Specifications

4B240ET;

§ 78.55 welded and brazed cylinders made from electric resistance welded tubing. [Order 25, 21 F. R. 3014, May 5, 1956]

§ 78.55-1 Compliance. (a) Required in all details.

§ 78.55-2 Type, spinning process, size and service pressure-(a) Type. Cylinders must be of brazed type made from electric resistance welded tubing which has been certified by the tubing manufacturer that each length of tubing has been pressure tested to a fiber stress of 24,000 pounds per square inch, as calculated by the formula

(b) Spinning process. Cylinders closed in by spinning process authorized.

(c) Size. The maximum water capacity of this type shall not exceed 12 pounds or 333 cubic inches. The maximum outside diameter of the shell shall be five inches and maximum length of shell 21 inches.

(d) Service pressure.1 Must be 240 pounds per square inch.

[15 F. R. 8372, Dec. 2, 1950, as amended by Order 1, 16 F. R. 5328, June 6, 1951; Order 25, 21 F. R. 3014, May 5, 1956]

§ 78.55-3 Inspection by whom and where. (a) By competent inspector; chemical analyses and tests, as specified,

The "service pressure" limits the use of the cylinder. It is shown by marks on cylinder; for example, ICC-4B240ET indicates the service pressure as 240 pounds per square inch.

to be made within limits of the United States. Interested inspectors are authorized.

§ 78.55-4 Duties of inspector. Inspector shall: (a) Inspect all material and reject any not complying with requirements; for cylinders made by billetpiercing process, billets to be inspected after nick and cold break.

(b) Verify chemical analysis of each heat of material by analysis or by obtaining certified analysis: Provided, That a certificate from the manufacturer thereof, giving sufficient data to indicate compliance with requirements, is acceptable when verified by check analyses of samples taken from one cylinder out of each lot of 200 or less.

(c) Verify compliance of cylinders with all requirements including markings; inspect inside before closing in both ends; verify heat treatment as proper; obtain samples for all tests and check chemical analyses; witness all tests; verify threads by gauge; report volumetric capacity and tare weight (see report form) and minimum thickness of wall noted.

(d) Render complete report (§ 78.5522) to purchaser, cylinder maker, and the Bureau of Explosives.

Plain

§ 78.55-5 Steel. (a) Open hearth or electric steel of uniform quality. carbon steel content percent for the following not over: carbon, 0.25; phosphorus, 0.045; sulfur, 0.050. The addition of other elements for alloying effect is prohibited.

§ 78.55-6 Identification of material. (a) Required; any suitable method.

§ 78.55-7 Defects. (a) Material with seams, cracks, laminations, or other injurious defects, not authorized.

(a) By best § 78.55-8 Manufacture. 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 cylinder appreciably; reasonably smooth and uniform surface finish required. Heads may be attached to shells by lap brazing or may be formed integrally. The thickness of the bottom of cylinders welded or formed by spinning is, under no condition, to be less than two times the minimum wall thickness of the cylindrical shell; such bottom thicknesses to be measured within an area

bounded by a line representing the points of contact between the cylinder and floor when the cylinder is in a vertical position. Seams must be made as follows:

(b) Circumferential seams: By brazing only. Heads attached to shells by the lap brazing method shall overlap not less than four times wall thickness. Brazing material shall have a melting point of not less than 1000° F. Heads must have a driving fit with the shell unless the shell is crimped, swedged, or curled over the skirt or flange of the head and be thoroughly brazed until complete penetration of the joint by the brazing material is secured. Brazed joints may be repaired by brazing.

(c) Longitudinal seams in shell: Electric resistance welded joints only. No repairs to longitudinal joints permitted. § 78.55-9 Welding or brazing. (a)

The attachment to the tops and bottoms only of cylinders by welding or brazing of neckrings, footrings, handles, bosses, pads, and valve protection rings is authorized provided that such attachments and the portion of the container to which they are attached are made of weldable steel, the carbon content of which must not exceed 0.25 percent.

§ 78.55-10 Wall thickness. (a) The wall stress at two times service pressure shall not exceed 18,000 pounds per square inch. Minimum thickness shall be 0.044 inch.

(b) Calculation must be made by the formula:

a fitting, boss, or pad, securely attached to cylinder by brazing or by welding or by threads. Fitting, boss, or pad must be of steel suitable for the method of attachment employed, and which need not be identified or verified as to analysis, except that if attachment is by welding, carbon content must not exceed 0.25 percent. If threads are used, they 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.

(3) Straight threads, having at least 4 engaged threads, to have tight fit and calculated shear strength at least 10 times the test pressure of the cylinder; gaskets required, adequate to prevent leakage.

(b) Closure of fitting, boss, or pad must be adequate to prevent leakage.

§ 78.55-13 Safety devices and protection for valves, safety devices, and other connections, if applied. (a) Devices

must be as required by the Interstate Commerce Commission's regulations that apply (see §§ 73.34 (f) and 73.301 (i) of this chapter).

