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ferro-silicon pig very economically, or where a founder is running on a specialty of any kind that does not require different mixtures out of the same heat, with good judgment and care, ferro-silicon may often be well and profitably applied in mixture.* Four per cent, of silicon pig can often carry 80 per cent, of ordinary scrap to make soft, machinable castings in work not under one inch in thickness.
Silicon in the pig has a silver cast, and, with some grades, . a flaky, frost-on-the-window look. It has practically no grain and when broken has a fracture somewhat like glass. For its appearance in a liquid state, see Chapter LX,
Sulphur in iron is mainly derived from the fuel used to smelt it in the blast furnace and in remelting it in a cupola. It is the most uncontrollable, injurious element the furnaceman or founder has to contend with. There are, however, three qualities sometimes commendable in it: one is its influence in increasing the fusibility of iron, and another its strength, as shown in Chapter XXX., and the third its tendency to harden or chill iron by reason of its promoting combined carbon, which is often better obtained with low silicon or high manganese, since with these we have less injury from unyielding contraction strains. With the exception of the three qualities mentioned above, the effects of sulphur are greatly for evil, making light castings hard and molten iron sluggish, and giving rise to u blow holes " in iron solidifying rapidly. It is for these various reasons that charcoal iron, on account of its being low in sulphur, has been found superior to coke or anthracite iron for many kinds of castings.
* Some keep a stock of ferro-silicon on hand to regulate mixtures in the absence of their 3.00 to 4.00 per cent, silicon irons, as a little goes a long ways and often prevents shutting down for the want of regular irons.
he now can about moulding sand, ramming, venting, Steel Co., Vale University. & Sons, Hecla Works, England; R. C. Hindiey, M. Hoskins, Harvard College, Havemeyer University, Henry Hiels Chemical Co., Isabella Furnace, Iron Gate Furnace, Iroquois Iron Co., Illinois Steel Co., Jefferson Iron Co., Kittan-ning Iron & Steel Co., C. A. Kelly Plow Co., Lebanon Furnace, Longdale Iron Co., Lackawanna Iron & Steel Co., Logan Iron........................   16,720     "                                     t-