Rephosphorized steels not subject to check analysis for phosphorus. [29 F.R. 18826, Dec. 29, 1964, as amended by Order 71, 31 F.R. 9077, July 1, 1966) § 178.58-6 Identification of material. (a) Required; any suitable method except that plates and billets for hot-drawn containers shall be marked with heat number. $ 178.58-7 Defects. (a) Material with seams, cracks, laminations, or other injurious defects, not authorized. Defects in welded joints shall not exceed the limits specified in 178.58-17 covering radiographic inspection. (a) By best appliances and methods; dirt and scale to be removed as necessary to afford proper inspection; no defect acceptable that is likely to weaken the finished container appreciably, reasonably smooth and uniform surface finish required. No abrupt change in wall thickness permitted. Certification of welders; and/or process required in accordance with the sections of CGA Pamphlet C-3 that apply. (b) All seams of the sphere or cylinders must be fusion welded. Seams shall be of the butt or joggle butt type and means must be provided for accomplishing complete penetration of the joint. [29 FR. 18826, Dec. 29, 1964, as amended by (a) Attachments to the container are authorized by fusion welding provided that such attachments are made of weld able steel, the carbon content of which § 178.58-10 Wall thickness. (a) The minimum wall thickness shall be such that the wall stress at the minimum specified test pressure shall not exceed 67 percent of the minimum tensile strength of the steel as determined from the physical and burst tests required and shall not be over 70,000 p.s.i. Minimum wall 0.040 inch for any diameter container. (b) Calculation for a sphere must be made by the formula: S= wall stress in pounds per square inch; D= outside diameter in inches; E=1.0 (for all other areas). (c) Calculation for a cylinder must be made by the formula: where: P(1.3D+0.4d3) S=wall stress in pounds per square inch; P=test pressure prescribed for water jacket test, 1. e., at least 2 times service pressure, in pounds per square inch; D= outside diameter in inches; d= inside diameter in inches. [29 FR. 18826, Dec. 29, 1964, as amended by Order 66, 30 F.R. 5751, Apr. 23, 1965] $ 178.58-11 Heat treatment. (a) The completed containers must be uniformly and properly heat-treated prior to tests. Heat-treatment of containers of the authorized analysis shall be as follows: (1) All containers must be quenched by oil, or other suitable medium except as provided in subparagraph (4) of this paragraph. (2) The steel temperature on quenching shall be that recommended for the steel analysis, but in no case shall exceed 1,750° F. (3) The steel shall be tempered at the temperature most suitable for the analysis except that in no case shall the tempering temperature be less than 1,000° F. (4) The steel may be normalized at a temperature of 1,650° F. instead of being quenched, and containers so normalized need not be tempered. (5) [Reserved] (6) All cylinders, if water quenched or quenched with a liquid producing a cooling rate in excess of 80 percent of the cooling rate of water, must be inspected by the magnetic particle or dye penetrant method to detect the presence of quenching cracks. Any cylinder found to have a quench crack must be rejected and may not be requalified. [29 F.R. 18826, Dec. 29, 1964, as amended by Amdt. 178-17, 36 F.R. 9521, May 26, 1971; Amdt. 178-25, 37 F.R. 14589, July 21, 1972] § 178.58-12 Openings in container. (a) Each opening in the container must be provided with a fitting, boss, or pad of weldable steel securely attached to the container by fusion welding. (b) Attachments to a fitting, boss, or pad must be adequate to prevent leakage. Threads must comply with the following: (1) Threads must be clean cut, even, without checks, and tapped to gauge. (2) Taper threads to be of length not less than as specified for American Standard taper pipe threads. (a) By water-jacket, or other suitable method, operated so as to obtain accurate data. Pressure gauge must permit reading to accuracy of 1 percent. Expansion gauge must permit reading of total expansion to accuracy either of 1 percent or 0.1 cubic centimeter. (b) Pressure must be maintained for 30 seconds and sufficiently longer to insure complete expansion. Any internal pressure applied after heat-treatment and previous to the official test must not exceed 90 percent of the test pressure. If, due to failure of the test apparatus, the test pressure cannot be maintained, the test may be repeated at a pressure increased by 10 percent or 100 pounds per square inch, whichever is the lower. (c) Permanent volumetric expansion must not exceed 10 percent of total volumetric expansion at test pressure. (d) Each container must be tested to at least 2 times service pressure. § 178.58-15 Burst test. (a) One container taken at random out of 200 or less shall be hydrostatically tested to destruction. Rupture pressure shall be included as part of the inspector's report. (b) Flattening test for cylinders. Between knife edges, wedge shaped, 