1、AECMA PREN2998 - 6 L0123LL OOOi.1571 W -_ A. E. C. M .A. STAN DA RD pr EN 2998 NORME A.E.C.M.A. issue P 1 A.E.C.M.A. NORM June 1986 Edition approved for publication EDIT PAR LASSOCIATION EUROPEENNE DES CONSTRUCTEURS DE MATRIEL AEROSPATIAL 88, boutevard Malesherbes, 75008 PARIS -TEL. 45-63-82-85 Comm
2、ents should be sent within six months C3 Chairman after the date of publication decision UDC : Key words : ENGLISH VERSION Aerospace series Washers countersunk Heat resisting steel Srie arospatiale Rondelles fraises en acier rsistant chaud Luft- und Raumfahrt Scheiben angesenkt aus hochwarmfestem St
3、ahl 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 the manufacturers of the Member countries. Af
4、ter 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. 2 June 1986 A.E.C.M.A. 88, Bd. Malesherbes Mr ARENA 75008 PARIS - FRANCE aec
5、ma 1986 issue PI prEN2998 Page 3 1 Scope and field of application This standard specifies the characteristics of heat resisting steel countersunk washers for use in aerospace applications at temperature not exceeding 650 OC. They are intended primarily for use under the head of 12 point or spline dr
6、ive bolts with strength classification above or equal to 1250 MPa in order to apply the bearing load over a large area. 2 References EN2171 Heat resisting steel FE-PA 92 HT Rm 900 ma - Bars - Aerospace series EN2175 Heat resisting steel FE-PA 93 HT, solution treated and precipitation treated - Sheet
7、s and strips a 3 mm - Aerospace series EN2424 Identification marking of standard fasteners - Aerospace series EN2516 Aerospace series - Passivation of corrosion resisting steel 1). 3 Required characteristics 3.1. Configuration - Dimensions - Tolerances The configuration shall be in accordance with t
8、he figure ; the dimensions and tolerances shall conform to the values shown in the figure and in the table after passivation. 3.2. Surface roughness See Figure - The values apply before passivation. 3.3. Materials Steel EN2171 or EN2175. 3.4. Surface treatment Passivation EN2516 1) In preparation, P
9、revious page 0223MR0386T4 , is blank Diam Code Dl H13 nom Issue PI prEN2998 Page 4 90“ 2 5“ Break sharp edges 0,l to 0,2 Figure - Configuration Table - Dimensions and mass Dimensions in millimetres I I Mass i) kg/ 1000 pieces TO? . 0,72 1Y5 1,12 + c,3 - 2 1,85 080 I 8,2 I 16 2 2,07 100 I 1OY2 I 20,3
10、 l2 I 3,48 - + 0,4 2,5 5,63 7,06 26,9 16,2 31,1 11,30 19,2 1 + Gy5 - 12,48 2 23,: 7 d 15 ,SU i) Mass calculated on the bcsis of 7,851 kg/dm3 2) Flatness variatioris are incliied in the thickness tolerance. 0223MR03EBT4 Issue PI prEN2998 Page 5 4 Designation Each washer shall only be designated as in
11、 the following example : Identity b lock I Description block WASHER, COUNTERSUNK EN2998 - O - T O - Reference of EK standard I 080 : Diameter code (See table) Note : If necessary the originator Code S 9005 may be introduced between the description block and the identity block. 5 Marking EN2424 style G (Packaging). Ir! addition, the quantity shall be declared (mass er number. 0223bl0386T4
