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Aviation History
1918
1918 - 0264.PDF
MARCH 7, 1918. INTERNATIONAL AIRCRAFT (Continued fr*m page 230.) STANDARDS. 3S20—Specifications for Cold-Rolled or Drawn Carbon Steel Bars. GENERAL—1. The general specifications, 1G1, shall form, according to their applicability, a part of these specifications. USE—2. These bars are suitable only for low-stressed parts. MATERIAL:—3. The material for these bars shall be chosen from the I.A.S.B. standard carbon steels listed below. The composition shall be stated by the manufacturer or contractor, and is further limited as follows : Carbon, not over 0.25 per cent. MANUFACTURE.—4. The steel shall be manufactured, or at least finished, by the open-hearth, electric-furnace, or crucible process. WORKMANSHIP AND FINISH.—5. (a) The bars are to be bright and clean, sound, straight, free from pipes, laps, cracks, twists, seams, and damaged ends, and are to have a workmanlike finish. They are to be uniform in quality, within the stipulated margins of manufacture capable of being turned and threaded reaaily, and of talring a good finish. (6) Any bar may be rejected because of injurious defects or faults in manufacture at any time, notwithstanding that it has previously passed inspection ; it shall be returned to the manufacturer at the latter's expense. This clause shall not be taken to apply to materials fabricated after export. PHYSICAL PROPERTIES AND TESTS.—6. The bars shall have the following physical properties : Tensile Test.—(a) -•- grouped and bundled.'each bar shall be plainly marked with tne neat and the I.A.S.B. steel serial number. COMPOSITIONS OF STANDARD STEELS. Minimum tensile strengthMinimum yield point .. Minimum elongation in 2 ins. or proportiongauge length Minimum reduction of area Bars not over0.75 in. (19.08 mm.) diameteror width across the flats. 70,000 lbs./in."50,000 lbs./in.3 20 per cent. 40 per cent. Minimum tensile strength 49.2 kg./mm.2Minimum yield point .. 35.ikg./mm." Minimum elongation in 2 ins. or proportiongauge length .. .. 20 per cent. Minimum reduction of area 40 per cent. Bars over0.75in. (19.08 mm.) and not over1.50 in. (38.10 mm.) diameteror width across the flats.70,000 lbs./in.2 50,000 lbs./in.- 17 percent. 38 per cent. 49.2 kg/.mm.2 35.1 kg/.mm.2 17 percent. 38 per cent. Bars over 1.50in. (38.10 mm.) diameter or width across the flats. 65,000 lbs./in.250,000 lbs./in.2 15 per cent. 35 per cent. 45.6 kg./mm.2 35.1 kg./mm.2 15 per cent. 35 per cent. Bend Test.—(6) Bend-test pieces from bars of 0.75 in. (19.05 mm.) or less diameter (or width across the flats) shall be tested in full size as rolled or drawn. Above 0.75 in. (19.05 mm.) diameter (or width across the fiats) the test pieces may be turned down from the bar to a diameter of 0.756 in. (19.08 mm.) The test pieces shall withstand bend- ing cold through an angle of 180 deg. over a radius equal to their diameter (or width across flats) without fracture. SELECTION OF TEST SPECIMENS.—7. (a) The bars shall be grouped by heats or melts into lots conforming to the size limits given in paragraph 6. The inspector shall select at random I per cent., but not less than three bars of each lot to be representatives of the sizes in the lot. One tensile and one bend test specimen shall be cut from each bar. (6) For sizes over 1.50 in. (3.86 cm.) in diameter or width across the flats, one tensile and one bend specimen shall be taken from a bar of each size represented in the lot. (c) The bars and specimens shall be stamped for identifica- tion. Whenever bars cannot be grouped by heats or melts, one tensile and one bend test specimen shall be taken from each lot of 100 bars or less. The provisions as to grouping by size limits and provisions for bars of over 1.50 in. 3.86 diameter, as given above, shall apply. [d) The specimens shall not be annealed or otherwise treated before they are tested. They are to be tested in full section, unless the bars are to be subsequently reduced in section by machining. In this event, the tensile specimens may be machined to standard sizes in accordance with specification 1G1. DIMENSIONS AND TOLERANCES.