1、Designation: E 1158 09Standard Guide forMaterial Selection and Fabrication of Reference Blocks forthe Pulsed Longitudinal Wave Ultrasonic Testing of Metaland Metal Alloy Production Material1This standard is issued under the fixed designation E 1158; the number immediately following the designation i
2、ndicates the year oforiginal adoption 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.1. Scope1.1 This guide covers general procedures fo
3、r the materialselection and fabrication of reference blocks made of metal ormetal alloys and intended to be used for the examination of thesame or similar production materials by pulsed longitudinalultrasonic waves applied perpendicular to the beam entrysurface. Primary emphasis is on solid material
4、s but some of thetechniques described may be used for midwall examination ofpipes and tubes of heavy wall thickness. Near-surface resolu-tion in any material depends upon the characteristics of theinstrument and search unit employed.1.2 This guide covers the fabrication of reference blocks foruse wi
5、th either the immersion or the contact method ofultrasonic examination.1.3 Reference blocks fabricated in accordance with thisguide can be used to determine proper ultrasonic systemoperation. Area-amplitude and distance-amplitude curves canalso be determined with these reference blocks.1.4 This guid
6、e does not specify reference reflector sizes orproduct rejection limits. It does describe typical industryfabrication practices and commonly applied tolerances wherethey lend clarity to the guide. In all cases of conflict betweenthis guide and customer specifications, the customer specifica-tion sha
7、ll prevail.1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 This standard does not purport to address the safetyconcerns, if any,
8、associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and to determine the applicability of regula-tory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 127 Practice for Fabricating and Checking Aluminum
9、Alloy Ultrasonic Standard Reference Blocks3E 428 Practice for Fabrication and Control of Metal, Otherthan Aluminum, Reference Blocks Used in UltrasonicTestingE 1316 Terminology for Nondestructive Examinations3. Terminology3.1 DefinitionsFor definitions of terms used in this guide,see Terminology E 1
10、316.4. Summary of Guide4.1 This guide describes a method of selecting suitablereference block material from current or previous productionand the subsequent fabrication and checking of the resultingultrasonic reference blocks.5. Significance and Use5.1 This guide is intended to illustrate the fabric
11、ation ofultrasonic reference blocks that are representative of theproduction material to be examined. Care in material selectionand fabrication can result in the manufacture of reference1This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-tive Testing and is the direct responsib
12、ility of Subcommittee E07.06 on UltrasonicMethod.Current edition approved June 1, 2009. Published July 2009. Originally approvedin 1990. Last previous edition approved in 2004 as E 1158 - 04.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
13、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The reference blocks in Practice E 127 are used to check the performance ofultrasonic examination equipment and for standardization and control of ultrasonicexaminations
14、 of aluminum alloy products. The ultrasonic response of the blocks inPractice E 127 is evaluated against a standard target. The blocks described in thisstandard are used for the examination of production material and may be used toestablish accept-reject criteria.1Copyright ASTM International, 100 B
15、arr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.blocks that are ultrasonically similar to the production materialthus eliminating the reference block as an examination vari-able.6. Material Selection6.1 It is good practice to use a sample removed from theproduction lot
16、 of material as the reference block material.When this is not possible the following guidelines should befollowed.6.2 The reference block material should be of the samegeneral shape and dimensions, surface finish, chemical com-position, and microstructure as the production material to beexamined.6.3
17、 To ensure that the material chosen is suitable for use asreference block material and is free of potentially interferingreflectors, ultrasonically examine the reference block materialat the anticipated frequency and at a sensitivity that producesan acoustic noise level of 20 % screen height. The en
18、tire blockshould be scanned from the surface which will be used forstandardization. Any discrete indication that exceeds 40 %screen height should be cause to remove the material fromconsideration as an ultrasonic reference block.6.4 Reference block material that meets the guidelines of6.3 should the