60° angle, rounded to 1⁄2 inch radius; test one cylinder taken at random out of each lot of 200 or less, after hydrostatic test. § 178.58-17 Radiographic inspection. (a) Required on all welded joints which are subjected to internal pressure, except that at the discretion of the disinterested inspector, openings less than 25 percent of the sphere diameter need not be subjected to radiographic inspection. Evidence of any defects likely to seriously weaken the container shall be cause for rejection. § 178.58-18 Physical test and specimens for spheres and cylinders. (a) Physical test for spheres. Required on 2 specimens cut from flat representative sample plate of the same heat taken at random from the steel used to produce the sphere. This flat steel from which the 2 specimens are to be cut must receive the same heat-treatment as the spheres themselves. Sample plates to be taken for each lot of 200 or less spheres. (b) Specimens for spheres. Specimens must be gauge length 2 inches with width not over 121⁄2 inches: Provided, That gauge length at least 24 times thickness with width not over 6 times thickness is authorized when wall of sphere is not over 6 inch thick. (c) Physical test for cylinders. Required on 2 specimens cut from 1 cylinder taken at random out of each lot of 200 or less. (d) Specimens for cylinders. Specimens must be gauge length 8 inches with width not over 11⁄2 inches; or gauge length 2 inches with width not over 11⁄2 inches: Provided, That gauge length at least 24 times thickness with width not over 6 times thickness is authorized when cylinder wall is not over 6 inch thick. The specimen, exclusive of grip ends, must not be flattened. Grip ends may be flattened to within 1 inch of each end of the reduced section. Heating of specimen for any purpose is not authorized. (e) The yield strength in tension shall be the stress corresponding to a per manent strain of 0.2 percent of the gauge length. (1) The yield strength shall be determined by either the "offset" method or the "extension under load" method as prescribed in ASTM Standard E8-57T. (2) In using the "extension under load" method, the total strain (or "extension under load") corresponding to the stress at which the 0.2 percent permanent strain occurs may be determined with sufficient accuracy by calculating the elastic extension of the gauge length under appropriate load and adding thereto 0.2 percent of the gauge length. Elastic extension calculations shall be based on an elastic modulus of 30,000,000. In the event of controversy, the entire stress-strain diagram shall be plotted and the yield strength determined from the 0.2 percent offset. (3) For the purpose of strain measurement, the initial strain shall be set while the specimen is under a stress of 12,000 pounds per square inch, the strain indicator reading being set at the calculated corresponding strain. (4) Cross-head speed of the testing machine shall not exceed 1⁄2 inch per minute during yield strength determination. § 178.58-19 Acceptable results for physical, flattening, and burst tests. (a) Elongation at least 20 percent for 2-inch gauge length or 10 percent in other cases. (b) Flattening required to 50 percent of the original outside diameter without cracking. (c) Burst pressure shall be at least 3 times service pressure. § 178.58-20 Rejected containers. (a) Reheat-treatment authorized; subsequent thereto, acceptable containers must pass all prescribed tests. Repair of welded seams by welding prior to reheat-treatment authorized. § 178.58-21 Marking. (a) Marking on each container by stamping plainly and permanently only on a permanent attachment or on a metal nameplate permanently secured to the container by means other than soft solder, as follows: (1) DOT-4DA followed by the service pressure (for example, DOT-4DA900). (2) A serial' number and an identifying symbol (letters); location of number to be just below or immediately following the DOT mark; location of symbol to be just below or immediately following the number. The symbol and numbers must be those of purchaser, user, or maker. The symbol must be registered with the Bureau of Explosives; duplications unauthorized. The material used was identified by the following The container walls were measured and the minimum thickness noted was inch. The outside diameter was determined by a close approximation to be --inches. The wall stress was calculated to be pounds per square inch under an internal pressure of pounds per square inch. ------- ------- Hydrostatic tests, flattening tests, tensile tests of material, and other tests, as prescribed in specification No. DOT-4DA were made in the presence of the inspector and all material and containers accepted were found to be in compliance with the requirements of that specification. Records thereof are attached hereto. I hereby certify that all of these containers proved satisfactory in every way and comply with the requirements of Department of Transportation specification No. 4DA except as follows: Exceptions: (Signed) (Inspector) 39-022 0-74- -33 |