Designation: E797/E797M – 10
Standard Practice for
Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact Method1 This standard is issued under the fixed designation E797/E797M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revis revision. ion. A number in parentheses parentheses indicates the year of last reapproval. reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
2.2 ASNT Documents:4 Nondestructive Testing Handbook , 2nd Editio Edition, n, Vol Vol 7 SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing ANSI/ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel 2.3 Aerospace Industries Industries Association Document: NAS-410 Certification and Qualification of Nondestructive Testing Personnel5
1. Sco Scope pe 1.1 Thi Thiss pra practic cticee2 prov provides ides guide guidelines lines for measur measuring ing the thickness of materials using the contact pulse-echo method at temperatures not to exceed 93°C (200°F). 1.2 This practice practice is app applica licable ble to any material material in whi which ch ultrasonic waves will propagate at a constant velocity throughout the part, and from which back reflections can be obtained and resolv resolved. ed. 1.3 Units—T —The he va valu lues es st state ated d in eit eithe herr SI un unit itss or in inch ch-pound pou nd uni units ts are to be reg regard arded ed sep separa arately tely as sta standa ndard. rd. The values valu es stat stated ed in each system system may not be exac exactt equ equiva ivalent lents; s; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard 1.4 This standar standard d doe doess not purport purport to add addre ress ss all of the safet sa fetyy co conc ncer erns ns,, if an anyy, as asso socia ciate ted d wi with th its us use. e. It is th thee responsibility of the user of this standard to establish appro priate safety and health practices and determine the applicability of regulatory limitations prior to use.
3. Terminology 3.1 Definitions—F —For or de defin finit itio ions ns of te term rmss us used ed in th this is practice, refer to Terminology E1316 Terminology E1316.. 4. Summ Summary ary of Practice Practice 4.1 Thickn Thickness ess (T ), ), when measured by the pulse-echo ultrasoni so nicc me meth thod od,, is a pr prod oduc uctt of th thee ve velo locit city y of so soun und d in th thee material and one half the transit time (round trip) through the material. T 5
2. Referenc Referenced ed Documents Documents 2.1 ASTM Standards:3 E317 Practice for Evalua Evaluating ting Perfo Performance rmance Characteristics Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without the Use of Electronic Measurement Instruments E494 Practice for Measuring Ultrasonic Velocity in Materials E543 Specification Specification for Agencies Perfo Performing rming Nonde Nondestrucstructive Testing E1316 Terminology for Nondestructive Examinations
where: thickne kness, ss, T = thic velocity y, and V = velocit t = tran transit sit tim time. e. 4.2 The pulse-echo pulse-echo ultrasonic ultrasonic instrument instrument measures the transit4. time of the ultrasonic pulse through the part. 4.3 3 The velo ve loci city ty in th the e ma mate teri rial al be bein ing g ex exam amin ined ed is a function of the physical properties of the material. It is usually assumed to be a constant for a given class of materials. Its approximate value can be obtained from Table X3.1 in Practice E494 or E494 or from the Nondestructive Testing Handbook , or it can be determined empirically. 4.4 4. 4 On Onee or mo more re re refe fere renc ncee bl bloc ocks ks ar aree re requ quir ired ed ha havi ving ng known velocity, or of the same material to be examined, and having hav ing thic thickne knesses sses accurately accurately mea measur sured ed and in the ran range ge of
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This practice is under the jurisdiction of ASTM Committee Committee E07 on Nondestructive Testing structive Testing and is the direct responsibility responsibility of Subc Subcommitt ommittee ee E07.06 on Ultrasonic Method. Current edition approved June 1, 2010. Published July 2010. Originally approved in 1981. Last previous edition approved in 2005 as E797 - 05. DOI: 10.1520/E079710. 2 For ASME Boiler and Pressure Vessel Code applications, see related Practice SE-797 in Section II of that Code. 3 For refere referenced nced ASTM stand standards, ards, visit the ASTM websi website, te, www www.astm .astm.org .org,, or contact ASTM Customer Service at
[email protected]. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.
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Available from American Society for Nondestructive Testing Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org. 5 Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA VA 22209-3928, http://www.aia-aerospace.org. http://www.aia-aerospace.org.