§ 78.55-14 Hydrostatic test. (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) Cylinders must be tested as follows:

(1) Each cylinder; to at least 2 times service pressure.

(2) Or, 1 cylinder out of each lot of 200 or less; to at least 3 times service

pressure. Others must be examined under pressure of 2 times service pressure and show no defect.

(e) Each 1000 cylinders or less successively produced each day shall constitute a lot. One cylinder shall be selected from each lot and hydrostatically tested to destruction. If this cylinder bursts below five times the service pressure, then two additional cylinders must be selected and subjected to this test. If either of these cylinders fails by bursting below five times the service pressure, then the entire lot must be rejected. All cylinders constituting a lot shall be of identical size, construction, heat-treatment, finish, and quality.

(a) Be

§ 78.55-15 Flattening test. tween knife edges, wedge shaped, 60° angle, rounded to 1⁄2" radius; test 1 cylinder taken at random out of each lot of 200 or less, after hydrostatic test.

78.55-16 Physical test. (a) To determine yield strength, tensile strength, elongation, and reduction of area of material. Required on 2 specimens cut from 1 cylinder, or part thereof heattreated as required, taken at random out of each lot of 200 or less in the case of cylinders of capacity greater than 86 cubic inches and out of each lot of 500 or less for cylinders having a capacity of 86 cubic inches or less.

(b) 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 316 inch thick. The specimen, exclusive of grip ends, must not be flattened. Grip ends may be flattened to within one inch of each end of the reduced section. When size of cylinder does not permit securing straight specimens, the specimens may be taken in any location or direction and may be straightened or flattened cold, by pressure only, not by blows; when specimens are so taken and prepared, the inspector's report must show in connection with record of physical tests detailed information in regard to such specimens. Heating of specimen for any purpose is not authorized.

(c) The yield strength in tension shall be the stress corresponding to a permanent 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 E8-42.

(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 % inch per minute during yield strength determination.

[15 F. R. 8372, Dec. 2, 1950, as amended by Order 4, 17 F. R. 1564, Feb. 20, 1952]

§ 78.55-17 Acceptable results for physical and flattening tests. (a) Elongation at least 40 percent for 2 inch gauge length or at least 20 percent in other cases; yield strength not over 73 percent of tensile strength; flattening test required, without cracking, to six times wall thickness with weld 90° from direction of applied load. Two rings cut from the ends of length of pipe used in production of a lot may be used for flattening test provided the rings accompany the lot which they represent in all thermal processing operations. At least one of the rings must pass the flattening test. § 78.55-18 Leakage test. (a) All spun cylinders and plugged cylinders (see Notes 1 and 2) must be tested for leakage by gas or air pressure after the bottom has been cleaned and is free from all moisture. Pressure, approximately the same as but no less than service pressure, must be applied to one side of the finished bottom over an area of at least 16 of the total area of the bottom but not less than 34" in diameter, including the closure, for at least 1 minute, during which time the other side of the bottom exposed to pressure

must be covered with water and closely examined for indications of leakage. Leakers must be rejected. (See § 78.5519 (a) (1).)

NOTE 1: A spun cylinder is one in which an end closure in the finished cylinder has been welded by the spinning process.

NOTE 2: A plugged cylinder is one in which a permanent closure in the bottom of a finished cylinder has been effected by a plug.

NOTE 3: As a safety precaution, if the manufacturer elects to make this test before the hydrostatic test, he should design his apparatus so that the pressure is applied to the smallest area practicable, around the point of closure, and so as to use the smallest possible volume of air or gas.

§ 78.55-19 Rejected cylinders—(a) Repairs authorized. Leakers must be rejected, except that:

(1) Spun cylinders rejected under the provisions of § 78.55-18 may be removed from the spun cylinder category by drilling to remove defective material, tapping, and plugging.

(2) Brazed joints may be rebrazed.

(3) Subsequent to the operations noted above in subparagraphs (1) and (2) of this paragraph, acceptable cylinders must pass all prescribed tests.

§ 78.55-20 Marking. (a) Marking on each cylinder by stamping plainly and permanently on shoulder, top head, neck or valve protection collar which is permanently attached to the cylinders and forming an integral part thereof, provided that cylinders not less than 0.090 inches thick may be stamped on the side wall adjacent to top head, as follows: (1) ICC-4B240ET.

1 Lot numbers, not over 500 cylinders in each lot, authorized for cylinders not over 2 inches outside diameter and for cylinders over 2 inches outside diameter when the volumetric capacity does not exceed 60 cubic inches.

2 Symbol in front of or following the number with ample space between or symbol and serial number stamped into welded or brazed-on valve spud directly above the ICC specification mark located on head of cylinder are also authorized. Other variations in location authorized only when necessitated by lack of space.

Example: ICC-4B240ET

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