1、CEN PRENJ367b 93 = 3404589 004b773 bL4 = AECMA STANDARD NORME AECMA AECMA NORM prEN 3676 Edition P 1 June 1993 EDITE PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATERIEL AROSPATIAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cedex - Tl. (1) 47.36.98.76 UDC : Descri
2、ptors : Srie arospatiale Douilles filetes, paroi mince Norme de conception ENGLISH VERSION Aerospace series Inserts, thin wall Design standard Luft- und Raumfahrt Gewindeeinstze, dnnwandig Konstru ktionsnorm This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (Ass
3、ociation Europenne des Constructeurs de Matriel Arospatial). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee folio wing comment by the Member countries. Subsequent to the publication of this prestanda
4、rd, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Mem
5、ber countries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. Nota - Extra copies can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau - 921 38 ISSY-LES-MOULINEAUX CEDEX should be sent within six months after
6、 the date of publication to Edition approved for publication C8 Chairman 1993-06-30 AECMA Technopolis - 175, rue Jean-Jacques Rousseau 921 38 Issy-les-Moulineaux Cedex - FRANCE Mr. Williams aecma 199: CEN PREN*3676 93 3404589 O046774 550 1 Scope prEN 3676 Page 3 This standard specifies the design pr
7、actices for the application, broaching and tapped hole information for the EN standard aerospace series of thin wall self-locking, metric threaded inserts. 2 Normative references IS0 5855-1 Aerospace - MJ threads - Part 1 : General requirements EN 3236 Aerospace series - Inserts, thin wall, short, i
8、n heat resisting nickel base alloy NI-P1 OOHT (Inconel 71 8) l) EN 3237 Aerospace series - Inserts, thin wall, long, in heat resisting nickel base alloy NI-P1 OOHT (Inconel 71 8) EN 3298 Aerospace series - inserts, thin wall - Installation and removal procedure l) EN 3916 Aerospace series - Inserts,
9、 thin wall - Non-conformance procedure for components using salvage 2) 3 Description 3.1 both internally and externally, with an externally serrated upper portion. A self-locking thin wall insert as shown in figure 1 is a sleeve of metal which is threaded 3.1.1 These inserts are screwed into the thr
10、eaded hole which contains a counterbore (see clause 7) and are fixed by swaging the serrated portion of the insert into the counterbore (see figures 2 and 3) thus fixing the insert into the parent component and preventing the inserts movement during the installation or removal of a bolt. 3.1.2 The s
11、elf-locking feature of these inserts is positioned approximately at the mid point of the internal threaded portion. 3.1.3 These inserts will be silver coated only on their internal threaded portion. Serrated portion Driving Figure 1 1) Published as AECMA Prestandard at the date of publication of thi
12、s standard 2) In preparation at the date of publication of this standard Previous page is blank CEN PRENx3676 93 3404589 0046775 497 prEN 3676 Page 4 4 Application 4.1 Thin wall self-locking inserts may be used in blind and open ended tappings. 4.2 1. The assembled insert is suitable for use with me
13、tric bolts with MJ threads to IS0 5855- 4.3 Typical examples of installed inserts are illustrated in figures 2 and 3 (see also clause 9). bolt length shall be such as to ensure full thread engagement with the insert. Figure 2 Figure 3 4.4 light alloys through to corrosion and heat resisting steels a
14、nd titanium alloys. These metric thin wall inserts may be used in various types of materials ranging from 4.5 alloys and are installed into a threaded hole which contains a serrated counterbore. Short inserts (EN 3236) are used in hard materials such as steel, nickel and titanium Long inserts (EN 32
15、37) are used in softer materials such as light alloys and are installed into a threaded hole with a plain counterbore. 4.6 These inserts are fixed by swaging their upper serrated portion into a counterbore in the parent components. When used in the harder materials such as corrosion and heat resisti