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E797/E797M – 10
NOTE 1—Slope of velocity conversion line is approximately that of steel. FIG. 1 Transit Time/Thickness Relationship
thicknesses to be measured. It is generally desirable that the thicknesses be “round numbers” rather than miscellaneous odd valu va lues es.. On Onee bl bloc ock k sh shou ould ld ha have ve a th thick ickne ness ss va valu luee ne near ar th thee maximum of the range of interest and another block near the minimum thickness. 4.5 The display element (A-scan display, display, meter meter,, or digital display) of the instrument must be adjusted to present convenient values of thickness dependent on the range being used. The con contro troll for this fun functio ction n may hav havee dif differ ferent ent nam names es on differentt instruments, including range, sweep, material standifferen
machined machin ed par parts, ts, and to det determ ermine ine wall thinning thinning in pro process cess equipment caused by corrosion and erosion. 5.3 Recomme Recommendatio ndations ns for determ determining ining the capabi capabilities lities and limitations of ultrasonic thickness gages for specific applications can be found in the cited references. 6,7
dardize, or velocity. 4.6 The timing circuits in dif different ferent instruments instruments use various conv co nver ersio sion n sc sche heme mes. s. A co comm mmon on met metho hod d is th thee so so-c -cal alled led time/ana time /analog log con conver versio sion n in whi which ch the time meas measure ured d by the instrument is converted into a proportional d-c voltage which is then applied to the readout device. Another technique uses a very high-frequency oscillator that is modulated or gated by the approp app ropria riate te ech echo o ind indicat ication ions, s, the out output put bei being ng use used d eith either er directly to suitable digital readouts or converted to a voltage for other presentation. A relationship of transit time versus thickness is shown graphically in Fig. 1. 1.
6.2 Personnel Qualification : tractua 6.2.1 6.2 .1 If spe specifi cified ed in the con contra ctuall agr agreeme eement, nt, per person sonnel nel performing examinations to this standard shall be qualified in accorda acco rdance nce wit with h a nat nation ionally ally or int intern ernatio ationall nally y rec recogn ognized ized NDT per person sonnel nel qua qualific lificatio ation n pra practic cticee or stan standar dard d suc such h as ANSI/ASNT ANSI/ ASNT CP-18 CP-189 9, SNT-TC-1A, SNT-TC-1A, NAS-410, NAS-410, or a si simil milar ar document and certified by the employer or certifying agency, as applicable. The practice or standard used and its applicable revisio rev ision n sha shall ll be iden identifie tified d in the con contra tractua ctuall agr agreeme eement nt between the using parties. 6.3 Qualification of Nondestructive Agencies—If specified in the contractual agreement, NDT agencies shall be qualified
6. Basis of Applica Application tion 6.1 The fol follow lowing ing items are sub subject ject to con contra tractu ctual al agr agreeeement between the parties using or referencing this practice.
5. Sign Significan ificance ce and Use 5.1 The techniques techniques described provide provide indire indirect ct measurement of thickness of sections of materials not exceeding temperatures of 93°C (200°F). Measurements are made from one side of the object, without requiring access to the rear surface. 5.2 Ultrasonic thickness measurements are used extensively on basic shapes and products of many materials, on precision
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Bosselaar Boss elaar,, H., and Goose Goosens, ns, J.C. J.C.J., J., “Method to Evalu Evaluate ate Direc Direct-Rea t-Reading ding
Ultrasonic Pulse-Echo Thickness Meters,” Materials Evaluation, March 1971, pp. 45–50. 7 Fowler, K.A., Elfbaum, G.M., Husarek, V., and Castel, J., “Applications of Precision Ultrasonic Thickness Gaging,” Proceedings of the Eighth World Conference on Nondestructive Testing, Cannes, France, Sept. 6–11, 1976, Paper 3F.5. --`,,```,,,,````-`-`,,`,,`,`,,`---
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E797/E797M – 10 and evaluated as described in Specification E543. E543. The applicable edition of Specification E543 shall be specified in the contractual agreement. 6.4 Procedures and Techniques—The procedures and techniques to be utilized shall be as specified in the contractual agreement. 6.5 Surface Surface Prep Preparatio aration n—The prepre-examin examination ation surf surface ace preparation criteria shall be specified in the contractual agreement.
