1、ENGLISH VERSION Comments should be sent within six months after the date of publication decision Edition approved for publication Aerospace series Washers, flat, large diameter aluminium alloy C3 Chairman Srie arospatiale Rondelles plates larges, en alliage daluminium Luft- und Raumfahrt Scheiben, a
2、ngesenkt, groer Aupendurchmesser aus Aluminium This standard is initially published on green paper for the needs of AECMA-Members (Association Europenne des Constructeurs de Matriel Arospatial). It has been technically approved by the experts of the concerned AECMA Commission following comment by th
3、e manufacturers of the Member countries. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be published in its final version on yellow paper as an AECMA Standard. Mr ARENA I A.E.C.M.A. 88, Bd. Mal
4、esherbes I 22 April 1986 I 75008 PARIS - FRANCE I AECMA PREN2912 8b 1012311 0007050 b = Issue P 1 prEN2912 Page 3 I Scope and field of application This standard specifies the characteristics of aluminium alloy flat washers with a large outside diameter (3 X inside diameter approx.) for use in aerosp
5、ace.applications, at temperatures below 120 OC. They are intended for use with soft materiais to spread the bearing loads, and avoid surface damage. 2 References EN2090 EN2091 EN21 O1 EN23 1 9 EN2320 EN2424 , Aluminium alloy 2024-T3 P1 - Clad sheets and strips, 0,4 A 6 mm - Aerospace , Aluminium all
6、oy 2024-T4 P1 - Clad sheets and strips, 0,4 A 6 mm - Aerospace , Aerospace series - Chromic acid anodicing of wrought aluminium alloys 1) , Aluminium alloy 2024-T351 O - Drawn bars A 75 mm - Aerospace series , Aluminium alloy 2024-T4 - Drawn bars A 75 mm - Aerospace series , Identification marking o
7、f standard fasteners - Aerospace series series series 3 Required characteristics 3.1 Configuration - Dimensions - Tolerances Configuration shall correspond with the figure ; dimensions and tolerances shall correspond to figure and table after chromic anodising. 3.2 Surface roughness The values shown
8、 in the figure apply prior to chromic anodising. 3.3 Materials Aluminium alloy EN2090 or EN2091 or EN231 9 or EN2320. 3.4 Surface treatment Chromic acid anodising EN21 O1 with sealing. 1) In preparation. AECMA PREN2912 Bb W 1012311 0007051 B W 0,6 I 06 issue P 1 prEN2912 Page 4 0,09 1 0,6 10 0,16 06
9、 0,17 1 1 10 0,28 10 0,44 12 13 12 0,76 16 1 ,o1 12 1,6 12 1 ,o0 16 1,33 23 2 25 4,37 20 5,05 23 25 6,30 Break all corners 0.1 to 0.2 mm Figure - Configuration Table - Dimensions and tolerances Dimensions in millimetres Mass kg/l O00 pieces approx. 2) s 1) Thickness &IO% I code Diameter code dl HI3
10、d2 hl 4 d3 32 9 030 040 +o, 1 O 4,2 12 050 15 52 6 16 0,70 060 62 18 7,4 21 070 080 1 O0 120 +0,2 O -y+-+ 3,49 24 30 36 9,4 11,6 13,8 +0,3 O 1) Flatness variations are included in the thickness tolerance. 2) Calculated on the basis of 2,85 kg/dms. AECMA PREN2912 86 m 1012311 0007052 T - m _ - - / Is
11、sue P 1 , prEN2912 Page 5 , 4 Desig-nation Each wwher shall only be designated as in the following example : / Description block WASHER Identity block EN291 2-08020 080 = diameter code (see table) Number of EN standard 20 = thickness code (see table) I Note : if necessary, the originator code S9005 may be introduced between the description block and the identity block. 5 Marking EN2424, style G. In addition to the quantity shall be stated (Mass or number).
