1、Designation: E1158 09E1158 14Standard 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 E1158; the number immediately following the designa
2、tion indicates 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. Scope Scope*1.1 This guide covers general
3、procedures for the material selection and fabrication of reference blocks made of metal or metalalloys and intended to be used for the examination of the same or similar production materials by pulsed longitudinal ultrasonicwaves applied perpendicular to the beam entry surface. Primary emphasis is o
4、n solid materials but some of the techniquesdescribed may be used for midwall examination of pipes and tubes of heavy wall thickness. Near-surface resolution in any materialdepends upon the characteristics of the instrument and search unit employed.1.2 This guide covers the fabrication of reference
5、blocks for use with either the immersion or the contact method of ultrasonicexamination.1.3 Reference blocks fabricated in accordance with this guide can be used to determine proper ultrasonic system operation.Area-amplitude and distance-amplitude curves can also be determined with these reference b
6、locks.1.4 This guide does not specify reference reflector sizes or product rejection limits. It does describe typical industry fabricationpractices and commonly applied tolerances where they lend clarity to the guide. In all cases of conflict between this guide andcustomer specifications, the custom
7、er specification shall prevail.1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.6 This standard does not purport to address the sa
8、fety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and health practices and to determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E127 Practice for Fabricating
9、and Checking Aluminum Alloy Ultrasonic Standard Reference Blocks3E428 Practice for Fabrication and Control of Metal, Other than Aluminum, Reference Blocks Used in Ultrasonic TestingE1316 Terminology for Nondestructive Examinations3. Terminology3.1 DefinitionsFor definitions of terms used in this gui
10、de, see Terminology E1316.4. Summary of Guide4.1 This guide describes a method of selecting suitable reference block material from current or previous production and thesubsequent fabrication and checking of the resulting ultrasonic reference blocks.1 This guide is under the jurisdiction of ASTM Com
11、mittee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic Method.Current edition approved June 1, 2009June 1, 2014. Published July 2009July 2014. Originally approved in 1990. Last previous edition approved in 20042009 asE1158 - 04.E1158 - 09. DOI: 10.
12、1520/E1158-09.10.1520/E1158-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The reference blocks in Prac
13、tice E127 are used to check the performance of ultrasonic examination equipment and for standardization and control of ultrasonicexaminations of aluminum alloy products. The ultrasonic response of the blocks in Practice E127 is evaluated against a standard target. The blocks described in this standa
14、rdare used for the examination of production material and may be used to establish accept-reject criteria.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be tech
15、nically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this
16、 standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This guide is intended to illustrate the fabrication of ultrasonic reference blocks that are representative of the productionmaterial to be examined.
17、Care in material selection and fabrication can result in the manufacture of reference blocks that areultrasonically similar to the production material thus eliminating the reference block as an examination variable.6. Material Selection6.1 It is good practice to use a sample removed from the product
18、ion lot of material as the reference block material. When thisis not possible the following guidelines should be followed.6.2 The reference block material should be of the same general shape and dimensions, surface finish, chemical composition, andmicrostructure as the production material to be exam
19、ined.6.3 To ensure that the material chosen is suitable for use as reference block material and is free of potentially interferingreflectors, ultrasonically examine the reference block material at the anticipated frequency and at a sensitivity that produces anacoustic noise level of 20 % screen heig
20、ht. The entire block should 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 from considerationas an ultrasonic reference block.6.4 Reference block material that meets the guidelines of 6.
21、3 should then be examined at a sensitivity that produces multiplereflections from the back surface (between 3 and 5 reflections in most metals and metal alloys). The production material shouldbe examined at the same sensitivity level to determine that the same number of back reflections are obtained
22、. This procedure mayhave to be repeated several times and an average number of back reflections determined in the case of some materials (see Note1).NOTE 1In some highly attenuative materials more than one or two back reflections may not be attainable. In these cases, selection of the referenceblock
23、 material may be based on similar acoustic noise levels from both the production material and that chosen for a reference block.7. Reference Block Configuration7.1 There are many different types of reference blocks used in industry depending upon the size and shape of the material tobe examined. Som
24、e of the more common flat bottom hole (FBH) types are described in 7.2 through 7.7, and shown in Figs. 1-7.An alternate method for fabricating FBHs is described in the annex.7.2 Fig. 1 shows the typical reference standards used for ultrasonic examination when the product to be examined consists ofla
25、rge round bar stock, between 1 to 10 in. (25.4 to 245.0 mm) in diameter. With such products it is often necessary to correct forthe loss of signal with increasing examination distance (distance-amplitude-correction, or DAC). Therefore, a stepped block, asshown in Fig. 1 is commonly used. This type o
26、f block is typically referred to as a distance-amplitude-block. It contains a numberof holes of the same size at various distances from the scan surface. A typical FBH size found in many such blocks is 564 in. (1.98mm) or larger depending upon the ultrasonic attenuation, or the internal structure of
27、 the product, or both. For even larger diameterbars the distance amplitude correction reference standard may contain even larger FBHs, possibly 14 in. (6.35 mm) or greater.7.3 To determine the linearity of the examination and to establish the quality level of the large-diameter product, (7.2), anare
