1、STD-AECMA PREN 2751-ENGL 1777 = LO123LL 0034077 357 = Edition approved for publication AECMA STANDARD NORME AECMA AECMA NORM C5 Chairman Comments should be sent within six months after the date of publication to prEN 2951 Edition P 1 November 1997 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE I
2、NDUSTRIES (AECMA) Gulledelle 94 - 8-1200 BRUXELLES - Tel. (+32) 2 775 81 10 - Fax. (+32) 2 775 81 11 ICs: Descriptors: ENGLISH VERSION Aerospace series Metallic materials Test method Micrographic determination of content of non-metallic inclusions Srie arospatiale Matriaux mtalliques Mthode dessai D
3、termination par micrographie de la distribution dinclusions non-mtalliques Luft- und Raumfahrt Metallische Werkstoffe Prfverfahren Mikrographische Bestimmung von nichtmetallischen Einschlssen This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (The European Associ
4、ation of Aerospace Industries). 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 following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shal
5、l 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 Member countries it will be submi
6、tted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. 1997-1 1-28 AECMA Gulledelle 94 B-1200 BRUXELLES Mr Odorico aecrna 1997 Contents list O Introduction 1 Scope 2 Normative references 3 Definition 4 Health and safety 5 Test method 6 Classification of de
7、fects 7 Acceptance criteria Annex A (normative) - Acceptance criteria - Categories Annex B (informative) - Acceptance criteria - Examples of the use of combined field ratings - Page 3 prEN 2951 : 1997 STD-AECMA PREN 2951-ENGL 1777 m 3012333 0034077 323 = O Introduction This standard is part of the s
8、eries of EN metallic material standards for aerospace applications. The general organization of this series is described in EN 4258. i Scope This standard specifies the general requirements for the micrographic determination of content of non- metallic inclusions of metallic materials for aerospace
9、applications. It also gives tables of standard acceptance criteria for particular steel types. It shall be applied when referred to in the EN technical specification or material standard unless otherwise specified on the drawing, order or inspection schedule. This standard is mainly applicable to st
10、eel but may be used on other metallic materials. This standard is not normally applicable to austenitic corrosion resisting steel, other than precipitation hardening, or to free-machining steel unless invoked in the material standards. 2 Normative references This European Standard incorporates by da
11、ted or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard
12、only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 4258 Aerospace series - Metallic materials - General organization of standardization - Links between types of EN standards and their use 1) EN 4259 Aerospace se
13、ries - Metallic materials - Definition of general terms 2) ASTM E45-95a Standard Test Methods for Determining the Inclusion Content of Steel 3) 3 Definitions For the purposes of this standard, the following definifions apply: See EN 4259. 4 Health and safety Resources, test pieces, test samples, tes
14、t materials, test equipment and test procedures shall comply with the current health and safety regulationsllaws of the countries where the test is to be carried out. Where materials and/or reagents which may be hazardous to health are specified, appropriate precautions in conformity with local regu
15、lations and/or laws shall be taken. 1) Published as AECMA Prestandard at the date of publication of this standard 2) In preparation at the date of publication of this standard 3) This standard is published by : American Society for Testing and Materials (ASTM), 100 Barr Harbor Dr, West Conshohocken,
16、 PA 19428-2959 - United States STD*AECflA PREN 275L-ENGL 1997 W LOL23LL OOL4LOO 773 W Page 4 prEN 2951 : 1997 Remelted (Vacuum and/or electroslag) 5 Test method D Microscopical method A or method D of ASTM E45-95a is used. A B C Inclusion types The method used Sulphides Aluminates Silicates depends
17、on the melting route of the material and shall be in accordance with table 1. Table 1 Corrosion resisting martensitic Corrosion resisting precipitation hardening I Melting route I Method I 2 2 I Air melted I A I Carbon and low alloy Non corrosion resisting martensitic high alloy Corrosion resisting
18、martensitic Electroslag remelt 3 4 4 Sampling, test specimen geometry and preparation of specimens shall be according to ASTM E45-95a. 6 Classification of defects See table 2. Table 2 I D I Globular oxides I Each inclusion type is classified in two groups of picture series based on the thickness of
19、the inclusions: - thin, - heavy. 7 Acceptance criteria 7.1 Steels Unless otherwise specified in the material standard or order the standard acceptance criteria according table 3 and annex A shall be used. Table 3 7.2 Melting route Steel types I Category I Air melted I Carbon and low alloy I 1 I I No
20、n corrosion resistina martensitic hiah allov I 1 I Single vacuum remelt I All T3 1 Double vacuum remelt I All I 5 I I Corrosion resisting precipitation hardening I 4 I Other metallic materials The acceptance criteria shall be defined in the material standard or order. Annex A (normative) Acceptance
21、criteria - Categories Table A.l Worst field severity per specimen Average of all results per cast tested ASTM E45-95a: Method A Plate I-r A B C D Thin Heavy Thin Heavy Thin Heavy Thin Heavy 23 2 3* 2,5 2,5 2 2 2 2 1,5 2,5 2 2 1.5 1,5 1.5 Worst field severity per specimen Averaae of all results Der c
22、ast tested I Category 3 I ASTM E45-95a: Method A Plate I-r A B C D Thin Heavy Thin Heavy Thin Heavy Thin Heavy 215 2 3,5 3 2,5 2 2 2 2 1.5 3 2.5 2 1.5 1.5 1.5 ASTM E45-95a: Method D Plate I-r A I B I C I D Worst field severity per specimen Worst field frequency (maximum) I Thin I Heavy I Thin I Heav
23、y I Thin I Heavy I Thin I Heavv I 2 1 1,5 1 13 1 1,s 1 1 3 1 * 1 *+ 1 * 1 8 1 * 1 * 1 Total rateable field frequency * (maximum) 1) 1 I Category 4 I (maximum) 1) erity any combination of A, B and C type * Not more than 8 rateable fields with any combination of A, B and C type thin inclusions. For ex
24、ample of use see informative annex B. A rateable field is defined as one which has a type A, B, C or D thin or heavy inclusion rating of at least 1 in accordance with the dimensional limitations specified in Method D of ASTM E45-95a. 1 I STD.AECMA PREN 2951-ENGL 1997 D LOL23Ll ODLLi282 79T Page 6 pr
25、EN 2951 : 1997 Annex B (informative) Acceptance criteria - Examples of the use of combined field ratings The following examples are intended to clarify note * * and * of annex A table A.1. Example 1 Assessing a sample in accordance with the acceptance criteria of category 4: If a sample contains thi
26、n inclusions with one field with a worst severity level of 2 for type A, one field with a worst severity level of 1,5 for type B and one field with a worst severity level of 1,5 for type C, the result complies with note *. To also comply with note * only 5 more fields containing rateable inclusions
27、with combinations A, B and C type inclusions would be allowed. Example 2 Similarly, assessing a further sample in accordance with the acceptance criteria of category 4: If a sample contains thin inclusions with two fields with a worst severity level of 2 for type A, no fields with a worst severity level of 1,5 for type B and no fields with a worst severity level of 1,5 for type C, the result complies with note *. To also comply with note *, 6 other fields containing rateable inclusions with combinations of A, B and C type would be allowed.
