1、/INCH-POUNDI MIL-S-21427B(SH) 6 March 1989 SUPERSEDING 21 October 1960 (See 6.6) MIL-S-21427A(SHIPS) MILITARY SPECIFICATION STRAINER, ASSEMBLIES, MAIN STEAM, HIGH PRESSURE (SIZES 4 INCHES AND ABOVE) This specification is approved for use by the Naval Sea Systems Command, Department of the Navy, and
2、is available for use by all Departments and Agencies of the Department of Defense. . 1. SCOPE 1.1 Scope. This specification covers high pressure steam strainer assem- blies in sizes 4 inches and above intended primarily for main steam systems, for protection of power equipment and throttle valves fr
3、om dirt, sediment, pipe scale and foreign objects. 1.2 Classification. Strainer bodies shall be of the following compositions as specified (see 6.2.1): Composition A - 2-1/4 percent chromium, Composition B - 1-1/4 percent chromium, 1/2 Composition C - Carbon steel. 1 percent molybdenum alloy. percen
4、t molybdenum alloy. 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications and standards. The following specifications and standards form a part of this specification to the extent specified herein. Unless otherwise specified, the issues of these documents shall be those listed in th
5、e issue of the Department of Defense Index of Specifications and Standards (DoDISS) and supplement thereto, cited in the solicitation, Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander,
6、Naval Sea Systems Command, SEA 5523, Department of the Navy, Washington; DC 20362-5101 by using the self-addressed Standardization Docuinent Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A FSC 4730 DISTRIBUTION STATEMENT A. Approved for public release
7、; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-21427B 47 999990b 0273904 T MIL-S-21427B(SH) SPECIFICATIONS FEDERAL QQ-S-766 - Steel Plates, Sheets, and Strip-Corrosion Resisting. MILITARY MIL-G-21032 - Gaskets, Met
8、allic-Asbestos, Spiral Wound, STANDARDS MILITARY MIL-STD-129 - Marking for Shipment and Storage. MIL-STD-271 - Requirements for Nondestructive Testing Methods. MIL-STD-278 - Welding and Casting Standard. 2.1.2 Qther Government publication. The following other Government publica- tion forms a part of
9、 this specification to the extent specified herein. otherwise specified, the issues shall be those in effect on the date of the solicitation. Unless PUBLICATION NAVAL SEA SYSTEMS COMMAND (NAVSEA) NAVSHIPS 250-692-13 - Radiographic Standards for Steel Castings. (Copies of specifications, standards, a
10、nd publications required by contrac- tors in connection with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting activity.) 2.2 Other wbiications. The following documents form a part of this specification to the extent specified herein, U
11、nless otherwise specified, the issties of the documents which are DoD adopted shall be those listed in the issue of the DoDISS Specified in the solicitation. issues of documents not listed in the DoDISS shall be the issue of the non- government: documents which is current on the date of the solicita
12、tion. Unless otherwise specified, the AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) 316.5 - Pipe Flanges and Flanged Fittings, (DoD adopted) (Application for copies should be addressed to the American National Stan- dards Institute, 1430 Broadway, New York, NY 10018.) AMERICAN SOCIETY OF MECHANICAL E
13、NGINEERS (ASME) Boiler and Pressure Vessel Code, Sections I, II and VIII. (Applications for copies should be addressed to the American Society of Mechanical Engineers, 345 East 47th Street, New York, NY 10017.) AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) A 105 - Standard Specification for Forg
14、ings, Carbon Steel, for Piping Components. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-2ILI27B q7 999990b 0273905 I MIL-S-21427B(SH) ASTM (Continued) A 106 - Standard Specification for Seamless Carbon Steel Pipe for A 182 - Standard Speci
15、fication for Forged or Rolled Alloy-Steel High-Temperature Service. (DoD adopted) Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service, (DoD adopted) for Fusion Welding, for High-Temperature Service. (DoD adopted) Stainless and Alloy, for Pressure Containing Parts, Suitab
16、le for High-Temperature Service. Pipe for High-Temperature Service. A 216 - Standard Specification for Steel Castings, Carbon, Suitable A 217 - Standard Specification for Steel Castings, Martenistic (DoD adopted) A 335 - Standard Specification for Seamless Ferritic Alloy-Steel (Application for copie
17、s should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) UNIFORM CLASSIFICATION COMMITTEE AGENT Uniform Freight Classification Ratings, Rules and Regulations (Application for copies should be addressed to the Uniform Classification Committee
18、 Agent, Tariff Publication Officer, Room 1106, 222 South Riverside Plaza, Chicago, IL 60606.) (Nongovernment standards and other publications are normally available from the organizations which prepare or which distribute the documents. ments also may be available in or through libraries or other in
19、formational services.) These docu- 2.3 Order of precedence. In the event of a conflict between the text of this specification and the references cited herein (except for associated detail specifications, specification sheets or MS standards), the text of this speci- fication shall take precedence. N
