Welded Joints.-The strength of a welded joint is very uncertain, because it depends upon the quality of the fuel used in heating it, the shape and area of the joint, the heat at which the iron is worked, the weight of the hammer used, and the quality of the workmanship. The strength of a butt-welded joint is frequently only 75 per cent., a lap-welded joint 80 per cent., and a V-welded joint 85 per cent. of that of the solid or unwelded bar. Naval-Brass.-Naval-brass offers considerable resistance to corrosion. It consists of copper 62 per cent., zinc 37 per cent., and tin I per cent. Its specific gravity is 8.41; and the weight of a cubic foot is 525 lbs. The tensile strength of naval-brass when annealed is 21 tons per square inch. Table 145.-WEIGHT OF ONE SQUARE FOOT OF PLATES OF NAVAL-BRASS OF VARIOUS THICKNESS. Table 146.-WEIGHT OF ONE FOOT IN LENGTH OF ROUND Bars of Muntz-Metal consists of copper 60 per cent., and zinc 40 per cent. When annealed, its tenacity is from 22 tons to 28 tons per square inch. Table 147.-WEIGHT OF ONE SQUARE FOOT OF MUNTZ METAL PLATES ROLLED BY MUNTZ'S METAL CO., LIMITED. Weight of various Bronzes. In the following table is given the approximate weight of one square foot of various bronzes, the compositions of which are as follows: The manganese bronze in column A. of the table is composed of 53 per cent. of copper, 42 per cent. of zinc, 3 per cent. of manganese, and 1 per cent. of aluminium. The manganese bronze in column B. is composed of 60 per cent. of copper, 37 per cent. of zinc, I per cent. of tin, 2 per cent. of iron, and 05 per cent. of manganese. The nickel-bronze in column C. is composed of 70 per cent. of copper, 20 per cent. of nickel, and 10 per cent. of zinc. The ordinary bronze in column D. is composed of 90 per cent. of copper and 10 per cent. of tin. The silicon-bronze in column E. is composed of 97 per cent. of copper and 3 per cent. of silicon. Table 148.-APPROXIMATE WEIGHT OF ONE SQUARE FOOT OF CAST PLATES OF MANGANESE BRONZE, NICKEL-BRONZE, ORDINARY BRONZE, AND SILICON-BRONZE. Weight of various Antifriction Metals.-The white metal in column A. of the following table represents the average of several different compositions called Babbitt's metal. The white metal in column B. is composed of 86 per cent. of tin, 9 per cent. of antimony, and 5 per cent. of copper. The white metal in column C. is composed of 83 per cent. of tin, 9 per cent. of antimony, and 8 per cent. of copper. The white metal in column D. is composed of 82 per cent. of tin, 14 per cent. of lead, and 4 per cent of copper. The white metal in column E. is composed of 70 per cent. of tin, 9 per cent. of antimony, 17 per cent. of lead, and 4 per cent. of copper. The white metal in column F. is composed of 76 per cent. of lead, 10 per cent. of antimony, and 14 per cent. of tin. The white metal in column G. is composed of 80 per cent. of lead, 15 per cent. of antimony, 42 per cent. of tin, and per cent. of bismuth. Table 149.-APPROXIMATE WEIGHT OF ONE SQUARE FOOT OF Cast Plates OF ANTIFRICTION WHITE METAL OF VARIOUS COMPOSITION. Table 150.-WEIGHT OF ONE FOOT IN LENGTH OF SMALL BRASS TUBES. Weight of Plates of several kinds of Steel. The steel in column A. of Table 151 contains 12 per cent. of manganese. The nickel-steel in column B. contains 3 per cent. of nickel. The nickel-steel in column D. contains 20 per cent. of nickel. The compressed steel in column E. is ordinary mild carbon-steel, of average quality, compressed while fluid. Table 151.-APPROXIMATE WEIGHT OF ONE SQUARE FOOT OF Plates of MANGANESE STEEL, NICKEL-STEEL AND COMPRESSED MILD STEEL. Table 152.-WEIGHT OF ONE FOOT IN LENGTH OF SMALL COPPER TUBES. |