The American Repertory of Arts, Sciences, and Manufactures Volume 4

The American Repertory of Arts, Sciences, and Manufactures Volume 4

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1842 edition. Excerpt: metal from them, charcoal should be used instead of coke, there being much less earthy matter in it; the earth of the coke is very apt to get into the iron, which renders it impure. at as it as 4-as as The pig-iron is first melted in the back fire, which generally occupies about three-quarters of an hour; the man keeps working it about with a bar till it is all melted; and if, when he stirs about the bar and withdraws it, the metal on the point sparkles and scintilates, it is ready; the metal should never be let out till this is the case; if the next fire is not ready, the blast should be slackened, so as not to burn the iron, but still to keep it up to the proper pitch. The metal generally requires a little slag more than it produces by itself, and some thinner, as its own is thick and turgid. The cinder from the lower fire is the best, as it is, when liquid, much thinner, and allows the metal to sink after being well worked. In working iron rather inferior in this fire--say, poor bright and low mottled--it may be a great deal improved by throwing in a. shovel of broken limestone to each charge. This engages with the earthy impurities, and clears the iron a great deal, though it by no means makes it equal to that produced from better cast-iron. During the operation some of the slag is tapped out by the hole under the fire plate, when it has accumulated to too great a quantity, which is apt to impede the blast. When the lower fire is ready for receiving the metal, it is tapped from the back, and runs into the bed of the lower one, where it is received on a bed of charcoal dust, and, as it runs, the workman, with a bar, stirs it up; the fire is kept full of charcoal, or of coke, when making coke iron, in which case they generally more

Product details

  • Paperback | 218 pages
  • 189 x 246 x 12mm | 399g
  • United States
  • English
  • black & white illustrations
  • 1236895452
  • 9781236895455