28、a-amplitude reference block as shown in Fig. 2 is common. An area-amplitude-block contains holes of different cross-sectionalareas placed at the same distance from the scan surface. Typical hole sizes range from between 264 and 864 in. (0.79 and 3.18 mm)with even larger flat-bottom holes used in ref
29、erence blocks intended for use for the largest bars.7.4 For small round bar stock, typically 1 in. (25.4 mm) and under, a distance-amplitude block is normally not required. Thetypical area-amplitude block for this product is the same as for the larger diameter material as shown in Fig. 2, but on a s
30、mallerscale. The hole sizes typically range from between 264 and 564 in. (0.79 and 1.98 mm) for many metal and metal alloy products.7.5 When the product to be examined consists of large square or rectangular bar stock, the distance-amplitude reference blockis often of the type shown in Fig. 3. The t
31、ypical area-amplitude reference block is shown in Fig. 4. The reference block hole sizesare typically the same as those used for similar thickness round bars.NOTE 1All holes are the same diameter.FIG. 1 Typical Distance-Amplitude Reference Block Configuration for the Ultrasonic Testing of Large Meta
32、l and Metal Alloy Bars of from1 to 10 in. (25.4 to 254.0 mm) Diameter and LargerE1158 1427.6 The smaller sizes of square or rectangular bar stock, 1 in. (25.4 mm) and under in the direction of examination, often donot require the use of a distance-amplitude reference block. The area-amplitude block
33、may be similar to that shown in Fig. 4. Thereference block hole sizes are usually similar to those used for round bars of the same thickness.7.7 The reference blocks used for the ultrasonic examination of products with more complex geometries are normally fabricatedfrom production samples so that th
34、e effects of geometry variations are minimized.8. Fabrication Procedure8.1 Specific fabricating procedures are dependent upon the configuration of the reference block, the block composition, theexamination criticality, and even the skill of the machinists. Some general guidelines are given in 8.2 th
35、rough 8.3.2.NOTE 1Holes are of different diameters.FIG. 2 Typical Area-Amplitude Reference Block for use in Ultrasonic Testing of Round Bars as in Fig. 1NOTE 1All holes are the same diameter.FIG. 3 Typical Distance-Amplitude Reference Block for the Ultrasonic Testing of Large Square or Rectangular B
36、ars Greater than 1 in.(25.4 mm)NOTE 1Holes are of different diameters.FIG. 4 Typical Area-Amplitude Reference Block for the Ultrasonic Testing of Square or Rectangular BarsNOTE 1The finish and fitup of the mating surfaces strongly influence the success of the bond.FIG. 5 Typical Example of a Diffusi
37、on Bonded Reference Block for Small Diameter Round BarsE1158 1438.2 Flat-Bottom HolesFBHs should be drilled such that the hole bottom is perpendicular to the examining sound beam. Forthe fabrication of reference standards of the types shown in Figs. 1-4, a common procedure involves the drilling of t
38、he chosen holediameters to a desired depth using a conventional fluted drill bit. In Fig. 1 this depth would be 34 in. (19.05 mm). The fluted drillbit, or another of the same size, is carefully ground to remove the point and square the tip. An optical comparator or tool makersmicroscope is useful to
39、 determine when the point has been completely removed and the drill bit end is flat and square.8.2.1 The flattened drill bit is then used to carefully flatten the bottom of the drilled hole. This operation normally requires greatcare to avoid drill breakage while still ensuring that the hole bottom
40、is flat. A physicians ear examination microscope with a tipof the proper diameter is helpful in determining when the hole bottom is truly flat.8.2.2 If the ultrasonic examination is to be conducted with the product (and therefore the reference block) immersed in a liquid,it is considered good practi
41、ce to plug the holes in the reference block. Before plugging the holes it is important that the holes befree of debris and totally dry. Moisture, metal shavings, or both, can influence the ultrasonic response from the hole bottom.8.2.3 When using metal plugs, counter bores are machined in the block
42、to seat the plugs.An alternative method is to use plasticor rubber type sealant forced a short distance into the holes and allowed to harden.8.3 Diffusion Bonding MethodThe diffusion bonding technique offers an alternative method of reference block manufacture.With this method it is possible to fabr
43、icate reference blocks containing flat disc-shaped ultrasonic reflectors instead of FBHs. Inmany cases this permits the examination of the reference block from more than one direction thus enhancing the utility of the block.8.3.1 A typical example is shown in Fig. 5. A diffusion-bonded reference blo
44、ck for small diameter rounds could be fabricatedas shown. A section is removed from one of the round bars to be examined. The bar section is split lengthwise and both splitsurfaces are carefully ground.An end mill of the desired diameter is used to mill a shallow (typically 12 the hole diameter in d
45、epth)FBH in one of the split sections. The sections are then bonded back together using the diffusion bonding process. (The applicationof heat and pressure on the two sections for a period of time results in a sound diffusion bond which is indistinguishableultrasonically from the normal structure.)
46、(See Note 2.) The result is a reference standard that can be examined from either of 2sides.NOTE 2The time, temperature, and pressure requirements for a diffusion bond are both material and configuration dependent and therefore are beyondthe scope of this guide. The American Welding Society4 can fur
47、nish information on the subject.8.3.2 With developed skills, all of the reference blocks shown in Figs. 1-4 along with many more types can be successfullyfabricated using the diffusion bonding technique.9. Verification of Reflector Acceptability9.1 It is often desirable or required by specification,
48、 or both, that the FBHs be proven to be of the proper size and flatness. Ahole replication method is often used to measure these hole characteristics. This method, more often used for holes of 364 in. (1.19mm) or greater diameter, involves forcing a liquid rubber or plastic compound into the clean,
49、dry FBH hole, removing all entrapped4 Available from American Welding Society (AWS), 550 NW LeJeune Rd., Miami, FL 33126, http:/www.aws.org.NOTE 1The shape of the curve may differ as discussed in 10.1.FIG. 6 Typical Distance-Amplitude Ultrasonic Response CurveFIG. 7 Typical Area-Amplitude Ultrasonic Response CurveE1158 144air. When the material hardens it can be removed in the form of a plug or replica. This plug or hole replica can then be examinedfor the proper size and flatness. The removal of the hardened plug is facilitated if a small wire or oth
