1、MIL-C-24774 40 9999906 LLb0234 9b9 IINCH-POUND( MIL-C-24774(SH) 7 July 1992 MILITARY SPECIFICATION CHAIN, STUD LINK, ANCHOR, FLASH BUTT WELDED, NONMAGNETIC This specification is approved for use by the Naval Sea Systems Command, Department of the Navy, and is available for use by all Departments and
2、 Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers single shots (90-foot 1engt.s) of 3/4, Only one classification of chain is covered 7/8, 1, 1-1/8, and 1-1/4 inch, nonmagnetic, flash butt welded, stud link, anchor chain for use on mine warfare ships. by this speci
3、fication. 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Soecifications. standards. and handbooks. The following specifica- tions, standards, and handbooks form a part of this document to the extent speci- fied herein. Unless otherwise specified, the issues of these documents are those list
4、ed in the issue of the Department of Defense Index of Specifications anrd Standards (DODISS) and supplement thereto, cited in the solicitation (see 6.2). SPECIFICATIONS FEDERAL QQ-N-M - Nickel-Copper-Aluminum Alloy, Wrought (UNS N05500). TT -V- 5 1 - Varnish, Asphalt. MILITARY MIL-P-24441 - Paint, E
5、poxy-Polyamide, General Specification for. MIL-P-24441/1 - Paint, Epoxy-Polyamide Green Primer Formula 150, Type I. DOD-E-24635 - Enamel, Gray, Silicone Alkyd Copolymer Semigloss (for Exterior Use). (Metric) Beneficial comments (recommendations, additions, deletions) and any pertinent data which may
6、 be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 5523, Department of the Navy, 2531 National Center Bldg 3, Washington, DC 20362-5160 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end o
7、f this document or by letter. AMSC N/A FSC 4010 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. I Licensed by Information Handling ServicesMIL-C-24774 40 = 999990b 1160235 8T5 = MIL-C-24774(SH) MI LI TARY MIL-1-17214 - Indicator, Permeability; Low-Mu (Go-No Go). STA
8、NDARDS MILITARY MIL-STD-271 DOD-STD-2142 DOD-STD-2143 - Magnetic Silencing Requirements for the Construc- MIL-STD-45662 - Calibration Systems Requirements. - Requirements for Nondestructive Testing Methods. - Magnetic Silencing Characteristics Measurement of. (Metric ) tion of Nonmagnetic Ships and
9、Craft. (Metric) (Unless otherwise indicated, copies of federal and military specifications, standards, and handbooks are available from the Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.1.2 Other Government documents, drawings. and Dublication
10、s. The following other Government documents, drawings, and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation. PUBLICATIONS NAVAL SEX SYSTEMS COMMAND (NAVSEA) NAVSHIPS 0900-LP-003-8000 - Metals, Surface
11、 Inspection Acceptance Standards. (Application for copies should be addressed to the Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.2 Non-Government Dublications. The following document(s) form a part of this document to the extent specified he
12、rein. Unless otherwise specified, the issues of the documents which are DOD adopted are those listed in the issue of the DODISS cited in the solicitation. Unless otherwise specified, the issues of documents not listed in the DODISS are the issues of the documents cited in the solicitation (see 6.2).
13、 AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) A 370 - Standard Test Methods and Definitions for Mechanical E 381 - Standard Method of Macroetch Testing, Inspection, and Testing of Steel Products. Rating Steel Products, Comprising Bars, Billets, Blooms, and Forgings. (DoD adopted) (DoD adopted)
14、(Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) DET NORSKE VERITAS (DnV) Certification of Offshore Mooring Chain (Certification Notes No. 2.6). (Application for copies should be addressed to DET Norske Veritas,
15、 P.O. Box 300, N-1322 Hovik, Oslo, Norway.) 2 Licensed by Information Handling ServicesOd MIL-C-24774 40 9999906 LLb023b 731 130 75 20 32 (Non-Government standards and other publications are normally available from the organizations that prepare or distribute the documents. These documents also may
16、be available in or through libraries or other informational services.) O 120 70 15 24 2.3 Order of urecedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes appli
17、cable laws and regulations unless a specific exemption has been obtained. I 3. REQUIREMENTS I 3.1 First article. When specified (see 6.2), samples of chain shall be subjected to first article inspection (see 6.4) in accordance with 4.3. I 3.2 Material. Form 1 material (unaged, bar, rod, and forging)
18、 in the hot finished condition and conforming to QQ-N-286 shall be used in manufacturing the chain links and studs. The material used in normal production shall be the same composition as the material used in the first article sample in chemistry, quality, and properties. The chain material from eac
