1、STD-AECMA PREN q255-ENGL 1777 E LO12311 001217b 720 Edition approved for publication AECMA STANDARD NORME AECMA AECMA NORM Comments should be sent within six months after the date of publication to C3 Chairman prEN 4255 Edition P 1 January 1997 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDU
2、STRIES (AECMA) Guliedelle 94 - 8-1200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : 49.040.20 Descriptors : ENGLISH VERSION Aerospace series Nuts, anchor, self-locking, fixed, two lug, with counterbore, in heat resisting steel, silver plated Classification : 1 100 MPa (at ambient t
3、emperature) / 425 OC Srie arospatiale crous river, freinage interne, fixes, double patte, avec chambrage, en acier rsistant chaud, argents Classification : 1 100 MPa ( temprature ambiante) I425 OC Luft- und Raumfahrt Annietmuttern, selbstsichernd, beiderseitiger, Flansch, mit zylindrischer Aussenkun
4、g, aus hochwarmfestem Stahl, versilbert Klasse : 1 100 MPa (bei Raumtemperatur) I425 OC This “Aerospace Series I Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on green paper for the needs of AECMA-Members. It has b
5、een technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, ph ysically or functionally, without
6、 re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPSI and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. 199
7、7-01 -31 AECMA Gulledelle 94 B-1200 BRUXELLES Mr Arena I I aecma 199 Page 3 prEN 4255 1 Scope This standard specifies the characteristics of self- locking, fixed, two lug anchor nuts, with counterbore, in heat resisting steel, silver plated. Classification : 1 100 MPa / 425 “C 2, 2 Normative referen
8、ces IS0 3223 IS0 5855-2 IS0 5858 IS0 8788 EN 2000 EN 2424 EN 2786 EN 3042 TR 3791 Aerospace-Nuts, anchor, self-locking, fixed, two lug, with counterbore, with MJ threads, coatedor uncoated, classification 1 100 MPa/235 OC, 1 100 MPa/315“Cor 1 100 MPa/425“C - Dimensions Aerospace - MJ threads - Part
9、2 : Limit dimensions for bolts and nuts Aerospace - Self-locking nut with maximum operating temperature less than or equal to 425 “C - Procurement specification Aerospace - Fasteners - Tolerances of form and position for nuts Aerospace series - Quality assurance - EN aerospace products - Approval of
10、 the quality system of manufacturers Aerospace series - Marking of aerospace products 3, Aerospace series - Electrolytic silver plating of fasteners 4, Aerospace series - Quality assurance - EN aerospace products - Qualification Aerospace series - Materials for all metal self-locking nuts and thin w
11、all inserts of temperature classes I425 “C 3, 1) Corresponds to the minimum stress which the nut is able to withstand at ambient temperature, without breaking or cracking when tested with a bolt of a higher strength class. 2) Maximum temperature that the nut is able to withstand, without permanent a
12、lteration to its original charac- teristics, after ambient temperature has been restored. The maximum temperature is conditionned by the dimension 3) Published as AECMA Technical Report at the date of publication of this standard 4) Published as AECMA Prestandard at the date of publication of this s
13、tandard Previous page is blank STD-AECMA PREN 4255-ENGL 1777 1012311 0012178 5T3 W Page 4 prEN 4255 3 Required characteristics 3.1 Configuration - Dimensions - Masses See Figure 1 and Table 1. Dimensions and tolerances are: in conformity with IS0 3223, expressed in millimetres and apply after surfac
14、e treatment. Details of form not stated are at the manufacturers option. The cap shall remain joined (type of attachment at the users discretion) to the nut at the maximum operating temperature. See test conditions in IS0 5858. 3.2 Tolerances of form and position IS0 8788 3.3 Materials TR 3791 3.4 S
15、urface treatment EN 2786, thickness : - on external surfaces: 5 pm to 15 pm ; - on pitch diameter : 5 pm minimum for nuts MJ6 and larger. Nuts MJ5 and smaller shall show complete coverage over complete profile. Remove sharp edges 0,l to 0,4 Y-Y Page 5 prEN 4255 Alternatives : countersunk rivet holes
16、 (when specified by purchaser) may be dimpled or cut countersunk (at manufacturers option). Form out-of-round 1) These values in micrometres apply before surface treatment. They do not apply to threads, punched holes or sheared edges, the surface texture of which will be as achieved by usual manufac
17、turing methods. 2) Tooling marks are permitted in this area. Figure 1 Table 1 Diameter Thread 1) C D E F G H Jz) K L M N3) e) O R S V Mass51 code max rnax min min max rnax max rnax max rnax rnax - ) In accordance with IS0 5855-2. In the self-locking zone the tolerances apply before forming out-of-ro
18、und 2) Measured at sharp corners (chamfered) or point of tangency (radiused) 3) Measured at the rivet hole location 4) Maximum protrusion of the bolt 5) Approximative values (kg/l O00 pieces), given for infomation purposes only. They apply to anchor nuts without cap - - STD-AECMA PREN q255-ENGL 3777
19、 3032313 O032380 353 E Page 6 prEN 4255 Description block 4 Designation Identity block EXAMPLE : Option Plain rivet holes Dimpled or countersunk rivet holes Code - (hyphen) K Rivet hole and cap code (see table 2);1 Diameter code (see Table 1) Plain rivet holes + cap Dimpled or countersunk rivet hole
20、s + cap NOTE : If necessary, the code 19005 shall be placed between the description block and the identity block. Table 2 B A 5 Marking EN 2424, style N. See Figure 1. 6 Technical specification IS0 5858, except for : - Approval of manufacturers : see EN 2000 ; - Qualification of products : see EN 3042.
