1、STD-AECMA PREN 3718-ENGL Ll7b LOI12311 0012233 2Lb m AECMA STANDARD NORME AECMA AECMA NORM prEN 371 8 Edition P 1 January 1996 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 8-1200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : Descriptors : EN
2、GLISH VERSION Aerospace series Test method for metallic materials Ultrasonic inspection of tubes Srie arospatiale Mthode dessai applicable aux matriaux mtalliques Contrle par ultrasons des tubes Luft- und Raumfahrt Prfverfahren fr metallische Werkstoffe Ultraschallprfung von Rohren This “Aerospace S
3、eries“ 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 the concerned Technical Committee following comment by the Memb
4、er 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 examination and signature of the AECMA Standard Checking Centre I
5、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. Nota - Extra copies can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau - 921 38 ISS
6、Y-LES-MOULINEAUX CEDEX I Comments should be sent within six months after the date of publication to I Edition approved for publication 1 996-0 1 -3 1 AECMA Gulledelle 94 B-1200 BRUXELLES C5 Chairman Mr Odorico 0 aecma 1996 Page 2 prEN 371 8 : 1996 Contents list Page 1 2 3 4 5 6 7 8 9 10 11 Scope 3 N
7、ormative references . 3 Definitions 3 Short description of the procedure . 3 Equipment requirements . 3 Preparation for inspection . 8 Inspection procedure 8 Evaluation 9 Written instruction . 1 O Qualification and approval of personnel 1 O Inspection and test report . 1 O STD*AECflA PREN 37LB-ENGL
8、199b M 201Z31L 0012235 O79 9 Page 3 prEN 3718 : 1996 1 Scope This standard specifies the requirements for ultrasonic inspection of tubes in metallic materials with an external diameter 2 5 mm. For other cases, the use of this standard is by agreement between the manufacturer and the purc hacer. The
9、purpose of the ultrasonic inspection is the detection of defects within the wall thickness and at the outer and inner surfaces of the tube. The method will detect two dimensional defects in the longitudinal and circumferential directions perpendicular to the tube wall. Where inspection for other typ
10、es of defects is required, this requirements shall be stated on the order. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are
11、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 latest edition of the publication referred to applies. IS0 7963 EN 2078 EN 4050
12、-1 EN 4179 Welds in steel; calibration block no 2 for ultrasonic examination of welds Aerospace series - Metallic materials - Manufacturing schedule - Inspection schedule - Inspection and test report - Description and rules for use Aerospace series - Test method for metallic materials - Ultrasonic i
13、nspection of bars, plates forging stock and forgings - Part : 1 General requirements 1) Aerospace series - Qualification and approval of personnel for non-destructive testing 1) 3 Definitions See EN 4050-1 4 The inspection shall be carried out using ultrasonic test equipment, which emits ultrasonic
14、signals passing through a liquid coupling medium obliquely into the tube under test and which receives and evaluates the reflected (or transmitted) signals. The tubes shall be inspected automatically and completely .e. the relative movement of probe and tube under test shall be accomplished with the
15、 aid of a manipulator. The corresponding signal amplitudes from the ultrasonic test equipment shall be plotted as a function of the location, e.g. amplitude scans or C-scans. Short description of the procedure - - 5 Equipment requirements 5.1 Calibration blocks Calibration blocks as per IS0 7963 or
16、equivalent standards shall be used to check the proper function and characteristics of the ultrasonic test unit and probes. The method of checking the equipment and requirements concerning the calibration blocks shall be agreed between the manufacturer and the purchaser. 1) Published as AECMA Presta
17、ndard at the date of publication of this standard STD*AECMA PREN 37LB-ENGL 177b W LO123LL 00L223b TZC Page 4 prEN 371 8 : 1996 5.2 Reference specimens A reference specimen shall be fabricated from a tube consisting of the same material, having the same nominal diameter, wall thickness, surface condi
18、tion and heat treatment condition as the tubes to be inspected. The selected length of the reference specimen shall be such that it can be tested in the test system described below. The reference specimen shall not have any defects or other irregularities that can produce indications or interfere wi
19、th the detection of the reference notches. Four reference notches of the same dimensions (depth, width, length) as shown in figure 1 shall be introduced in each tube. The depth, width and length of the notches are defined in table 1 and subdivided into classes. A-A B-B c-c 0-0 - b - ,+ t = Depth R2=
