) diameter, and 1.200 metres (3 ft. 11| in.) long; the bearings are .480 metre (18f in.) in diameter, and the ends .400 metre (15f in.). The rolls, which are of hard cast iron, are cooled by a stream of water after each operation. The bearings are lubricated with tallow. The rolls used for finishine- thin o sheets are not watered, and their bearings are lubricated with hot-neck grease. The thicknesses rolied in this train vary from .6 millimétré (.024 in.) in sheets weighing 9 kilo- grammes (20 Ib.), to 4 and 5 millimétrés (.16 in. and .20 in.) in sheets weighing 63 and 78 kilogrammes (139 Ib. and 172 Ib.). The thinnest sheets are obtained by rolling them in series of two, three, and four sheets, one over the other, after reheating horizontally. The apparatus for doubling the sheets is illustrated by Figs. 226, 227, and 228, Plate XLIV. ; it is placed level with the floor, and consists of two jointed flaps, worked by hydraulic pressure, which come together vertically. The sheets, placed on these flaps, opened out horizontally, are held down by a flat bar placed over the joint, and which is pulled out just before the doubling operation is completed. The dimensions of the hydraulic ram are suitable, with the available pressure of 35 kilogrammes per square centi- metre (497.81 Ib. per square inch), to double the thickest sheets rolied in this way, even when they are almost cold. When the sheets are doublée!, the bündle is brought under a small hydraulic shearing machine to cut off the edges. The bundle is then heated in horizontal furnaces, for the final rolling. The train manufactures all kinds of inerchant sheets. Its output being high, it is often difficult to keep it con- stantly at work. Thus, 20 to 24 tons of sheets 1 by 2 metres (3 ft. 3f in. by 6 ft. in.) weighing 11 to 25 kilo- grammes (24 Ib. to 55 Ib.); or 40 tons of the same-sized sheets, but weighing 27 to 49 kilogrammes (59 Ib. to 108 Ib.) each, can be produced in 12 hours. Sheets measuring .800 by 1.650 metres (31^- in. by 5 ft. 5 in.), weighing each as above, can be turned out in equal quantities. A large nuniber of these sheets are annealed in horizontal furnaces near the train, immediately after rolling and before shearing. The speeial-quality sheets—those for which a perfeetly smootli surface is required—are manufaetured by the second pro- cess, with slabs rolied in advance. The slab bars are rolied in a three-high roli inill and sheared cold ; they aro then scaled as completely as possible, and are reheated in horizontal furnaces. These furnaces, which are illustrated by Figs- 229 to 231, Plate XLIV., are fitted with one grate of the usual type provided with steam biast. The hearth is covered with brick supports, on which the slabs are placed flat, both sides getting heated simultaneously ; the fiâmes are made to return underneath the hearth. There are several furnaces of this type of varions sizes ; they serve both to heat the slabs and the bundles of doubled-up sheets. The width of the slabs used is .200 metre (7f in.), the thickness varying from 7 to 15 millimétrés in. bare to T%- in. füll). The slabs are heated to 850 deg. or 900 deg. (1287 deg. Fahr.) maximum ; therefore, they leave the furnace without any trace of oxide on their surface. At such low temperatures, however, the rolling requîtes a high power, and the plant niust have a large margin of strength, as the least mistake in the setting of the rolls would result in fractures of the rolls or of the housings. Figs. 232 to 236, Plate XLV., are illustrations of the latest types adopted by Messrs. Schneider and Co. for these housings ; the first rolls used were .620 metre (24f in.) in diameter, but as they broke occasionally, their diameter was inereased to .650 metre (25f in.). The necks are also made exceptionally strong ; they are .480 metre (18^- in.) in diameter, and are United to the body of the roll by large