8.1.1 Conditions—The display start is synchronized to the initial pulse. All display elements are linear. Full thickness is displayed on the A-scan display. 8.1. 8. 1.2 2 Under Under th thes esee co cond nditi ition ons, s, we can as assu sume me th that at th thee veloci vel ocity ty con conver versio sion n lin linee ef effec fective tively ly piv pivots ots abo about ut the ori origin gin (Fig. 1) 1). It may be necessary to subtract the wear-plate time, requiring minor use of delay control. It is recommended that standar stan dardiz dizatio ation n blo blocks cks pro provid viding ing a min minimu imum m of two thi thickckness ne sses es th that at sp span an th thee th thic ickn knes esss ra rang ngee be us used ed to ch chec eck k th thee
7. Appar Apparatus atus
full-range accuracy. 8.1.3 8.1 .3 Pla Place ce the search unit on a stan standar dardiz dizatio ation n blo block ck of known thickness with suitable couplant and adjust the instrumentt con men contro trols ls (ma (mater terial ial stan standar dardiz dizatio ation, n, ran range, ge, swe sweep, ep, or velocity) until the display presents the appropriate thickness reading. 8.1.4 The readings readings should then be checked and adjusted adjusted on standar stan dardiz dizatio ation n blo blocks cks with thi thickn ckness ess of less lesser er val value ue to improve the overall accuracy of the system. 8.2 Case II—Delay Line Single-Element Search Unit : 8.2.1 Conditions—When using this search unit, it is necessary that the equipment be capable of correcting for the time during which the sound passes through the delay line so that thee en th end d of th thee de dela lay y ca can n be ma made de to co coin inci cide de wi with th ze zero ro thickn thi ckness ess.. Thi Thiss req requir uires es a soso-call called ed “de “delay” lay” con contro troll in the
7.1 Instruments—Thick —Thicknessness-measur measurement ement instru instruments ments are divided into three groups: ( 1) Flaw detectors with an A-scan display readout, (2) Flaw detectors with an A-scan display and direct thickness readout, and (3) Direct thickness readout. 7.1.1 Flaw detectors with A-scan display readouts readouts displa display y time/ampl time/ amplitud itudee info informat rmation. ion. Thic Thickne kness ss dete determin rminatio ations ns are made by reading the distance between the zero-corrected initial pulse pul se and firs first-r t-retur eturned ned ech echo o (ba (back ck refl reflecti ection) on),, or betw between een multiple-back reflection echoes, on a standardized base line of the A-scan display. display. The base line of the A-sca A-scan n display should be adjusted for the desired thickness increments. 7.1.2 Flaw detectors detectors with numeric readout are a combin combinaation pulse ultrasound flaw detection instrument with an A-scan display and additional circuitry that provides digital thickness inform inf ormatio ation. n. The mate materia riall thi thickn ckness ess can be elec electro tronica nically lly measu mea sure red d an and d pr pres esen ente ted d on a di digi gital tal re read adou out. t. Th Thee AA-sc scan an disp di splay lay pr prov ovid ides es a ch check eck on th thee va valid lidity ity of th thee ele electr ctron onic ic measure meas uremen mentt by rev reveali ealing ng meas measure uremen mentt var variab iables, les, suc such h as interna inte rnall dis discon contin tinuiti uities, es, or ech echo-s o-stre trengt ngth h var variati iations ons,, whi which ch might result in inaccurate readings. 7.1.3 Thickn Thickness ess readout instruments instruments are modified versions of the pulse-echo instrument. The elapsed time between the initial pulse and the first echo or between multiple echoes is converted into a meter or digital readout. The instruments are design des igned ed for mea measur suremen ementt and dir direct ect num numeric erical al rea readou doutt of specific ranges of thickness and materials. 7.2 Searc —Mos ostt pu puls lsee-ech echo o ty type pe se sear arch ch un units its Search h Uni Units ts—M (str (s traig aight ht-b -bea eam m co cont ntac act, t, de delay lay lin line, e, an and d du dual al el elem emen ent) t) ar aree