20、 Rl+t dl7 b = Width 1 = Length di = Internal diameter d, = External diameter P 2 20mm A-A and B-B : Longitudinal defects C-C and 0-0 : Circumferential defects R2= - 2 r2 = rl + t r2 = - di 2 Figure 1 : Reference specimen with four notches in longitudinal and circumferential direction on the inner an
21、d outer surface of the tube wall STD-AECMA PREN 373B-ENGL L77b 30L2333 0032237 Yb3 Class 5 4 3 2 1 Page 5 prEN 3718 : 1996 Depth Length Width 0,05 13 0,lO 0,05 3,O 0,lO 0,08 3,O 0,lO 0,lO 3,O 0,lO 5 % of a *) 6,O 0,lO Table 1 : Reference notch dimensions The reference notches shall be rectangular fo
22、r notches in the longitudinal direction and shall have the shape of a ring segment in the circumferential direction and edge radii IO,13 mm. The depth of the notch shall correspond to a mean value, measured from the tube surface to the respective penetration depth of the notch. Notch dimensions shal
23、i comply with the values specified in table 1 to within _+ 15 %. The notch depth shall be measured from the circular surface to the deepest penetration of the notch. Measurements may be made by replication or by a destructive method on a duplicate notch which has identical ultrasonic response (ampli
24、tude within 90 % to 110 % of the reference notch amplitude). In order to have access to notches lying inside the reference specimen, a window may be cut into the opposite tube wall to provide access to the notch. The window shall not be so large as to interfere with the ultrasonic responses from the
25、 notch. Each reference specimen shall be identified. The serial number and EN 3718 shall be permanently marked on the reference specimen and the following information shall either be marked on the specimen or maintained in a log book : alloy, heat treatment condition, diameter, wall thickness, size
26、and location of reference notches. 5.3 Ultrasonic test equipment The ultrasonic test equipment shall be of the pulse echo type with appropriate signal outputs for registration of the measuring values. 5.4 Probes and probe arrangement In view of the geometry of the defects anticipated, the use of sph
27、erical or cylindrical focused probes as determined by the specified notch dimensions is recommended. For the ultrasonic echo inspection to detect defects running primarily in the longitudinal or circumferential direction of the tube, identical probes shall be used to achieve oblique incidence on bot
28、h sides of the tube. The probes shall be sufficiently far apart to ensure that they will not influence one another. It is also possible to use just one probe on one side, although it is then necessary to inspect from the other side in a subsequent run. For example, the inspection of steel tube may b
29、e carried out by using 45O transverse waves. In this case the angle of incidence in water is approximatively 17O for detection of defects in longitudinal tube direction (see figure 2), and approximatively 19O for detection of defects in circumferential tube direction (see figure 3). STD-AECMA PREN 3
30、718-ENGL 377b D 1012313 0032238 BT8 Page 6 prEN 371 8 : 1996 II- Probe 2 =-U Figure 2 : Oblique incidence on both sides to detect defects in longitudinal direction of the tube cc = 17O Probe 1 c b Probe 2 Figure 3 : Oblique incidence on both sides to detect defects in circumferential direction of th
31、e tube = 19O 5.5 Coupling A liquid couplant such as water, oil or glycerine shall be used for conduction of the ultrasonic longitudinal waves between the probes and the tube wall. Wetting or anti-corrosion agents may be added to the couplant, provided that the surface conditions of the tube is not i
32、mpaired. Bubbles are not allowed in order to avoid any disturbance of the transmission of sound. Sound coupling may be achieved by immersion of the probe and tube. Coupling is also possible by having a local stream of fluid between the two, whilst ensuring that the flow is not turbulent (squirter te
33、chnique). STDmAECMA PREN 37LB-ENGL 199b LOL23LL 0012239 73Li = Page 7 prEN 3718 : 1996 5.6 Manipulator Using a manipulator, the helix and rotational speed shall be such that two return signals are recorded from the reference notch. The two signals shall not be more than 6 dB lower than the maximum i
34、ndication of the reference notch. See figure 4. Figure 4 : Test trace in the case of helical movement 5.7 Evaluation and recording unit The ultrasonic signals of interest received by the ultrasonic apparatus, shall be gated out and their amplitudes registered by a recorder plotting them as a functio
