1、STD-AECMA PREN 4050-2-ENGL L77b LOL23LL OOL2LOb 307 AECMA STANDARD NORME AECMA AECMA NORM prEN 4050-2 Edition P 1 January 1996 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - B-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 bars, plates, forging stock and forgings Part 2 : Performance of test Srie arospatiale Luft- und Raumfahrt Mthode dessai applicable Prfverfahren fr aux matriaux mtalliques metallische Werkstoffe Contrle par ul
3、trasons de barres, plaques, demi-produit pour forgeage et pices forges Partie 2 : Ralisation de lessai Ultraschallprfung von Stangen, Platten, Schmiedevormaterial und Schmiedestcken Teil 2 : Durchfhrung der Prfung This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECM
4、A (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 Member countries. Subsequent to the publication of this Prestandard, the
5、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 (NPS) and formal agreement of the Official Services of the Member coun
6、tries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. Nata - Extra copies can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau - 921 38 ISSY-LEC-MOULINEAUX CEDEX I Comments should be sent within six months af
7、ter 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 aecma 1996 STD-AECMA PREN 4050-2-ENGL 377b = 3032333 0032307 2Li3 = Page 2 prEN 4050-2 : 1996 Contents list Page 1 2 3 4 5 6 7 8 9 10 Scope 3 Normative referen
8、ces . 3 General 3 Performance characteristics of the inspection system . 4 Measurement of material Characteristics . 5 Flaw recognition level 5 Setting-up procedure . 5 Monitored systems 7 Equipment requirements . 8 Periodic control checks 8 Page 3 prEN 4050-2 : 1996 1 Scope This standard specifies
9、the method of performing ultrasonic testing. The general requirements are given in EN 4050-1. 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 th
10、e 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 latest edition of the publication referred to applies. EN 40
11、50-1 Aerospace series - Test method for metallic materials - Ultrasonic inspection of bars, plates, forging stock and forgings - Part 1 : General requirements 1) EN 4050-4 Aerospace series - Test method for metallic materials - Ultrasonic inspection of bars, plates, forging stock and forgings - Part
12、 4 : Acceptance criteria 1) 3 General 3.1 Implementation Implementation shall be as required by the relevant technique, inspection schedule or order. 3.2 Test procedures The equipment to be used, its performance, the scanning plan and the acceptance standard shall be as defined in the relevant test
13、procedure, inspection schedule or order for each item. 3.3 Calibration of the flaw detector time base The time base shall be calibrated and care shall be taken to ensure that interface and target echoes can be readily identified. 3.4 Scanning speed and pitch To ensure efficient inspection of the ent
14、ire volume of the material, the scanning speed and pitch shall be established taking into account the test beam diameter, the acceptance standard and the pulse repetition frequency. Account shall also be taken of whether a manual or automatic system of flaw detection is used. 3.5 Scanning index The
15、scanning index shall be such that the reference reflector always produces at least two indications on two successive pulses. The two signals shall not be more than 6 dB lower than the maximum indication of the reference reflector measured in the static conditions. 1 ) Published as AECMA Prestandard
16、at the date of publication of this standard Page 4 prEN 4050-2 : 1996 3.6 Wave modes There are different ultrasonic wave modes, namely - longitudinal ; - shear; - surface ; - lamb waves. The wave mode shall be as specified in the relevant technique or inspection schedule. 3.7 Sensitivity corrections
17、 Corrections for distance/amplitude effects, attenuation, shape effects and specified acceptance standard shall be made to attain the desired level of sensitivity in the part being examined. 3.8 The inspection system shall generate and contain sufficient information to enable flaw size and position
18、to be derived with respect to the scanning sequence and reference data from the equipment. Flaw size and position recording 4 Performance characteristics of the inspection system 4. I Requirements In order to meet the specific requirements for each test item of the procedural document for each part
19、number and for optimum and reproducible inspection, it is essential that the characteristics and performance data of all the equipment are measured and recorded. This is defined in the three following sections : - the probe and flaw detector that are used in establishing the working sensitivity and
