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Aviation History
1917
1917 - 1315.PDF
DECEMBER 13, 1917. •a INTERNATIONAL AIRCRAFT STANDARDS. : ..•:.-•**,"*' (Continued from pagt 1283.) - 3S7—Specifications for Alloy Steel Bars and Billets. (200,000 lbs. per sq. in, Tensile Strength.) GENERAL.—1. The general specifications, 1G1, shall form according to their applicability, a part of these specifications. USE.—-2. This steel is to be used for gears. MATERIAL.—3. The material for these bars shall be chosen from among the I. A. S. B. standard alloy steels listed below. The composition chosen shall be stated by the manufacturer or contractor, and is further limited as follows : Carbon, not over 0.50 per cent. ; phosphorus, not over 0.03 per cent. ; sulphur, not over 0.03 per cent. MANUFACTURE.—4. (a) The steel shall be manufactured 01 at least finished by the electric furnace or crucible process. (b) A sufficient discard shall be made from each ingot to secure freedom from piping and undue segregation. (c) The billets from which the bars are made are to be rough turned or chipped to remove all surface defects which might produce seams in the finished bars. No undercutting in chipping will be allowed. Heat Treatment.—(d) The steel manufacturer shall state, the heat treatment recommended to give the physical pro- perties specified. (e) If the bars are furnished in the heat-treated condition and the mechanical tests show that the heat treatment has not been correct, the bars may be re-treated at the option of the purchaser. WORKMANSHIP AND FINISH.—5. (a) The bars are to be sound, commercially straight, free from pipes, laps, twists, seams, and damaged ends, and are to have a workmanlike finish. They are to be uniform in quality, within the stipu- lated margins of manufacture, capable of being turned and threaded readily and of taking a good finish. (b) Any article may be rejected because of injurious defects or faults in manufacture at any time, notwithstanding that it has previously passed the physical and chemical tests ; 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. (a) The bars shall have the following physical properties : Tensile Test.—(b) Minimum tensile strength, 200,000 lbs. per sq. in. (140.60 kg./mm.2) ; minimum yield point, 160,000 lbs. per sq. in. (112.48 kg./mm.2) ; minimum elongation in 2 in. (50.8 mm.) or proportional gauge length, 10 per cent. ; minimum reduction of area, 35 per cent. Impact Test.—(c) When impact-testing machines of the pendulum type are available, tests shall be carried out if required to determine the specific impact of rupture in foot- pounds (or in kilogram-metres). Results markedly lower than the average of this type of material will be sufficient cause for further investigation (or reheat treatment) of the material. SELECTION OF TEST SPECIMENS.—7. Three bars of each size rolled from a heat shall be taken, and test pieces prepared in accordance with I.A.S.B. standards. Each test piece and the bar from which it is cut shall be stamped with an identifying number. Should any. of the test pieces, after being heat treated in the manner recommended, fail to show the prescribed physical properties, new test pieces similarly identified shall be made from the same three bars. At the option of the purchaser, the steel manufacturer may recom- mend a different heat treatment for the second set of test specimens, and to that end he may make such tests as he de- sires from the remainder of the three bars taken for the tests. Should any of the three specimens taken for the final test fail to show the required physical properties, the bars of that heat of the size represented by the specimens shall be rejected. DIMENSIONS AND TOLERANCES.—8. The dimensions and tolerances shall be those given by the specifications 3S11. DELIVERY, PACKING AND SHIPPING.