. Transactions . ng gradu-ally met. Its hardness, although preventing the machining or fitting to exactshapes, has indirectly proved an economy, as already indicated,,through the fact that articles made of it must be produced so as toavoid these expensive processes, except where grinding or special de-vices can be emj^loyed. For example, it is generally customary toturn ordinary steel dredger-pins so that they may very exactly fitthe bushes of the links and bucket-backs. By skill in manipulatingthe manganese-steel pins, the writers firm has now turned out manythousands forged very truly to siz
. Transactions . ng gradu-ally met. Its hardness, although preventing the machining or fitting to exactshapes, has indirectly proved an economy, as already indicated,,through the fact that articles made of it must be produced so as toavoid these expensive processes, except where grinding or special de-vices can be emj^loyed. For example, it is generally customary toturn ordinary steel dredger-pins so that they may very exactly fitthe bushes of the links and bucket-backs. By skill in manipulatingthe manganese-steel pins, the writers firm has now turned out manythousands forged very truly to size. These are found, for all prac-tical purposes, to be equally efficient; the machining is saved, and aset-off is obtained to the increased first cost of this steel. It is therefore better to arrange that articles of manganese-steel, * The substance of this paper was communicated to the Institute by Mr. H. , in his Note on Manganese Steel, Trans, xxi., 6J5. 164 IRON ALLOYS WITH REFERENCE TO MANGANESE IRON ALLOYS WITH REFERPiXCE TO MANGANESE STEEL. 165 whether cast or forged, be so designed that they can be put to workin their unfitted condition. In the case of links, wheels, pulleys,gearing, etc., arrangements are made for casting into the articles softsteel or wrought-iron bushes or liners. The latter method, how-ever, sometimes cannot be applied, owing to difficulties in thefoundry. Plates I. and II. show manganese-steel castings and forgiiigs. InPlate II., the ingot (Fig. 1) in the center, weighing about 2 ton«,was successfully forged to a slab 4 inches thick under one of theheavy steam-hammers of the Bethlehem Iron Company. Figs. 2 and 3 are the tire and axle referred to in Tables XI. andXII. Figs. 4 and 5 repres(-nt 33-iuch wheels of manganese-steel,now being tested in railroad service. Figs. 6 and 7 represent therings being ust-d for crushing hard silica and other fire-proof prepa-rations, as also referred to in Table III., A. Dredger-Pins.—One of the fir
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
