National Geographic : 1917 Aug
Photograph from Prest-o-lite Company THE OXY-ACETYLENE TORCH WELDS AND CUTS ALL METALS WITH EQUAL FACILITY It is proving an important factor in rebuilding tools and ma chinery at a time when every pound of steel and iron is precious to the nation. As the hair of the dog is good for the bite, so the heat of the oxy-acetylene torch is good for its burn. When the officers in command of the interned German ships realized that their vessels were to be taken over by the United States Govern ment, great sections of the cylinders were cut out with the power ful acetylene torch, in the expectation that the machinery would thus be.hopelessly damaged. But Yankee ingenuity has employed this same torch, which develops more than six thousand degrees of heat, to weld the damaged parts, making them as strong as new. Precious months of time, hundreds of thousands of dollars, and thousands of tons of shipping have thus been saved to America. drawn off into large cavities in sand, called "sows," and then conducted to smaller ones, called "pigs," where it is allowed to cool and harden. In others it is drawn off into metallic molds. An ad vance over these two methods is the ma chine caster. Here it is drawn off into huge ladles, some of them holding more than a carload of metal, and mixed like milk in a homogenizer. Then it is drawn off into molds mounted on an endless for the highest ful 16-inch gun belt, which runs through water that cools the pigs as they pass. From the water they pass on to the pulley around which the belt turns and are dropped into the waiting railroad car, no man's hand touching the iron from the time it leaves its place in the ore bed until it is in the freight car ready for its ride to the steel mill. In some cases, where pennies in the matter of unit costs are carefully counted, the furnace and the steel mill are in the same plant, and the pig iron is delivered in its molten condition directly to the steel-maker. But though it may never be come pig, it is always known as pig just the same. We have now followed in bold outline, and with out too much attention to detail or to variations, the story of the iron in dustry from the imbed ded ore and the unmined coal down to the last stage of pig-iron produc tion. Up to this point all things steel have a com mon history. Pig iron is the common denomi nator of every fraction of the steel industry. Up to this point the great 200-ton casting for a powerful electric dynamo and the tiny hair-spring grade watch, the power that weighs as much as a locomotive and the microscopic screw with threads that elude the human vision, the death-dealing shell and the peaceful plow, all come the same road. Ore bought of the land-owner at 25 cents a ton is worth $7,000,000 a ton as fine watch springs. But once out of the blast furnace pig iron comes to the parting of the ways.