16、ng steels, titanium alloys, etc., serrations shall be provided in the counterbored portion to enable a satisfactory installation, see 7.2 for details. 4.7 tooling. Sufficient access shall be provided to permit the use of both installation and extraction 5 Insert lengths 5.1 on application), each hav
17、ing its own part number range as given in table 1. There are two lengths of inserts, a short one and a long one (selection being dependent CEN PRENs3b76 93 3404589 004b77b 323 Bolt thread Short Length diameter inserts f 0.30 prEN 3676 Page 5 Long Length inserts f 0.30 5.2 The minimum flange thicknes
18、s dimension “F“ given in table 3 is less than the insert lengths given in table 1. When using these minimum flange thicknesses, protrusion of the insert will occur. Designers shall therefore ensure that the insert does not protrude into an abutment face, or foul any other adjacent features. MJ5x0,8
19、MJ6xl MJ7xl Table 1 EN3236-050 7,60 EN3237-050 13,15 EN3236-060 8,90 EN3237-060 15,35 EN3236-070 10,90 EN3237-070 17,75 MJ8xl MJ1 Oxl,25 EN3236-080 12,80 EN3237-080 20,15 EN3236-1 O0 16,20 EN3237-1 O0 24,85 Bolt thread diameter 5.2.1 The minimum flange thickness has been calculated to provide suffic
20、ient insert thread engagment, to ensure the insert does not creep, when its mating fastener is tightened. Locking torque Nm 6 Performance and material MJ8xl MJlOx1,25 6.1 temperature of 550 OC. The thin wall inserts called up in table 1 have a minimum performance of 25 re-uses at a 0,65 6,O 1,20 9,s
21、 NOTE : Temperature limitations may depend on the operational temperature limits of the parent material into which an insert has been installed. 6.1.1 used at lower temperatures. It should be noted that there will be a progressive increase in the insert re-usability when 6.2 required to achieve the
22、minimum re-usuability performance given in 6.1 . The self-locking torque values for these inserts are given in table 2. These are the values Table 2 min. MJ5x0,8 MJ6xl MJ7xl 0,50 CEN PRENx3bb 93 3404589 0046777 2bT prEN 3676 Page 6 7 Hole preparation 7.1 thin wall inserts. Table 3 and figure 4 provi
23、de the necessary information for the tapped holes to receive 7.1.1 The counterbore depth “DI“ applies when inserts are to be installed into light alloy components and pre-broaching is not required. Counterbore “D,“ applies when inserts are to be installed into hard materials, .e. steels, nickel and
24、titanium alloys and the counterbore will need to be pre-broached. 7.1.2 Dimension “E“ is the minimum recommended boss thickness. Designers shall review these minimum thicknesses in respect to the components application and its methods of manufacture, e.g. casting, forging or fully machined, as this
25、may affect these minimum recommendations. The minimum dimensions for “E“ from table 3 do not make any allowances for salvage. If salvage is to be an important consideration, provision will need to be made during the design phase of the component and dimension “E“ shall be used, increased accordingly
26、 and the minimum values quoted in table 6. 7.2 Figure 5 and table 4 give the additional information required to produce the serration in the counterbore for steel, nickel, and titanium alloys. These serrations are produced using a special broaching tool (see clause 7.3). Thread marks on RO I25 Threa
27、d diameter “A“ modified minor diameter - to tap drill diameter “B“, e.g. MJ7xl-4H5H MOD MINOR DIA 6,03-6,13 (see 7.2) “E min.“ after final min. 2,00 after finai 1 machining see 7.1.2) Thread pitch diameter U Figure 4 CEN PREN*3bb 73 m 3404587 0046778 LTb m prEN 3676 Page 7 Table 3 - Dimensions (see
28、figure 4) Dimensions in millimetres Table 3 (continued) Dimensions in millimetres Table 3 (concluded) Dimensions in millimetres r Insert EN3237 series (long) I CEN PREN*3b7b 93 W 3404589 O046779 032 W Bolt thread diameter prEN 3676 Page 8 K L Depth Number of serrations Major diameter of serrations M
