Book Description

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. 1922 edition. Excerpt: ...the latter being an impurity arising from the use of scrap hard lead as a part of the charge in the making of the bearings. Any lead to be added to the charge is not put into the furnace but is added in the ladle. ' The metal losses on the whole year's operation of the Snyder and Rennerfelt furnaces together, calculated on an inventory basis, were somewhat lower than those found in the tests, and though the Bennerfelts are conceded to give somewhat lower metal losses than the Snyders, thus reducing the figures of metal loss when the results of both types of furnace are lumped, it is doubted whether this diiference is enough to give the inventory figure if the average loss with the Snyders was as great as indicated by the tests. It therefore seems probable that the net loss for the Snyders is between 3 and 4 per cent rather than above 4 per cent. The fact that lead may be volatilized from copper by a direct arc is utilized by Hill and Luckey"1 for rapid determination of the lead content of copper. They play a 220-volt arc 0.5 cm. long, at 10 amperes, on 0.4 gram of copper, observe the arc spectrum through a spectroscope, and record the time required for the lead lines to disappear. This time is proportional to the lead content of the copper. In two minutes 0.016 per cent lead disappears, and in eight minutes 0.216 per cent. It is not surprising then that a direct arc playing on an alloy with, say, 15 per cent lead should cause a distinct loss of lead. According to figures from the Chicago Bearing Metals Co., in 49 working days (two shifts of nine and one-half hours each) in December, 1917, and January, 1918, the two Snyder furnaces together melted 2,600,000 pounds, or about 13% heats of one ton each per furnace per 19-hour...