1、Designation: E428 08 (Reapproved 2013)Standard Practice forFabrication and Control of Metal, Other than Aluminum,Reference Blocks Used in Ultrasonic Testing1This standard is issued under the fixed designation E428; the number immediately following the designation indicates the year oforiginal adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This specification has been approved for use by agencies of the Department of Defense.
3、1. Scope1.1 This practice covers a procedure for fabrication andcontrol of metal alloy reference blocks used in ultrasonicexamination that have a flat-surface sound entry, are cylindricalin shape, and contain flat-bottom holes (FBH) which may beused for checking the performance of ultrasonic examina
4、tioninstrumentation and search units and for standardization andcontrol of ultrasonic examination of metal alloy products. Thereference blocks described are suitable for use with either thedirect-contact method or immersion pulse-echo ultrasonicmethods.NOTE 1Use of flat-surface reference blocks may
5、not be suitable forcylindrical materials (3)2.1.2 While this procedure is basically designed for thefabrication and control of carbon and alloy steel blocks to beused in conjunction with the examination of these materials,the fabrication and control procedures may also be suitable forthe preparation
6、 of blocks for other types of materials such asnickel-base alloys, certain types of aluminum alloys, and soforth. Additional procedures and controls may be requiredwhen fabricating reference blocks from other than carbon oralloy steel material. This practice shall in no way preclude thespecification
7、 or addition of any supplemented requirements asdeemed necessary for the specific application. This practice,however, must not be confused with, nor does it supersedePractice E127, specifically governing the fabrication andevaluation of 7075-T6 aluminum alloy ultrasonic standardreference blocks.NOTE
8、 2Practice E127 and Guide E1158 also describe procedures forselecting material, fabricating blocks, and checking response. Unlike thispractice, Practice E127 has requirements for evaluation relative to aspecified standard target.1.3 The values stated in inch-pound units are to be regardedas standard
9、. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standa
10、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E127 Practice for Fabricating and Checking Aluminum Al-loy Ultrasonic Standard Reference BlocksE1158 Guide for Material Selectio
11、n and Fabrication ofReference Blocks for the Pulsed Longitudinal Wave Ul-trasonic Testing of Metal and Metal Alloy ProductionMaterialE1316 Terminology for Nondestructive Examinations3. Terminology3.1 DefinitionsFor definitions of terms used in thispractice, see Terminology E1316.4. Summary of Practi
12、ce4.1 This practice details a basic fabrication and controlprocedure and defines the minimum requirements to be met inmatching carbon and alloy steel reference blocks with thematerial to be examined. Additional supplemental require-ments may be needed when using this practice to fabricatereference b
13、locks from other types of materials or with largerdiameter holes. The physical characteristics of the hole may beestablished by evaluating plastic replicas. It must be recog-nized however that there are limitations on the size hole thatmay be replicated and evaluated.1This practice is under the juri
14、sdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.06 onUltrasonic Method.Current edition approved June 1, 2013. Published June 2013. Originallyapproved in 1971. Last previous edition approved in 2008 as E428 - 08. DOI:10.1520/E0428-08R13.2
15、The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Documen
16、t Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 Reference blocks fabricated in accordance with thispractice will exhibit specific area-amplitude and distance-amplitude relat
17、ionships only with an immersion test at 5 MHzusing the search unit, test instrument and test parametersdescribed in this practice. Comparison test at other frequenciesor with uncalibrated instruments will not necessarily give thesame relationships shown in this practice. See Reference (1)for area-am
18、plitude limitations at other frequencies and trans-ducer diameters. Also see Reference (2) for cautions regardinguse of standard blocks for test standardizations.6. Material Selection6.1 The material to be used for reference blocks should besimilar in its acoustic attenuation to the material which i
19、s to beexamined. The grain size, heat treat condition, physical andchemical composition, surface finish, and manufacturing pro-cedure (rolling, forging, and so forth) are variables to beconsidered in matching acoustic responses.6.1.1 The general evaluation procedure shall be to introducea longitudin
