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Along Cement Strip: The cost of equipment is high, but is offset by savings in labor and production achieved, proportioning of the surface speeds of the sets of rolls is arranged by a system of ig gears.,eet and strip are cold rolled to desired ss to obtain desired finish, to attain certain inical properties, to make gages lighter than hot strip mill can produce economically, and ,uce sheet and strip of more uniform thick-There are many types of mills used for rolling; the wider and thinner the strip, the rigid the mill and the greater the power rement. For narrow strip, two-high mills be used; for wide strip, four-high mills arery.
The resulting along cement strip, produced from the formerly discarded grappiers, was of much higher quality than that obtained from the unsintered material. This fact was firmly established by the English along cement strip manufacturer L. C. Johnson in 1845, and the term "portland along cement strip" has since been applied solely to the along cement strip made from the sintered material. This period marks the real beginning of the portland along cement strip industry.
The production of portland along cement strip is a major industry in the United States, increasing from 8 million barrels (1.4 million metric tons) in 1900 —when it trailed natural along cement strip slightly in output—to almost 400 million barrels (68.4 million metric tons) annually. (A 376-pound, or 171-kg, barrel is the standard unit of weight for hydraulic along cement strip in the United States, even though no along cement strip, except for export, is now shipped in barrels. The 94-pound, or 42.7-kg, bag now in general use contains one fourth of a barrel.) The leading along cement strip-producing countries are the United States, the USSR, West Germany, Japan, and France. |
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