29、J5x0,8 “D,“ table 3 7.1.1 max. min. 2,65 2,02 18 R 0,25 max. MJ6xl MJ7xl MJ8xl MJ10x1,25 “L“ serrations to EN 3298 to be broached in counterbore, using a “wobble broach“ with the cutting tool offset by 1 O to the broaching tool body. 2,75 2,12 24 3,05 2,42 27 3,25 2,62 28 3,65 3,02 33 .Thread pitch
30、diameter Figure 5 Table 4 CEN PRENu367b 93 3404589 0046780 854 prEN 3676 Page 9 7.3 tool, figure 6 gives the rcir,-inm !:*.2;?;!: tool parameters to be catered for. Sufficient space shall be provided around each hole to allow access for the broaching Dimensions in millimetres rnax. 0 37,OO Clearance
31、 min. 2,OO Figure 6 8 Installation restrictions 8.1 In applications where it is necessary to pass components through the assembled insert care shall be taken to ensure that such components do not foul the locking feature inside the insert. The maximum diameter mandrel that can be passed through the
32、insert is illustrated in figure 7 and dimensions are given in table 5. Figure 7 Table 5 Bolt thread diameter max. MJ5x0,8 MJ6xl MJ7xl MJ8xl MJlOx1,25 I 6,64 I max. 0 X I CEN PRENx3b76 93 3404589 0046783 790 prEN 3676 Page 10 9 Installation specification 9.1 to be used for installing the metric self-
33、locking thin wall inserts, given in table 1. EN 3298 provides the necessary serration dimensions, instructions and installation tools 9.2 component. For an example of Engineering Drawing callout, see figure 8. Inserts shall be screwed between 0,40 mm and 0,65 mm below the surface of the parent Insta
34、ll insert 0,40 mm to 0,65 mm below the surface in accordance with EN 3298 Figure 8 10 Provisions for salvage 10.1 When thin wall inserts are selected for a design, consideration shall be given to the feasibility of salvage where the original holehsert could be damaged during manufacture, or where th
35、e hole is machined out of position. 10.2 Before provision is made for salvage, consideration shall be given to component cost/weight requirements, e.g. for an inexpensive component salvage may not be an economic proposition, whereas an expensive component may necessitate salvage. Where provision for
36、 salvage is made the component will be heavier because of the increase in wall section around the threaded holes. CEN PRENx3676 93 3404589 0046782 627 Bolt thread diameter prEN 3676 Page 11 S min. S min. T for salvage of for salvage of Thread short inserts long inserts (references) S min. S min. 10.
37、3 When a decision has been made to make salvage a design consideration the minimum boss radii dimensions (“E“) instructed by 7.1.2 and quoted in table 3 will need to be increased to the dimensions (“S“) given in table 6 (see figure 9). MJ6xl MJ7xl MJ8xl MJ1 Oxl,25 10.4 Reference should be made to EN
38、 391 6 on how to instruct the relevant salvage technique. 7,OO 8,OO MJ101-4H5H 7,50 8,50 MJ 1 1 xl-4H5H 8,OO 9,00 MJ121-4H5H 9,00 10,oo MJ141-4H5H Table 6 10.5 shall be in accordance with EN 3916. In the event of salvage action, hole preparation, salvage insert selection and assembly Figure 9 “S min
39、.“ after final machining 11 Designation EXAMPLE : Identity block EN3676-050 Diameter code (see table 3) Number of this standard O CEN PRENa3676 93 3404589 0046783 563 prEN 3676 Page 12 12 Indication on drawings 12.1 See example on figure 10. Long insert EN 3237 series in soft materials (plain counte
40、rbore) 2,75 mm 2,50 mm INSERT HOLE EN3676-060 Figure 10 12.2 See example on figure 11. Short insert EN 3236 series in hard materials (serrated counterbore) Dimensions in millimetres Major diameter I a#,151 A 2,75 of serrations 24 serrations to EN 3298 INSERT HOLE EN 3676-060 Thread pitch - diameter Figure 11 Alternatively the insert holes may be fully dimensioned on the drawing. - CEN PRENx367b 93 m 3404589 OOqb78Y 4TT m prEN 3676 Page 13 12.3 Installation See example on figure 12. Figure 12 IN SERT EN323 6-060 assembled to EN 3298