19、n be examined at a sensitivity that producesmultiple reflections from the back surface (between 3 and 5reflections in most metals and metal alloys). The productionmaterial should be examined at the same sensitivity level todetermine that the same number of back reflections areobtained. This procedur
20、e may have to be repeated several timesand an average number of back reflections determined in thecase of some materials (see Note 1).NOTE 1In some highly attenuative materials more than one or twoback reflections may not be attainable. In these cases, selection of thereference block material may be
21、 based on similar acoustic noise levelsfrom both the production material and that chosen for a reference block.7. Reference Block Configuration7.1 There are many different types of reference blocks usedin industry depending upon the size and shape of the materialto be examined. Some of the more comm
22、on flat bottom hole(FBH) types are described in 7.2 through 7.7, and shown inFigs. 1-7. An alternate method for fabricating FBHs isdescribed in the annex.7.2 Fig. 1 shows the typical reference standards used forultrasonic examination when the product to be examinedconsists of large round bar stock,
23、between 1 to 10 in. (25.4 to245.0 mm) in diameter. With such products it is often necessaryto correct for the loss of signal with increasing examinationdistance (distance-amplitude-correction, or DAC). Therefore, astepped block, as shown in Fig. 1 is commonly used. This typeof block is typically ref
24、erred to as a distance-amplitude-block.It contains a number of holes of the same size at variousdistances from the scan surface. A typical FBH size found inmany such blocks is564 in. (1.98 mm) or larger dependingupon the ultrasonic attenuation, or the internal structure of theproduct, or both. For e
25、ven larger diameter bars the distanceamplitude correction reference standard may contain evenlarger FBHs, possibly14 in. (6.35 mm) or greater.7.3 To determine the linearity of the examination and toestablish the quality level of the large-diameter product, (7.2),an area-amplitude reference block as
26、shown in Fig. 2 iscommon. An area-amplitude-block contains holes of differentcross-sectional areas placed at the same distance from the scansurface. Typical hole sizes range from between264 and864 in.(0.79 and 3.18 mm) with even larger flat-bottom holes used inreference blocks intended for use for t
27、he largest bars.7.4 For small round bar stock, typically 1 in. (25.4 mm) andunder, a distance-amplitude block is normally not required. Thetypical area-amplitude block for this product is the same as forthe larger diameter material as shown in Fig. 2, but on a smallerscale. The hole sizes typically
28、range from between264 and564in. (0.79 and 1.98 mm) for many metal and metal alloyproducts.NOTE 1All holes are the same diameter.FIG. 1 Typical Distance-Amplitude Reference Block Configurationfor the Ultrasonic Testing of Large Metal and Metal Alloy Bars offrom 1 to 10 in. (25.4 to 254.0 mm) Diameter
29、 and LargerNOTE 1Holes are of different diameters.FIG. 2 Typical Area-Amplitude Reference Block for use inUltrasonic Testing of Round Bars as in Fig. 1NOTE 1All holes are the same diameter.FIG. 3 Typical Distance-Amplitude Reference Block for theUltrasonic Testing of Large Square or Rectangular Bars
30、 Greaterthan 1 in. (25.4 mm)NOTE 1Holes are of different diameters.FIG. 4 Typical Area-Amplitude Reference Block for the UltrasonicTesting of Square or Rectangular BarsE11580927.5 When the product to be examined consists of largesquare or rectangular bar stock, the distance-amplitude refer-ence bloc
31、k is often of the type shown in Fig. 3. The typicalarea-amplitude reference block is shown in Fig. 4. The refer-ence block hole sizes are typically the same as those used forsimilar thickness round bars.7.6 The smaller sizes of square or rectangular bar stock, 1in. (25.4 mm) and under in the directi
32、on of examination, oftendo not require the use of a distance-amplitude reference block.The area-amplitude block may be similar to that shown in Fig.4. The reference block hole sizes are usually similar to thoseused for round bars of the same thickness.7.7 The reference blocks used for the ultrasonic
33、 examina-tion of products with more complex geometries are normallyfabricated from production samples so that the effects ofgeometry variations are minimized.8. Fabrication Procedure8.1 Specific fabricating procedures are dependent upon theconfiguration of the reference block, the block composition,
34、 theexamination criticality, and even the skill of the machinists.Some general guidelines are given in 8.2 through 8.3.2.8.2 Flat-Bottom HolesFBHs should be drilled such thatthe hole bottom is perpendicular to the examining sound beam.For the fabrication of reference standards of the types shown inF