instrument or automatic electronic sensing of zero thickness. 8.2.2 In most instruments, instruments, if the material standardize standardize circuit was previously adjusted for a given material velocity, the delay control should be adjusted until a correct thickness reading is obtained on the instrument. However, if the instrument must be comple com pletely tely stan standar dardiz dized ed wit with h the del delay ay lin linee sea search rch uni unit, t, the following follow ing techniq technique ue is recomm recommended ended:: 8.2.2.1 8.2.2 .1 Use at least two standardizatio standardization n blocks. One should have ha ve a th thic ickn knes esss ne near ar th thee ma maxi ximu mum m of th thee ra rang ngee to be measured and the other block near the minimum thickness. For convenience, it is desirable that the thickness should be “round numb nu mber ers” s” so th that at th thee di difffe fere renc ncee be betw tween een th them em als also o ha hass a convenient “round number” value. 8.2.2. 8.2 .2.2 2 Pla Place ce the search unit seq sequen uential tially ly on one and then the oth other er blo block, ck, and obt obtain ain bot both h rea readin dings. gs. The dif differ ference ence between these two readings should be calculated. If the reading thickness difference is less than the actual thickness difference, place the search unit on the thicker specimen, and adjust the material standardize control to expand the thickness range. If the read reading ing thi thickn ckness ess dif differ ferenc encee is gre greater ater tha than n the actu actual al thick th ickne ness ss di difffe fere renc nce, e, pl place ace th thee se sear arch ch un unit it on th thee th thic icke kerr specimen, and adjust the material standardize control to decrease the thickness thickness range. range. A certain amount amount of over correction correction is usually recommended. Reposition the search unit sequentially on both blocks, and note the reading differences while making additional appropriate corrections. When the reading thickness thickn ess dif differen ferential tial equals the actual thickn thickness ess dif differen ferential, tial, the mate materia riall thi thickn ckness ess ran range ge is cor correct rectly ly adj adjust usted. ed. A sin single gle adjust adj ustmen mentt of the del delay ay con contro troll sho should uld the then n per permit mit cor correc rectt readings at both the high and low end of the thickness range.
applicable if flaw detector instruments are used. If a thickness readout instrument has the capability to read thin sections, a highly damped, high-frequency search unit is generally used. High-frequency (10 MHz or higher) delay line search units are genera gen erally lly req requir uired ed for thi thickn ckness esses es less tha than n abo about ut 0.6 mm (0.025 (0.02 5 in.). Measurements Measurements of material materialss at high temperatures temperatures requir req uiree sear search ch uni units ts spe special cially ly des design igned ed for the app applica licatio tion. n. When Wh en du dual al ele eleme ment nt se sear arch ch un unit itss ar aree us used ed,, th their eir in inhe here rent nt nonlinearity usually requires special corrections for thin sections. tion s. (Se (Seee Fig. Fig. 2.) Fo Forr op optim timum um pe perf rfor orma manc nce, e, it is of often ten necessary that the instrument and search units be matched. 7.3 Standardization Blocks—The general requirements for approp app ropria riate te stan standar dardiz dizatio ation n blo blocks cks are giv given en in 4.4 4.4,, 8.1.3, 8.1.3, 8.2.2.1,, 8.3.2 8.2.2.1 8.3.2,, and 8.4.3 and 8.4.3.. Multi-step blocks that may be useful for these standardization procedures are described in Appendix X1 (Figs. X1.1 and X1.2) X1 X1.2).
8.2.3 An alternative alternative technique technique for delay line search units is a variation of that described in 8.2.2. 8.2.2. A series of sequential adjust adj ustmen ments ts are mad made, e, usi using ng the “de “delay lay”” con contro troll to pro provid videe correct readings on the thinner standardization block and the
8. Stand Standardi ardizati zation on of Apparatus Apparatus 8.1 Case I—Direct I—Direct Conta Contact, ct, Singl Single-Elem e-Element ent Sear Search ch Unit :
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E797/E797M – 10
(a ) Proportional sound path increases with decrease in thickness. (b ) Typ Typical ical reading error values values..