20、othing in this specification, however, shall supersede applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 Material. Materials shall be as specified in table I. Material for parts other than those listed in table I shall be suitable for the intended pre
21、ssure and temperature. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-21427B 47 m 9499906 0273906 3 m MIL-S-21427B(SH) ASTM A 182, grade F-22 ASTM A 217, grade WC - 9 ASTM A 335, grade P-22 Name of part: Applicable documents ASTM A 182, ASTM
22、 A 105, grade F-11 grade 11 ASTM A 217, grade WC - 6 ASTM A 335, grade P-11 ASTM A 216, grade WCB ASTM A 106 Body, covers Welded bosses drain Gaskets - Nuts I bolts , washers TABLE I. Materials. Material form Forgings Cast ings Pipe Plate Spiral wound Composition A I Composition BI Composition c Mat
23、erial used in the construction of these parts shall be of the quality best suited for the purpose intended and shall be in accordance with the material specification shown on approved drawing. 3.1.1 Recovered materials. Unless otherwise specified herein, all equip- ment, material, and articles incor
24、porated in the products covered by this specifi- cation shall be new and may be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing the intended use. The term “recovered materials“ means materials which have been collected or recovered
25、from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. that the use o used or rebuilt products is allowed under this specification unless otherwise specifically specified. None of the above shall be interpreted to mean 3.2 Construction. The strainer
26、 assemblies shall be composed of a body with blet connections, closure, strainer basket assembly, bosses for installation of thermometers and either a single or dual outlet as specified (see 6.2.1). In no caso shall the basket assembly be permanently attached to the end closure. strainer body inlet
27、or outlet connections are welded, they shall be limited to 1/2 tho size of the strainer body for services 600 pounds per square inch (lb/in2) and above or 425 degrees Fahrenheit (OF) and above. Where 3.2.1 Pressure temperature ratings. The strainer bodies shall be in accordance with ASME Boiler and
28、Pressure Vessel Code, sections I, II and VIII, as applicable. pressure and the design temperature shall be 10F plus maximum system temperature (see 6.2.1). The design pressure shall be equal to 1.05 times maximum system 3.2.2 Temperature ratings. The maximum allowable temperatures for strainers spec
29、ified herein shall be as follows: (a) Composition A - io50 (b) Composition B ,. 1000F (c) Composition C - 775F 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-2lLi27B Li7 W 7999906 0273907 5 MIL-S-21427B(SH) 3.2.3 Sizes. The sizes of strainer
30、 assemblies, number of inlets and outlets and their sizes, and whether straight, wye, angle, or manifold shape shall be as specified (see 6.2.1). 3.2.4 Strainer baskets. Strainer baskets shall be made of drilled plate. The welded seam shall not be drilled. be at least 2 times the inlet pipe area. Th
31、e plate shall have 3/32-inch maximum drilled openings. The strainer basket shall be strong enough to prevent failure in case it is plugged, a sufficient amount to produce a pressure drop across the basket equivalent to 25 percent of the working pressure, The wall thickness for the strainer basket sh
32、all be determined from the formula as specified in section VI11 of ASME Boiler and Pressure Vessel Code, In no case shall the wall thickness be less than 1/4 inch. The ligaments between the perforations shall be determined from the formula as specified in section I of ASME Boiler and Pressure Vessel
33、 Code. The ligament efficiency shall be not less than 30 percent and not more than 50 percent. The holes in the basket shall be so arranged that the maximum continuous unperforated area is in a transverse or circumferential direction. The welded seam of the strainer basket shall not be located in th
34、e direct line of the main steam flow through the strainer, The net open area through the basket shall 3.2.5 Fabrication. Welding shall be in accordance with MIL-STD-278. 3.2.6 End connections. Unless otherwise specified (see 6.2.1), end connec- tions shall be butt welding ends prepared in accordance
35、 with ANSI B16.5. flanged strainer assemblies, flanges in accordance with ANSI B16.5 shall be specified (see 6.2.1). Flange faces, when flanges are specified, shall be of a finish with a circular lay (concentric or phonographic) having a roughness not exceeding 500 roughness height rating (RHR) prod
36、uced by machining cuts of 0.003 inch maximum depth with not less than 40 cuts per inch of face width. installations involving radioactive service or hazardous fluids (toxic or explo- sive) where a finer finish is required, the requirements shall be the same except that the finish shall be 125 RHR ma
37、ximum. cannot be turned and tool marks run across the flange face, the surface finish shall have a maximum RHR of 125. For For special For flanges where the flange face 3.2.7 End closure. End closure shall be flanged. 3.2.8 Drain connections. Each strainer shall be provided with a drain connection.