20、for evaluating flaws ; - periodic control checks carried out on the facility ; - specific operating and control instructions unique to each facility ; this latter point is particularly directed to automatic and semi-automatic facilities. Table 1 lists the requirements for identification and performa
21、nce measurement of the equipment which is to be used in establishing the working sensitivity, inspecting and evaluating flaws. As there may be differences between equipment performances, when used on manual or automatic modes, the corresponding calibration shall be carried out. The methods of derivi
22、ng these basic data are detailed in the following paragraphs. 4.2 Ultrasonic test set The ultrasonic test set used shall operate in the pulse-echo mode and, if required, shall also be capable of operating in the through-transmission mode. Gain calibrated in steps of 1 dB max. shall be used (steps of
23、 2 dB may be agreed). When required a means of reducing the back-wall echo shall be provided, but the possibility of flaw detection shall remain unimpaired. Equipment featuring distance amplitude correction shall be used. Equipment shall be calibrated. STD-AECMA PREN 4050-2-ENGL 1976 LOL23LL OUL2LLO
24、 838 H Page 5 prEN 4050-2 : 1996 5 Measurement of material characteristics 5.1 Attenuation The attenuation in the part under test shall be measured for application to working sensitivity and flaw evaluation. The attenuation factor shall preferably be measured by comparison with a reference test bloc
25、k, the acoustic impedance and geometry of which are similar to that of the product to be inspected and the attenuation of which has been previously evaluated using the same probe/flaw detector combination. This measurement shall be made using the same operating conditions and probe/flaw detector com
26、bination, limited to sections with parallel faces, diametrically opposing faces, and for grain flow correction. Sections of material with non parallel faces can be assessed for material attenuation based on figures obtained from a nearby parallel sided section. 5.2 Structure noise (grass) Structure
27、noise (grass) limits the ability to detect flaws. Grass may therefore need to be measured in order to determine to what level a part can be inspected. The flaws to be detected shall rise 6 dB or more above the structure noise. The measurement of structure noise shall be carried out at the same equip
28、ment settings and by that method used for inspection. 6 Flaw recognition level The flaw echo amplitude as seen on the flaw detector screen during inspection may have been diminished by the effects of attenuation, depth, flaw tilt, scanning pitch and pulse repetition frequency. To ensure that rejecta
29、ble flaws are not ignored because of their diminished response, it is necessary to establish a monitor threshold level above which all indications shall be evaluated. This shall be carried out in accordance with the relevant technique, or inspection schedule. NOTE : When using the manual contact tec
30、hnique an additional gain of + 6 dB may be added to correct this diminution. 7 Setting-up procedure 7.1 Choice of probe The choice of probe for inspection will depend upon a number of factors governed largely by the component to be inspected and the acceptance standard to be applied. 7.2 Choice of i
31、nspection frequency The inspection frequency chosen shall be such as to ensure that a signal-to-noise ratio of 6 dB or greater shall be attained in accordance with the flaw detection capability. STD-AECMA PREN 4050-2-ENGL Lb W LOL23LL 0012LLL 774 .I Page 6 prEN 4050-2 : 1996 7.3 Inspection water gap
32、 shall be defined and maintained according to the relevant technique test procedure taking into account the need to optimize either near surface resolution or sensitivity, or to obtain the best compromise of the two. Where of significant magnitude, water attenuation effects shall be taken into accou
33、nt, as agreed between manufacturer and purchaser. The distance (L) between transducer and part is related to the thickness (t) of the given part, velocity of sound in water (v,) and velocity of sound in the material of the part (vpan) and is given in L/t 2 v, / vpart Choice of water gap (immersion t
34、echnique) 7.4 The coupling conditions for the material under test and the standard test block shall be the same. For inspection by the contact method clean tap water, oil, glycerine or cellulose gum may be used as the couplant. The acoustic impedance, viscosity and surface wetting of the couplant sh