35、n of the respective location on the tube. Evaluation and recording is also possible by using a computer and a plotter for producing amplitude scans or C-scans. 5.8 The inspection equipment and the procedure for the respective type of defect primarily to be found (see description of reference specime
36、n in clause 5.2) shall fulfil the following requirements with regard to detection sensitivity : - indication of the corresponding notch of the reference specimen for the respective tube type with a signal-to-noise ratio of at least 12 dB (with reference to faultless condition). In the case of extern
37、al defects, indications shall be based on a one-skip-distance arrangement; - complete separation time-wise of the evaluation signal from any other signal (e.g. surface signal); - demonstration of reproducibility by means of plots. Detection sensitivity of the equipment One procedure is normally requ
38、ired for each main type of defect, however the following simplifications are possible : - if the signal indications of the reference notches in longitudinal (or circumferential) tube direction fulfil the above-mentioned criteria on the inside and outside and do not differ by more than 10 %, the tube
39、s may be simultaneously inspected for internal and external defects in longitudinal (and circumferential) direction of the tube. In this case, the entire time range of the signal from the inner and outer notch shall be gated in one or two channels (see figure 5) and evaluated on the basis of the one
40、 channel threshold level. STD*AECMA PREN 37LB-ENGL L77b LOL23LL OOLZZii q5b W Page 8 prEN 371 8 : 1996 a) I I- One channel b) 1 Channel 1 2- 1- Channel 2 Figure 5 : Gating of signals Si (inner notch) and Sa (outer notch) 6 Preparation for inspection 6.1 Check of tubing surface The inner and outer su
41、rfaces of the tubes shall be clean and free from damage, dirt, grease, paint and any other surface contamination which might affect the interpretation of the inspection results. Neither the metal nor its final surface condition shall be impaired by the surface cleaning and pretreatment procedures ca
42、rried out prior to the ultrasonic inspection. The inner surface shall be dry to avoid false indications from fluid droplets. Tubes shall be plugged. The mean depth of surface roughness Ra shall not exceed 2,5 pm. 6.2 Instrument calibration Using the reference specimen as per clause 5.2, the test equ
43、ipment shall be set to a certain indication value with reference to the respective reference notches) subsequent to completion of the time adjustment (path adjustment). Adjustment shall be carried out under dynamic conditions ; one plot of a reference specimen shall be kept to document the correct a
44、djustment. The helical scan pitch and rotational speed shall be such that the respective reference notch always lower than the maximum indication of the reference notch. For tubes with a wall thickness 1,5 mm the focus shall be in the tube wall. Water path shall be adjusted so that the focal spot of
45、 the source beam lies at the middle of the wall thickness of the tube during calibration and inspection. The adjustment of the overall system prior to and after tube inspection shall be checked at intervals as agreed between manufacturer and purchaser, using the corresponding reference specimen. Dev
46、iations on the plots shall not exceed 10 %; if they do the tube inspection, carried out in this workshift, shall be repeated. - produces at least two indications on two adjacent traces. The two signals shall not be more than 6 dB - 7 Inspection procedure The tubes shall be inspected under identical
47、conditions to those applied during instrument calibration. Identical conditions shall include all instrument settings, mechanical motions, probe arrangement and position relative to the tube, liquid coupling and any other factors that affect the performance of the inspection. The inspection shall be
48、 carried out in one direction, either with oblique incidence on both sides as illustrated in figures 2 and 3, or with oblique incidence from one side with additional run with oblique incidence from the opposite side. Figure 6 shows an example of a complete tube inspection in one run : the simplified
49、 procedure of inspecting for internal and external defects simultaneously as outlined in 5.8. STD*AECMA PREN 3718-ENGL 1996 LIIL2311 OOL2241 372 W Probe 1 I - Probe2 - Probe3 - Probe 4 + r Channel 1 Channel 2 Channel 3 Channel 4 T Page 9 prEN 3718 : 1996 T Ultrasonic Evaluation equipment und recording unit Figure 6 : Example of a tube inspection : Inspection in one run simultaneously for internal and external defects in longitudinal and circumferential tube directions, rigid mechanical coupling of the four probes to one another. 8 Evaluation Signal indications 2 50 % (6 d
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