1、 - AECMA PRENx3b3 96 3032333 0030472 T43 Edition approved for publication 1996-05-31 AECMA STANDARD NORME AECMA AECMA NORM C5 Chairman Mr Odorico Comments should be sent within six months after the date of publication to AECMA Gulledelle 94 B-1200 BRUXELLES prEN 3683 Edition P 1 May 1996 PUBLISHED B
2、Y THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 6-1 200 BRUXELLES - Tel. (321 2 775 81 10 - Fax. (32) 2 775 81 11 ICs Descriptors ENGLISH VERSION Aerospace series Test methods Titanium alloy wrought products Determination of primary a content Point count method and line in
3、tercept method Srie arospatiale Luft- und Raumfahrt Mthodes dessais Prfverfahren Demi-produits corroys en alliages de titane Dtermination de la teneur en a primaire Mthode par comptage de points et mthode par interception de lignes Kneterzeugnisse aus Titanlegierungen Bestimmung von Primr-a-Anteilen
4、 Punktzhlverfahren und Linienschnittverfahren This “Aerospace Series“ 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 been technically approved by the experts of
5、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, physically or functionally, without re-identification of the standard. After ex
6、amination and signature of the AECMA Standard Checking Centre (NPS) 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. STD=AECMA PREN 3b83-ENGL L99b LOL23LL 00L22b7 b
7、T7 Page 2 prEN 3683 : 1996 Contents list Scope Normative references Definitions Principle Sampling and sample preparation Test methods Expression of results Test report AECMA PRENr3683 96 LOL23LL 0010474 8Lb H Page 3 prEN 3683 : 1996 1 Scope This standard specifies two methods, the point count metho
8、d and the line intercept method, for optical microscope determination of primary a content of titanium alloy wrought products, for aerospace applications. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative refe
9、rences 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 only when incorporated in it by amendment or revision. For undated references the
10、 latest edition of the publication referred to applies. EN 31 14-1 Aerospace series - Microstructure of (a + ) titanium alloy wrought products - Part 1 : General requirements 1) 3 Definitions For the purposes of this standard, the following definitions apply : See EN 31 14-1. 4 Principle Micrographi
11、c examination for determination of the primary a content by : - Counting the number of points of a Specified point grid, enclosed in a particles, point count method (Method A) ; - Determining the lengths of lines of a specified line grid intercepted by a particles, line intercept method (Method B).
12、5 Sampling and sample preparation The test sample shall have a size such that the section to be examined shall not be less than 10 mm in diameter or square. The surface of the section shall be prepared according to EN 31 14-1. 6 Test methods 6.1 Point count method (Method A) Superimpose the specifie
13、d point grid (see example in figure 1) on the section to be examined. Adjust magnification so that each primary a particle does not coincide with more than one point of the grid : Assessment is carried out as follows : - all those points on the grid which are enclosed by a primary c1 particle are co
14、unted ; - a point lying exactly on a phase boundary is counted as 0,5 point ; - the sum N (a) of these points divided by the total number N of the grid points equals the amount of primary a, Np ; - Np corresponds to the volume (Vv) of primary a on the surface area covered by the point grid. 1) In pr
15、eparation at the date of publication of this standard AECMA PREN*3b83 b = 1012311 001Oq75 752 Page 4 prEN 3683 : 1996 See figure 1 for an example of the calculation. Figure 1 : Illustration of the point count method The diamonds represent a particles. The dots represent points of the grid. The cross
16、es represent points enclosed within a particles. Example : Total number of points in the grid N =25 The number of points enclosed by an a particle N (a) = 7 Calculation of the content of a : The statistical error (AV,) is calculated as follows : d Npx (l-Np N AV, = 2 x It is recommended that the cou
17、nt be carried out at several locations within the surface under examination to improve the accuracy of the determination by averaging. AECMA PREN83b83 76 = 1012311 0010476 699 D Page 5 prEN 3683 : 1996 6.2 Line intercept method (Method BI Superimpose the specified line grid (see example in figure 2)
18、 on the section to be examined. Adjust magnification so that each primary a particle in not intersected by more than one grid line in each direction. Assessment is carried out as follows : - the lengths of all portions of the grid lines which lie over an a particle are added to produce the total S (
19、ci) ; - this count shall be carried out in both directions of the grid ; - the value S (a) divided by the total length S of all the grid lines within the surface under examination equals the grid line portion content NL attributable to the primary a content and corresponds to the volume (V,) of prim
20、ary ci on the surface area covered by the line grid. See figure 2 for an example of the calculation Figure 2 : Illustration of the line intercept method The diamonds represent ci particles. The square lines represent the grid. a + b = the length of the grid lines S(u). Example : Total length of all
21、grid lines S = 900rnm The total of all a and b lengths S(a) = 204 mm Calculation of the content of primary CI : - 0,23 204 S 900 - s (u) Page 6 prEN 3683 : 1996 The statistical error (AV,) is calculated as follows : 1 2 AVv=2N/i. s(S(a) +I x - fi where : s(S(a) is the standard deviation of line port
22、ion length distribution; L is the mean value of the line portion length; N is the number of intersected a particles. - It is recommended that the count be carried out at several locations within the surface under examination to improve the accuracy of the determination by averaging. 7 Expression of
23、results For each method, the individual or average values of primary c content shall be given with the corresponding calculated statistical error. 8 Test report The test report shall refer to this standard and shall include : - complete identification of the tested material, including the manufactur
24、ers name, designation and batch number ; - location of test sample ; - method of test sample preparation ; - all relevant test sample dimensions ; - date of test and traceability to individuals performing the test work ; - test method used : point count method (Method A) or line intercept method (Method B) ; - equipment used : type of grid ; - number of locations sampled ; - test results (see 7) ; - any factor which may have affected the results and any deviation from the test method.