—9. (a) The bars may be delivered in the annealed or in the heat-treated condition. (b) The steel manufacturer must stamp the heat number and the I.A.S.B. steel serial numbers on each bar of material furnished for this specification, where the bars are not less than ij sq. in. (968 sq. mm.) in cross section. (c) Where bars are less than i£ sq. in. (968 sq. mm.) in cross section and are not stamped with the heat and serial numbers, they shall be bundled into lots of not more than 150 lbs. (68 kg.) per bundle, and the heat number and the I.A.S.B. steel serial numbers must be stamped on a metal tag attached to each of the bundles. Chemical Composition of Standard Alloy Steels. NICKEL STEELS. Phos- Sul- phorus, phur. Number. Carbon. Manganese, maxi- maxi- Nickel. Chromium. mum. mum. 2335 •• •• 0.30-0.40 0.50-0.80 0.040 0.045 3.25-3.75 NICKEL-CHROMIUM STEELS. 3140 .. .. 0.35-0.45 0.50-0.80 0.040 0.045 1.00-1.50 0.45-0.75 3240 .. ., 0.35-0.45 0.30-0.60 0.040 0.045 1.50-2.00 0.90-1.25 X3340 0.35-0.45 • 0.45-0.75 0.040 0.045 2.75-3.25 0.70-0.95 3330.. .. 0.25-0.35 0.30-0.60 0.040 0.045 3.25-3.75 1.25-1.75 3340.. .. 0.35-0.45 0.30-0.60 0.040 0.045 3.25-3.75 1.25-1.75 X3440 0.35-0.45 0.30-0.60 0.040 0.045 4.00-5.00 1.00-1.50 CHROMIUM VANADIUM STEELS. Vanadium, Chromium, minimum. 6140.. .. 0.35-0.45 0.50-0.bo 0.040 0.045 0.80-1.10 0.15 3S8—Specifications for Alloy Steel Bars and Billets. (225,000 lbs. per sq. in. Tensile Strength.) GENERAL.—r. The general specifications, IGI, shall form, according to their applicability, a part of these specifications. USE.—2. This steel to be used for gears. MATERIAL.—3. The material for these bars shall be chosen from among the I.A.S.B. standard alloy steels listed below. The composition chosen shall be stated by the manufacturer or contractor, and is further limited as follows : Carbon, not over 0.50 per cent. ; phosphorus, not over 0.03 per cent. ; sulphur, not over 0.03 per cent. MANUFACTURE.—4. (a) The steel shall be manufactured or at least finished by the electric- furnace or crucible process. (b) A sufficient discard shall be made from each ingot to secure freedom from piping and undue segregation. (c) The billets from which the bars are made are to be rough turned or chipped to remove all surface defects which might produce seams in the finished bar. No undercutting in chipping will be allowed. Heat Treatment.—(d) The steel manufacturer shall state the heat treatment recommended to give the physical proper- ties specified. (e) If the bars are furnished in the heat-treated condition and the mechanical tests show that the heat treatment has not been correct, the bars may be retreated at the option of the purchaser. WORKMANSHIP AND FINISH.—5. (a) The bars are to be sound, commercially straight, free from pipes, laps, cracks, twists, seams, and damaged ends, and are to have a work- manlike finish. They are to be uniform in quality, within the stipulated margins of manufacture, capable of being turned and threaded readily and of taking a good finish. (b) Any article may be rejected because of injurious defects or fault in manufacture at any time ; notwithstanding that it has previously passed the physical and chemical tests, 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. (a) The bars shall have the following physical properties : Tensile Test.—(b) Minimum tensile strength, 225,000 lbs. per sq. in. (158.18 kg./mm.a) ; minimum yield point, 180,000 lbs. per sq. in. (126.54 kg./mm.8) ; minimum elongation in 2 in. (50.8 mm.) or proportional gauge length, 9 per cent. ; minimum reduction of area, 30 per cent. Impact Test.—(c) When impact-testing machines of the pendulum type are available, tests shall be carried out if required to determine the specific impact work of rupture in foot-pounds (or in kilogram-metres). Results markedly lower than the average for this type of material will be sufficient cause for further investigation (or reheat treatment) of the material. SELECTION OF TEST SPECIMENS.—7. Three bars of each size rolled from a heat shall be taken, and test pieces prepared in accordance with I.A.S.B. standards. Each test piece and the bar from which it is cut shall be stamped with an identifying number. Should any of the test pieces, after being heat treated in the manner recommended, fail to show the prescribed physical properties, new test pieces similarly identified shall be made from the same three bars. At the option of the purchaser, the steel manufacturer may recom- mend a different heat treatment for the second set of test specimens, and to that end he may make such tests as he
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