—8. The dimensions and tolerances shall be those given in the specification 3S11. DELIVERY, PACKING, AND SHIPPING.—9. (a) All bars shall be suitably greased for protection against corrosion. (6) The bars shall in general be grouped in bundles weigh- ing not more than 220 lbs. (100 kg.), unless otherwise agreed between manufacturer and purchaser; the heat number and the I.A.S.B. steel serial number shall be plainly marked on a metal tag attached to each bundle. If bars are not so Number, f" \ Carbon.IOIO, |.. 0.05-0.15 1015 ,.. .10- .201020 ,.. .15- .25 Manganese. 0.30-0.60.30-..60 .30- .60 Phosphorus, maximum.0.045 • 045 •045 Sulphur, maximum.0.50 O.JO0.50 When electric or crucible furnace steel is specified in the order, the maximum allowable percentage of phosphorus and sulphur may, at the option of the purchaser, be limited to 0.03 per cent. -j—Specifications for Seamless Brass Tubes. GENERAL.—1. The general specifications, IGI, shall form, according to their applicability, a part of these specifica- tions. USE.—2. This tubing is resistant to the corrosive action of salt water, salt air and gases. MATERIAL.—3. (a) The brass shall have the following composition : Copper Lead, maximum Iron, maximum Zinc Per cent.. 79.00 to 82.00 .20.10 Remainder *~ (b) Samples for analysis may consist of turnings taken from the end of the tube or of drillings. Points from which drillings are taken must be distributed around the surface of the tube so as to yield a representative sample of of the tube wall. MANUFACTURE—4. (a) The brass shall be made from lake or electrolytic copper conforming to the I.A.S.B. specification 2N2 and from B or C grade spelter conforming to I.A.S.B. specification 2N3. ' (b) No scrap shall be used other than that produced in the manufacturer's own plants and of the same composition as the material specified. (c) Tubing shall be semi-annealed unless otherwise specified. (d) Any sheet may be rejected because of injurious defects or faults in manufacture at any time, notwithstanding that it has previously passed inspection; it shall be returned to the manufacturer at the latter's expense. This clause shall not be taken to apply to materials fabricated after export. WORKMANSHIP AND FINISH.—5. The tubing shall be clean, smooth and free from all injurious defects, both inside and outside. PHYSICAL PROPERTIES AND TESTS.—6. (a) Flattening Test.—A piece of tube, 2 diameters in length, shall be flattened with a hammer until it passes freely through a micrometer caliper set at three times the thickness of the tube wall. The tube must stand this test without showing cracks or other defects. (b) Expanding Test.—A pin with a taper of one in eight shall be driven into one end of the tube until the tube's diameter is increased by one-sixth. The tube must stand this test without showing cracks, splits, or other defects. (c) Hydrostatic Pressure Test.—Each tube shall be subjected to a hydrostatic pressure which will develop a tensile stress of 7,000 lbs. per sq. in. (4.92 kg./mm.*) in the tube, but in no case shall a test pressure of more than 1,000 lbs. per sq. in. (0.703 kg./mm.*) be required. Each tube must with- stand this test without cracks, flaws, leaks, or other defects such as bulging.* SELECTION OF TEST SPECIMENS.—7. (a) Each tube shall be subjected to a hydrostatic test. One tube from each lot of 100 or less shall be subjected to a flattening and to an expanding test. (6) If any tube fails to pass the flattening or the expanding test, two more tubes representing the same lot shall be sub- jected to both tests. If either of these tubes fail irr. either test the lot which they represent shall be rejected. (c) Any tube failing to meet the hydrostatic test shall be rejected. DIMENSIONS AND TOLERANCES.—8. (a) Tolerances.—The / * The pressure to be applied shall be calculated from the formula _ 7»oooT Where P = the hydrostatic pressure in pounds per sq. in.T = the thickness of the tube wall in inches. R = the internal radius of the tube. 260
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