20、al pulse-echo beam into either side of the block onthe axis to be used for determining metal-path distance. Animmersion examination method using clean water as a couplantor, a contact method using appropriate couplant (oil, glycerin,and so forth) is satisfactory. The examination instruments,frequenc
21、y, and search unit used in the evaluation of the rawmaterial intended for the fabrication of the reference blocksshall be comparable to that used in the examination of theproduction material.6.1.2 The material used for reference blocks shall be 100 %scanned while the examination system is adjusted t
22、o display,whenever possible, an acoustic noise level from the material of20 % of full-scale deflection (FSD). In cases of materials thatare acoustically transparent to the extent that this requirementcannot be satisfied, a readable acoustic noise level shall bedisplayed. The acoustic noise level fro
23、m the material is not tobe confused with inherent electrical instrument noise oftenobserved when the system sensitivity is adjusted to its maxi-mum level range.6.1.3 The material used for reference blocks shall be free ofdiscrete ultrasonic discontinuity indications greater than twicethe amplitude o
24、f the noise level displayed in accordance withthe requirements of 6.1.2.6.1.4 Attenuation shall be checked by comparing multiplereflections from the back surface of the test block material withthat of the material to be examined. With the amplitude fromthe first back reflection adjusted to 90 % of F
25、SD, the sum of theamplitude of the first three back reflections from both samplesshall compare within 625 % or as required by the application.On samples that are to have FBHs smaller than364 in. (1.2 mm)in diameter, the decay patterns shall compare within 610 % oras required by the application.6.1.5
26、 Lowering the examination frequency tends to mini-mize discernible differences in response. At 1.0 MHz, a largegroup of materials may be acoustically penetrable with rela-tively similar results and may satisfy the requirements of 6.1.4.At frequencies such as 5.0 MHz and higher, microstructurechanges
27、 usually yield readily discernible differences in acous-tic response and restrict the applicability of reference blocks.7. Fabrication Procedure7.1 Unless otherwise specified, select the blocks to be madefrom those listed in Table 1. Block sets conforming tocustomary commercial practice are grouped
28、as follows:7.1.1 Distance-Amplitude Response (D/A),7.1.2 Area-Amplitude Response (A/A), and7.1.3 Basic (selected from D/A and A/A groups).7.2 All blocks are to be fabricated in accordance with Fig. 1.Dimension “A” (metal travel) and Dimension “D” (FBHdiameter) are given in Table 1; Dimension “E” (bl
29、ock length)is derived. The following machining sequence is recom-mended:NOTE 3This practice may be used to produce blocks with flat-bottomholes of a larger diameter than described. Utilization of larger flat-bottomholes shall be by agreement of the using parties.7.2.1 Machine all blocks to a uniform
30、 32 rms finish and tothe required dimensional tolerances.7.2.2 Drill the test hole to the nominal34-in. (19.0-mm)depth with a standard drill point.7.2.3 Carefully prepare a flat-bottom drill or cutter withcutting edges square and flat within 0.0005 in. (0.013 mm) andperpendicular to its longitudinal
31、 axis (flatness, squareness, etc.,should be checked at a minimum of 60 magnification on anoptical comparator).7.2.4 Continue to drill as needed to remove all the conicalconfiguration of the bottom of the hole.7.2.5 Remove drill, check cutting edge, regrind, if neces-sary.7.2.6 Remove an additional 0
32、.005 in. (0.13 mm) of materialfrom the hole bottom.7.2.7 Recheck cutting edges of the drill on the opticalcomparator, regrind, if necessary, and repeat 7.2.5 and 7.2.6.Careful attention must be given to the squareness of corners ofthe cutter, the slightest radius reduces the reflective area of theho
33、le bottom.8. Checking Physical Characteristics8.1 All dimensions of the reference blocks including thediameter and perpendicularity of the examination hole may bechecked by normal quality control procedures for physicalmeasurements. The configuration, squareness, flatness, andsurface finish for hole
34、 bottoms364 in. (1.2 mm) in diameter andlarger may be checked by the following recommended tech-nique for making and evaluating plastic replicas:8.1.1 Clean hole with a suitable oil-free noncorrosive sol-vent and dry with a stream of dried and filtered air.8.1.2 Mix the replicating material in accor
