1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2013 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS4266 AEROSPACE STANDARD AS4266 Issued 2013-08 Superseding ARP4266 Hole Contour,
5、 Fluid Passage, Tube Fitting RATIONALE The previous version of this document, ARP4266, was intended to be a requirements document, but, since it was published as an ARP document, the contents are not mandatory, only recommended. Change to an SAE Aerospace Standard will make the specified contents ma
6、ndatory. Additionally, several of the figures are being revised to show the delineation requirements for drilled passages that are produced with traditional conical end drills. 1. SCOPE This SAE Aerospace Standard (AS) provides required contours and limits of size of the surfaces of the internal flu
7、id passages of tube fittings for the portions that are not already defined by the fitting end design standard drawings. 1.1 Purpose The internal passages of fittings are defined by: (1) the dimensions of the fitting end design standards, (2) a through hole diameter that may be smaller than that on t
8、he fitting ends, (3) an allowable offset of holes on the same axis, (4) a minimum wall thickness of the center body section of shape fittings, and (5) a requirement for a minimum ball to pass through shape fittings. This standard provides manufacturing requirements to reduce abrupt changes in contou
9、rs and thus minimize pressure drop, reduce the number of edges produced to minimize burrs and provide sufficient minimum size of fluid passages while maintaining a minimum wall thickness of the center body section, which is defined herein. The historical background of the need for this document is g
10、iven in 4.1. 2. REFERENCES The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict bet
11、ween the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 ASME Publications Available from ASME, 22 Law Drive, P.O. Box 2900,
12、 Fairfield, NJ 07007-2900, Tel: 800-843-2763 (U.S./Canada), 001-800-843-2763 (Mexico), 973-882-1170 (outside North America), www.asme.org. ASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay) SAE INTERNATIONAL AS4266 Page 2 of 10 3. REQUIREMENTS 3.1 Minimum Wall Thickness 3.1.1 For stra
13、ight fittings, such as unions, adapters, reducers, caps and plugs, the internal hole diameter and length should be specified with the hole ending in a conical end of 110 degree minimum included angle. A full spherical radius (SR) may be optional. If necessary a flat bottom may be specified. 3.1.2 Fo
14、r shape fittings, such as elbows, tees and crosses, a section thickness shall be specified as “Minimum wall thickness of center body section” as shown in Figure 1. FIGURE 1 - OPTIONAL CALLOUTS FOR MINIMUM WALL THICKNESS 3.1.3 The “center body section” is defined as that portion of the shape fitting
15、that is not dimensioned by the individual fitting end design standards except the internal passage hole may be the minimum hole from the design standard. See examples in Figure 2. FIGURE 2 - Examples of Center Body Sections of Shape Fittings SAE INTERNATIONAL AS4266 Page 3 of 10 3.2 Contours and Lim
16、its of Size of Internal Fluid Passages of Shape Fittings 3.2.1 The suggested sequence of production of the internal passage holes with their contours and limits of size for the four basic shapes, 90 degree elbow, 45 degree elbow, tee, and cross are shown in Figures 3 through 15. FIGURE 3 - 90 DEGREE
17、 ELBOW, NON-REDUCER (A1 = A2) FIGURE 4 - 90 DEGREE ELBOW, REDUCER (A B) SAE INTERNATIONAL AS4266 Page 4 of 10 FIGURE 5 - 45 DEGREE ELBOW, NON-REDUCER (A1 = A2) FIGURE 6 - 45 DEGREE ELBOW, REDUCER (A B) SAE INTERNATIONAL AS4266 Page 5 of 10 FIGURE 7 - TEE, NON-REDUCER OR REDUCER ON SIDE FIGURE 8 - TE
18、E, REDUCER ON RUN (A = C B) SAE INTERNATIONAL AS4266 Page 6 of 10 FIGURE 9 - TEE, REDUCER ON RUN (A C B) FIGURE 10 - TEE, REDUCERS ON RUN AND SIDE (A B; A C) SAE INTERNATIONAL AS4266 Page 7 of 10 FIGURE 11 - TEE, REDUCER ON BOTH RUNS (A B1; A B2) FIGURE 12 - CROSS, NON-REDUCER SAE INTERNATIONAL AS42
19、66 Page 8 of 10 FIGURE 13 - CROSS, REDUCER ON RUN ONLY (A1 = A2 = A3 B) FIGURE 14 - CROSS, REDUCER ON RUN AND SIDE (A = A B1 B2) SAE INTERNATIONAL AS4266 Page 9 of 10 FIGURE 15 - CROSS, REDUCER ON THREE SIDES (A B1 B2 B3) 3.2.2 The following notes also apply to each of the Figures 3 through 15: a. T
20、he spherical radius at the end of the hole shall be required on the larger diameter hole of elbows if pressure class is 5000 or greater (5000 psi nominal operating pressure or greater). All other shaped fitting passage holes may end in a spherical radius (preferred) or conical end (conical end of 11
21、0 degree minimum included angle). If conical end hole is used, the detail standard will require an “optional construction” delineation that also dimensions the depth of hole. The minimum wall thickness, as specified in Figure 1, shall also remain a requirement for conical end holes. b. The offset at
22、 mating holes on the same axis shall be 0.015 maximum. c. The minimum wall thickness of the fitting center body section shall be met. d. The surface texture of spherical or conical ends of holes shall be 250 microinches Ra per ASME B46.1. 4. NOTES 4.1 Background In 1951 the military standards for fl
23、areless fittings were published with specified drill depths for the fluid passage hole in each leg. In the late 1950s, fitting manufacturers issued company standards for flareless reducer fittings with formulas for the drill depth of fluid passage holes noted on each standard. These were often in co
24、nflict with airframe company and other manufacturers standards. In 1962, 37 degree flared reducer fitting standards were published by SAE Committee G-3B with formulas for the drill depths given on each standard. The parameters for these formulas were not well defined and calculations by various user
25、s often resulted in different dimensions. SAE INTERNATIONAL AS4266 Page 10 of 10 To avoid repeated calculations, flareless reducer fitting standards were published in 1966 by G-3B with tabulated tables of drill depths for each leg and for each reducer size. In 1983, calculated drill depth tables wer
26、e added to the flared reducer fittings by G-3B. Continued dimensional problems with some of the calculated drill depths were to be addressed with a 1984 G-3B project to prepare a proposed ARP4266 to specifically define how to calculate drill depths. In 1991, after long efforts by the project sponsor
27、, it was determined that it was not practical to specify formulas to calculate drill depths. It was agreed by G-3B to specify minimum wall thickness values for the center body section of shape fittings as necessary to meet the performance requirements specified for the fittings. At that time a separ
28、ate G-3B project resulted in a recommendation for the fluid passage hole as follows: “The contour at the bottom of the hole is optional; it may be curved or conical.” In 1994, G-3B agreed that to reduce pressure drop, a full radius round bottom in the hole intersection of elbows is desirable. This d
29、ocument is meant to address the above recommendations. In 2000, G-3B noted that since the recommendations specified in an ARP were considered not to be mandatory, ARP4266 is being converted into an AS standard, which will change the recommendations into requirements. 4.2 Dimensions All dimensions ar
30、e in inches. 4.3 A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY SAE SAE SUBCOMMITTEE G-3B, AEROSPACE FITTINGS OF COMMITTEE G-3, AEROSPACE COUPLINGS, FITTINGS, HOSE AND TUBING ASSEMBLIES