38、drainage of the strainer. The drain connection shall be so located as to permit adequate 3.2.9 Steam flow. Unless otherwise specified (see 6.2.1), the strainer shall be constructed so that the steam flow through the strainer basket is from the inside of the basket to the outside of the basket, 3.2.1
39、0 Interchangeability. In no case shall parts be physically inter- changeable or reversible unless such parts are also interchangeable or reversible with regard to function, performance and strength. 3.3 Marking. Strainer bodies shall have the pressure rating and manufac- turers name or trademark cas
40、t or forged integral with the strainer body. No metal stamping shall be permitted on the finished strainer bodies or surfaces subjected to high stresses in service. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MLL-S-2LY27B 47 W 79979Ob O273908 7 3
41、.4 Drawinas. When specified in the contract or order, drawings shall be prepared (see 6,2.2 and appendix). 4. QUALITY ASSURANCE PROVISIONS 4.1 Resnonsibilitv for inspection. Unless otherwise specified in the contract or purchase order, the contractor is responsible for the performance of all inspect
42、ion requirements as specified herein. the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the Government. The Government reserves the right to perform any of the ins
43、pections set forth in the specification where such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. Except as otherwise specified in 4.1.1 Rasnoncibility for compliance. All items must meet all requirements of sections 3 and 5. The inspection set f
44、orth in this specification shall become a part o% the contractors overall. inspection system or quality program. absence of any inspection requirements in the specification shall not relieve the coneraceor of the responsibility of assuring that all products or supplies submitted to the Government fo
45、r acceptance comply with all requirements of the contract. Sampling in quality conformance does not authorize submission of known deective material, either indicated or actual, nor does it commit the Government to acceptance of defective material, The 4.2 Non-destructive insnection. 4.2.1 Vi.sua1 an
46、d-dimensional examination. Each strainer shall be visually and dimensionally examined to verify conformance with all the requirements of this speciicatioii not involving tests , 4.2.2 Radioaraahic inspection. Pressure containing castings and flanges of strainers shall be 100 percent radiographically
47、 inspected. Inspection shall be in accordance with MIL-STD-271 and NAVSHIPS 250-692-13. Sections less than 1 inch in thickness shall meet class 1 requirements of NAVSHIPS 250-692-13. Sections with thickness 1 inch and over shall meet class 2 requirements of NAVSHIPS 250-692-13. Flanges shall maet th
48、e class 2 requirements of NAVSHIPS 250-692-13. 4.2.3 Mametic particle. Pressure containing forgings of strainers shall be 100 percent magnetic particle inspected in accordance with 4.2.2. be free from flaws such as seams, cracks, laps, porosity, scale, flakes, and all other defects detrimentally aff
49、ecting the suitability of the forgings for the service intended. Forgings shall 4.2.4 Defects to be repaired. inspected in accordance with 4.2.3: The following shall apply to those parts (a) Defects less than 0.030 inch in depth need not be repaired provided the bottom of the defect is rounded and visible and the minimum wall thickness is maintained. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-2LL