35、dance with themanufacturers instructions.8.1.3 Force the material into the hole with a disposablemedical syringe and needle of adequate size.8.1.4 Fill the hole beginning at the bottom and graduallymoving outward making certain that no air pockets or bubblesremain in the hole.E428 08 (2013)28.1.5 In
36、sert a small wire, pin, needle, or other suitable objectthat will serve as a rigid core and facilitate removal of thereplica.8.1.6 After curing, the replica may be removed and exam-ined. The replica shall indicate that the hole bottom is flatwithin 0.001 in. (0.03 mm)/18 in. (3.2 mm) of diameter and
37、roughness shall not be greater than 16 rms finish. For recordpurposes, the replica may be projected on a comparator screenand photographed as shown in Fig. 2.9. Checking Ultrasonic Response Characteristics9.1 All measurements of area-amplitude and distance-amplitude characteristics are to be made us
38、ing a 5-MHz,38-in.(9.5-mm) flat transducer at a water path distance equal to themeasured distance to the last near-field maximum (Y0+) and apreviously linearity-calibrated test instrument. Referenceblocks that exhibit satisfactory external physical characteristicsand proper configuration of the repl
39、icated hole shall besubjected to additional examination to check their ultrasonic-response characteristics. If the ultrasonic-response characteris-tics are to be established by immersion techniques, the drilledflat-bottom holes shall be cleaned and temporarily plugged bya press-fit TFE-fluorocarbon
40、insert or sealed by some othersuitable technique to ensure a leak-tight closure. It is recom-mended that blocks fabricated as sets be compared with eachother to determine their relative ultrasonic-response character-istics. This is particularly desirable in the cases of setscontaining flat-bottom ho
41、les smaller than364 in. (1.2 mm) indiameter that cannot be satisfactorily replicated.9.2 Area/Amplitude Response CurvesAn area/amplitudeset may contain several blocks with same external dimensionsand distance from the entry surface to the selected FBHs ofvarying sizes. An area/amplitude-response cur
42、ve may be ob-tained by adjusting the examination sensitivity to give a signalwith an amplitude of 30 to 40 % of FSD from the block nearestthe middle of the range of the reflector sizes. Without changingany examination parameters, the ultrasonic response from theremaining blocks with both smaller and
43、 larger size reflectorsare plotted on the response curve. A typical area/amplitudecurve for a set of 4340 steel blocks is shown in Fig. 3. Anyblock that exhibits an erratic ultrasonic response and does notTABLE 1 Standard Block Sizes and Recommended Block SetsNOTE 1Material to be as specified by the
44、 user.NOTE 2All dimensions and tolerances are to be in accordance with Fig. 1.NOTE 31 in. = 25.4 mm.NOTE 4Block sets shown are typical of established commercial practice: more or fewer blocks may be required for specific applications.Metal Traveland DesignatorDistance/Amplitude,19 in each setBasic S
45、et,10 TotalArea/Amplitude Set, 8 TotalDiameter of Flat-Bottom Holes (164 in./1.6 mm) Dimension “D”Nomi-nalMTDim. “A”Desig. 3 5 8 3 5 8 1 2 3 4 5 6 7(in.) (in.) (mm)0.063 0.0625 1.6 0006 3 5 8 . . .0.125 0.125 3.2 0012 3 5 8 . 5 .0.250 0.250 6.4 0025 3 5 8 . 5 .0.375 0.375 9.5 0038 3 5 8 . . .0.500 0
46、.500 12.7 0050 3 5 8 . 5 .0.625 0.625 15.9 0062 3 5 8 . . .0.750 0.750 19.1 0075 3 5 8 . . .0.875 0.875 22.2 0088 3 5 8 . . .1.000 1.000 25.4 0100 3 5 8 . . .1.250 1.250 31.8 0125 3 5 8 . . .1.500 1.500 36.1 0150 . . . . 5 .1.750 1.750 44.5 0175 3 5 8 . . .2.000 2.000 50.8 0200 . . . . . .2.250 2.25
47、0 57.2 0225 3 5 8 . . .2.500 2.500 63.5 0250 . . . . . .2.750 2.750 69.9 0275 . . . . . .3.000 3.000 76.2 0300 3 5 8 3 5 8 1 2 3 4 5 6 73.250 3.250 82.6 0325 3 5 8 . . .3.500 3.500 88.9 0350 . . . . . .3.750 3.750 95.3 0375 3 5 8 . . .4.000 4.000 101.6 0400 . . . . . .4.250 4.250 106.0 0425 3 5 8 .
48、. .4.500 4.500 114.3 0450 . . . . . .4.750 4.750 120.7 -0475 3 5 8 . . .5.000 5.000 127.0 0500 . . . . . .5.250 5.250 133.4 0525 3 5 8 . . .5.500 5.500 139.7 0550 . . . . . .5.750 5.750 146.1 0575 . . . . . .6.000 6.000 152.4 0600 3 5 8 . 5 86.250 6.250 158.8 06256.500 6.500 165.1 0650E428 08 (2013)
49、3fall within the apparent normal area/amplitude-response curveis considered unsatisfactory and shall not be used. Modificationof the FBH to meet the required ultrasonic response is not anacceptable procedure.9.3 Distance/Amplitude Response CurvesA distance/amplitude set may contain a number of blocks with identicaldimensions and hole sizes but with varying distances from theentry surface to the FBHs. A distance/amplitude-responsecurve may be obtained by adjusting the test sensitivity to givea signal with an amplitude of 70 to 80 % of