19、h mill run shall be identi- fied through the chain fabrication process. Unidentified material shall be considered nonconforming. 3.2.1 Material mechanical properties. Material properties shall be as specified in table I. Column A refers to bar stock material used in making the chain after receiving
20、a heat treatment identical to the chain heat treatment. Column B refers to material specimens taken from a typical chain link. TABLE I. Mechanical Droperties after heat treatment. I Property Column B link material I (minimum values) Column A bar stock (minimum values) Ultimate tensile strength (ksi)
21、 Yield strength (ksi) Elongation (percent) Reduction in area (percent) 3.2.2 Recovered materials. Unless otherwise specified herein, all materials incorporated in the products covered by this specification shall be new and may be fabricated using materials produced from recovered materials to the ma
22、ximum extent practicable without jeopardizing the intended use. The term “recovered materials“ means materials which have been collected or recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. None of the above shall be interpreted to me
23、an that the use of used or rebuilt products is allowed under this specification unless otherwise specifically specified. 3 Licensed by Information Handling ServicesMIL-C-24774 40 999990b LLb0237 b78 . 22-3/4 26 29 - 1/4 32-1/2 3.3 Link dimensions. Link dimensions and properties shall be as specified
24、 in table II and on figure 1 (see 6.2). III and on figure 2. deburred shall be as specified in table III. the link shall be symmetrical to ensure proper fit and function in the chain handling equipment. Tolerances shall be as specified in table Any flash trim overage existing after the flash butt we
25、ld is The grip radius (G) of each end of 23-1/16 26 - 3/8 29 - 5/8 32-15/16 Chain size (inches) 3/4 7/8 1 1- 1/8 1 - 1/4 Length A (inches) 4- 1/2 5 - 1/4 6 6 - 3/4 7 - 1/2 TABLE II. Stud link chain dimensions and DroDerties. - Minimum 19-3/8 22 - 5/8 25-7/8 29-1/16 32-5/16 _ Length over 6 links L (i
26、nches) 7- 19-1/2 19-3/16 Link width B (inches) 2 - 11/16 3 - 1/8 3 - 5/8 4 - 1/16 4 - 1/2 Numbe r of 1 inks Per shot 359 305 267 237 213 Proof test load (pounds) 39,600 53,900 70,400 89,100 110.000 Break test load (pounds ) .64,800 88,200 115,200 145,800 180,000 Minimum veight per 15- f athon shot (
27、pounds ) 520 705 920 1165 1435 Maximum weight per 15- f athon shot (pounds ) 563 765 1000 1270 1565 FIGURE 1. Stud link chain dimensions. 4 Licensed by Information Handling ServicesMIL-C-24774 40 m 7999906 l1160238 504 m MIL-C-24774(SH) Stud width (F) (H) plus minus 1/16 1/8 TABLE III. Stud link tol
28、erances. (GI plus or minus 1/16 Permissible tolerances (incl Nominal chain size (C) (inches) 3/4 to 1 - 1/4 (inclu- sive) Link length (A) plus or minus 1/16 Link width (BI plus or minus Wire di ame t e r ovality (maximum) I/ Maximum flash trim overage (D) 1/16 Stud centering or minus plus 3/16 I Gri
29、p radius - i/ When the link diameter (dimension C) is checked for ovality (major axis minus minor axis), the area of the elliptical cross section (n/4 x major axis x minor axis) shall be at least equal to the area of a circle of the chain size (n/4 x link diameter2). specified on figure 2. Dimension
30、 C shall be measured at a point generally as I -clcl- LEI I, I =OS X A FrO.75 X C 0 = 0.65 X C H = 2.0 x c FIGURE 2. Basic link and stud dimensions. 3.4 Link and stud surface. Burrs, irregularities, and rough edges shall be contour ground to a fair surface, surface irregularities, dents, and undercu
31、tting in excess of 1/16 inch when examined as specified in 4.5.2 and 4.7.3. inspection in the following areas: Links and studs shall also be free of cracks, Special attention shall be given to 5 Licensed by Information Handling ServicesNIL-C-24774 40 W 9999906 3360239 440 MIL-C-24774(SH) (a) Grip ar
32、ea while links interface during loading. (b) Region gripped by clamping dies during flash welding. (c) Flash weld buildup perimeter after trimming. Any ridge, flashing, or other projection in these areas shall be ground flush or blended with the fair link surface. 3.5 Flash butt weld. 3.5.1 Weld sur
33、face. The link surfaces at the flash weld shall be free of cracks, lack of fusion, and gross porosity when examined with liquid penetrant as specified in 4.5.3. 3.5.2 Fusion of weld ioint. The flash weld shall be free of defects causing ultrasonic (UT) back reflections equal to or greater than those
34、 produced from a 0.05-inch surface notch calibration standard, when tested as specified in 4.5.4. 3.5.3 Fusion zone microstructure. The heat-affected zones on each side of the weld joint shall be free of cracks when examined as specified in 4.5.8. 3.6 Stud size and alignment. Stud size and shape, al