35、all maintain good ultrasonic energy transmission into the test material and low attenuation of the sound beam. When used, the type and thickness of the protecting membranes of the probes shall allow adequate sensitivity. Type of coupling (contact technique) 7.5 Basic reference sensitivity The basic
36、reference sensitivity is used to establish the working sensitivity by the addition of the material standard, of those characteristics attributable to the part, that is : transmissivity at interface and attenuation. This specification contains two methods of establishing the basic reference sensitivi
37、ty, working sensitivity and the evaluation of flaws. These represent the methods currently in use. It shall be recognized that these methods are not necessarily mutually interchangeable or comparable. 7.5.1 The method as described applies to plane unfocused and narrow frequency band probes only. Dis
38、tance gain size (DGS) method 7.5.1 .I Reference sensitivity The DGS method is implemented using the general diagram (figure 1). Sensitivity is determined from the back echo. In the event where it is not possible to obtain a back echo on the part, the use of a block to obtain a back echo is permitted
39、, if the material of the block has similar characteristics to those of the product to be inspected. 7.5.1.2 Working sensitivity The working sensitivity is achieved by adding the loss due to material attenuation to the reference sensitivity, Where the acceptance standard differs from the 1.2 mm flat
40、bottom hole standard, a corresponding adjustment in gain is required. 7.5.1.3 Flaw evaluation Flaw evaluation is carried out using the DGS diagram as illustrated in figure 2. The flaw shall be positioned between 1.5 N and 3 N distance. Additional corrections shall be made due to water attenuation. T
41、he amplitude of the flaw shall be maximized by probe manipulation and compared with the amplitude of the reference plate back wall echo using the same derived water distance. Local attenuation corrections are made to this figure : knowing the effective probe diameter, the equivalent flat bottom hole
42、 diameter is calculated from the S size factor of the diagram. Detailed operating instructions for flaw evaluating by the DGS method shall be defined in the relevant inspection operation sheet. NOTE : If this method is applied on curved surfaces, additional correction factors will need to be taken i
43、nto account. STD-AECMA PREN 4050-2-ENGL 177b D LOL23LL 0022112 b M Page 7 prEN 4050-2 : 1996 7.5.2 Flat bottom holes (FBH) 7.5.2.1 Reference sensitivity The basic reference sensitivity is derived from one of a series of drilled targets in an appropriate material, either FBH and shall take into accou
44、nt material under test and material acceptance standard. These targets shall be referenced when appropriate to a master standard and shall have correction factors, due to variation of their geometry. Using the inspection water gap (immersion technique), a distance/amplitude curve is plotted from the
45、se targets and suitably corrected. The relevant technique sheet shall define the method by which the hole used to establish the working sensitivity has to be selected. The echo from this hole shall be brought to the reference height on the flaw detector screen graticule. 7.5.2.2 Working sensitivity
46、The working sensitivity is derived from the basic reference sensitivity, taking into account attenuation, thickness and shape of the part under test and material acceptance standard. According to local variations of these parameters, it may be necessary to use several working sensitivities on the sa
47、me part. 7.5.2.3 Flaw evaluation Maintaining the inspection water gap (immersion technique), the flaw amplitude shall be maximized by probe manipulation. A comparison shall be made between the maximized flaw amplitude and the amplitude of either : a) the point equivalent in depth taken from the FBH
48、distance amplitude curve. b) a hole in the actual test block having the same depth as the flaw within the following tolerances : - up to 6 mm depth : f 1,5 mm - above 6 mm to 10 mm depth : 4 2mm - above 10 mm to 50 mm depth : 4 5mm - above 50 mm to 70 mm depth : 4 10mm - above 70 mm to 100 mm depth
49、: f 15mm - above 100 mm to 200 mm depth : f 25mm Where hole and flaw depth do not correspond, a correcting factor is required, (e.g. : linear interpolation) The result of this comparison shall be corrected for the alloy under test and local attenuation. If the contact technique is used, the procedure shall be analogous. 8 Monitored systems Monitored systems are to be preferred in order to ensure more reliable flaw detection. 8.1 Description When these systems are used, it shall be demonstrated that these aids are effective in achieving required process capa