35、igs. 1-4, a common procedure involves the drilling of thechosen hole diameters to a desired depth using a conventionalfluted drill bit. In Fig. 1 this depth would be34 in. (19.05 mm).The fluted drill bit, or another of the same size, is carefullyground to remove the point and square the tip. An opti
36、calcomparator or tool makers microscope is useful to determinewhen the point has been completely removed and the drill bitend is flat and square.8.2.1 The flattened drill bit is then used to carefully flattenthe bottom of the drilled hole. This operation normally requiresgreat care to avoid drill br
37、eakage while still ensuring that thehole bottom is flat. A physicians ear examination microscopewith a tip of the proper diameter is helpful in determining whenthe hole bottom is truly flat.8.2.2 If the ultrasonic examination is to be conducted withthe product (and therefore the reference block) imm
38、ersed in aliquid, it is considered good practice to plug the s in thereference block. Before plugging the holes it is important thatthe holes be free of debris and totally dry. Moisture, metalshavings, or both, can influence the ultrasonic response fromthe hole bottom.8.2.3 When using metal plugs, c
39、ounter bores are machinedin the block to seat the plugs. An alternative method is to useplastic or rubber type sealant forced a short distance into theholes and allowed to harden.8.3 Diffusion Bonding MethodThe diffusion bondingtechnique offers an alternative method of reference blockmanufacture. Wi
40、th this method it is possible to fabricatereference blocks containing flat disc-shaped ultrasonic reflec-tors instead of FBHs. In many cases this permits the exami-nation of the reference block from more than one direction thusenhancing the utility of the block.8.3.1 A typical example is shown in Fi
41、g. 5. A diffusion-bonded reference block for small diameter rounds could befabricated as shown. A section is removed from one of theround bars to be examined. The bar section is split lengthwiseand both split surfaces are carefully ground. An end mill of thedesired diameter is used to mill a shallow
42、 (typically12 the holediameter in depth) FBH in one of the split sections. Thesections are then bonded back together using the diffusionbonding process. (The application of heat and pressure on thetwo sections for a period of time results in a sound diffusionbond which is indistinguishable ultrasoni
43、cally from the normalNOTE 1The finish and fitup of the mating surfaces strongly influencethe success of the bond.FIG. 5 Typical Example of a Diffusion Bonded Reference Blockfor Small Diameter Round BarsNOTE 1The shape of the curve may differ as discussed in 10.1.FIG. 6 Typical Distance-Amplitude Ult
44、rasonic Response CurveFIG. 7 Typical Area-Amplitude Ultrasonic Response CurveE1158093structure.) (See Note 2.) The result is a reference standard thatcan be examined from either of 2 sides.NOTE 2The time, temperature, and pressure requirements for adiffusion bond are both material and configuration
45、dependent and there-fore are beyond the scope of this guide. The American Welding Society4can furnish information on the subject.8.3.2 With developed skills, all of the reference blocksshown in Figs. 1-4 along with many more types can besuccessfully fabricated using the diffusion bonding technique.9
46、. Verification of Reflector Acceptability9.1 It is often desirable or required by specification, or both,that the FBHs be proven to be of the proper size and flatness.A hole replication method is often used to measure these holecharacteristics. This method, more often used for holes of364in. (1.19 m
47、m) or greater diameter, involves forcing a liquidrubber or plastic compound into the clean, dry FBH hole,removing all entrapped air. When the material hardens it can beremoved in the form of a plug or replica. This plug or holereplica can then be examined for the proper size and flatness.The removal
48、 of the hardened plug is facilitated if a small wireor other object is inserted into the hole while the replicatingmaterial is still liquid. When the replicating material solidifiesthe wire serves as a handle permitting easy removal of the plug.9.2 Replication of the disc-shaped reflector in diffusi
49、onbonded reference blocks is not possible. An alternative methodof determining whether the reflector has been distorted by thebonding process is to fabricate a second block under identicalconditions for destructive examination at the conclusion of theprocess.10. Ultrasonic Response Characteristics10.1 If the fabrication procedure, either drilling or diffusionbonding, was sufficiently accurate, then the distance amplitudereference block set may yield an ultrasonic response curvesimilar to that shown in Fig. 6. The shape of the curve maydiffer significantly w