35、ignment, and centering shall be as specified on figure 2 (see 4.5.7 and 4.7.12) and shall have no gaps visible between the stud and the link body at the ends of the H dimension. Noncontinuous gaps are permissible along the length H. 3.6.1 Stud Penetration. Prior to being pressed into the link body,
36、every stud must be free from unwanted protrusions and flash resulting from manufacturing or forging operations. Stud penetration (at midplane) into the link body resulting from the stud pressing process shall be so that a firm stud fit results; that is, no detectable looseness in any direction and s
37、hall be no more than 0.05C (C is the nominal chain size) maximum depth on either side of the link. Stud penetration shall be measured as specified in 4.5.5. The perimeter of the stud saddle shall be radiused (sharpness removed) to prevent cutting into the link body. 3.7 Link and stud interior. Links
38、 and studs shall be free from harmful defects such as laps, seams, pipes, cracks, fins, porosity, nonmetallic inclusions and segregation when examined as specified in 4.5.5 and 4.7.13. 3.8 Chain length. The chain shall be in 90-foot shots (15 fathoms) and consist of all common links, the quantity of
39、 which is specified in table II (see 6.2). The overall length of six consecutive links measured from every third link shall be within the limits specified in table II (see 4.5.1). By this method of measurement, every link, except three links at each end of the chain, shall be measured twice with dif
40、ferent combinations of adjacent links totaling six links (see 4.7.1). 3.9 Chain weight. The weight of each shot of chain shallbe in accordance with table II. The required weight limits of six-link samples shall be calculated from the information in table II. Weighing shall be done as specified in 4.
41、5.10. 3.10 Chain breaking load. The chain shall withstand the breaking load specified in table II and shall not crack in the flash butt weld, or the flash butt weld heat-affected zone, when tested as specified in 4.6.2. 6 Licensed by Information Handling ServicesMIL-C-24774 40 = 99999Ob LLb0240 Lb2
42、MIL-C-24774(SH) 3.11 Chain proof load. The chain shall withstand the proof load specified O in table II when tested as specified in 4.6.3. The actual load applied shall: (a) Not cause cracking, fracture, or deformation. (b) Not permanently increase chain length more than 1.7 percent or cause the cha
43、in to exceed the six-link and individual link dimensions. (c) (d) Not be applied more than three times. (e) Be used on a full shot or any portion thereof. Be recorded on strip charts along with the resulting elongation. 3.11.1 Chain sizing. Chain shall be sized (lengthened) to meet six-link length r
44、equirements by applying loads greater than the proof load (see 4.6.3 and 4.7.1) (see 6.3). 3.11.2 Maximum sizinp load. Sizing loads greater than 120 percent of the proof test load shall be cause for rejection of the entire shot (where a full shot is sized in one operation) or the affected links (whe
45、re fractions of a shot are sized in continuous production processes). 3.12 Chain DroDerties. Sample links detached from finished chain shall be sectioned and tested for determination of properties and bending characteristics (see 4.6.4, 4.6.5, 4.6.7, and 4.5.9). Mechanical properties shall be as spe
46、cified in table I. During bend testing, cracking or fracture shall not occur until the bend angle reaches 120 degrees when tested as specified in 4.6.5. The magnetic permeability (mu) of finished links shall be in accordance with DOD-STD-2143 and shall not exceed 1.2 mu using the test method PO1 of
47、DOD-STD-2142. shall be tested in accordance with DOD-STD-2142. Each shot 3.13 Standards of manufacture. Manufacture of the chain shall be as specified in 3.13.1 through 3.13.5. manufacture the first article inspection samples shall also be used for production chain (see 6.3). Equipment and processin
48、g parameters used to 3.13.1 Heating and bending. Bars shall be heated before bending using electric resistance heating. Peak bar temperatures shall not exceed 2100 degrees Fahrenheit (OF), Bending should be performed with bar temperatures above 1600 or below 900F. is to be avoided. Reheating of the
49、bar is permitted, but prolonged soaking at 2100F In order to prevent undue scaling or flaking of the bar due to excessive heat, the heating phase shall be automatically controlled by an optical heat sensor for electric resistance heating. least once every 8 production hours (see 6.3). The controller shall be checked for calibration at 3.13.2 Flash butt welding. The bent bar shall be electrically flash butt welded. meter. The bar ends shall be parallel within 5 degrees. Bar end misalignment Maximum bar end misalignment shall not exceed 5 percent of the bar dia- shall be checked a mini