FIG. 2 Dual Transducer Nonlinearity
“range” control to correct the readings on the thicker block. Modera Mod erate te ove overr-cor correc rectio tion n is som sometim etimes es use useful ful.. Whe When n bot both h readings are “correct” the instrument is adjusted properly. 8.3 Case III—Dual Search Units: 8.3.1 The method describe described d in 8.2 in 8.2 (Case II) is also suitable for equipment using dual search units in the thicker ranges, above 3 mm (0.125 in.). However, below those values there is an inh inhere erent nt error due to the Vee Vee pat path h tha thatt the sound beam travels. The transit time is no longer linearly proportional to thick th ickne ness ss,, an and d th thee co cond nditi ition on de dete terio riora rates tes to towa ward rd th thee lo low w thick th ickne ness ss en end d of th thee ra rang nge. e. Th Thee va vari riati ation on is als also o sh show own n schematically in Fig. 2( 2(a). Typical error values are shown in Fig. 2( 2(b). 8.3.2 8.3 .2 If measurem measurement entss are to be made over a ver very y limi limited ted range near the thin end of the scale, it is possib possible le to standa standardize rdize the instrument with the technique in Case II using appropriate thin stan standar dardiz dizatio ation n blo blocks cks.. Thi Thiss will pro produc ducee a cor correc rection tion curve cur ve tha thatt is app approx roximat imately ely cor correc rectt ove overr tha thatt limi limited ted ran range. ge. Note that it will be substantially in error at thicker measurements. 8.3.3 8.3 .3 If a wid widee ran range ge of thi thickn ckness esses es is to be meas measure ured, d, it may be mo more re su suit itab able le to st stan anda dard rdize ize as in Cas Casee II us usin ing g standardization blocks at the high end of the range and perhaps
halfway toward the low end. Following this, empirical corrections can be established for the very thin end of the range. 8.3.4 8.3 .4 For a dir directect-rea readin ding g pan panelel-typ typee mete meterr dis displa play y, it is conven con venien ientt to bui build ld thes thesee cor correc rection tionss int into o the dis displa play y as a nonlinear function. 8.4 Case IV—Thick Sections: 8.4.1 Conditions—For use when a high degree of accuracy is required for thick sections. 8.4.2 Direct contact contact search unit and initial pulse synchronisynchronization are used. The display start is delayed as described in 8.4.4.. All 8.4.4 All dis displa play y elem element entss sho should uld be line linear ar.. Inc Increm rement ental al thickness is displayed on the A-scan display. 8.4.3 8.4 .3 Basi Basicc sta standa ndardi rdizati zation on of the sweep will be mad madee as described in Case I. The standardization block chosen for this standardization should have a thickness that will permit standardizing the full-sweep distance to adequate accuracy, that is, about 10 mm (0.4 in.) or 25 mm (1.0 in.) full scale. 8.4.4 8.4 .4 Aft After er bas basic ic sta standa ndardi rdizati zation, on, the swe sweep ep mus mustt be delayed. For instance, if the nomin nominal al part thickn thickness ess is expect expected ed to be from 50 to 60 mm (2.0 to 2.4 in.), and the basic standardization block is 10 mm (0.4 in.), and the incremental thickness displayed will also be from 50 to 60 mm (2.0 to 2.4 in.), the following steps are required. Adjust the delay control so that
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E797/E797M – 10 the fifth back echo of the basic standardization block, equivalent to 50 mm (2.0 in.), is aligned with the 0 reference on the A-scan display. The sixth back echo should then occur at the right edge of the standardized sweep. 8.4.5 This standardizati standardization on can be checked on a known block of the approximate total thickness. 8.4.6 The reading obtained obtained on the unkn unknown own specimen must be added to the value delayed off screen. For example, if the reading is 4 mm (0.16 in.), the total thickness will be 54 mm
different from the amplitude of the back reflection from the standar stan dardiz dizatio ation n blo blocks cks,, the thi thickn ckness ess rea readou doutt may rea read d to a differ dif ferent ent hal halff cyc cycle le in the wav wavetr etrain ain,, the thereb reby y pro produc ducing ing an error. This may be reduced by: 9.7.1 Using reference reference block blockss havin having g attenua attenuation tion charactercharacteristics equal to those in the measur measured ed material or adjus adjusting ting back reflecti refl ection on amp amplitu litude de to be equ equal al for bot both h the stan standar dardiz dizing ing blocks and measured material. 9.7.2 9.7 .2 Usi Using ng an ins instru trumen mentt wit with h aut automa omatic tic gai gain n con contro troll to
(2.16 in.). 9. Technical Hazards Hazards
produce a constant amplitude back reflection. 9.8 Readouts—A—A-scan scan dis displa plays ys are rec recomm ommend ended ed whe where re reflecting surfaces are rough, pitted, or corroded. 9.8.1 DirectDirect-thickn thickness ess reado readout, ut, withou withoutt an A-scan displa display y, presents hazards of misadjustment and misreading under certain test conditions, especially thin sections, rough corroded surfaces, and rapidly changing thickness ranges. 9.9 Reference Standards—Greater accuracy can be obtained when wh en th thee eq equi uipm pmen entt is st stan anda dard rdize ized d on ar area eass of kn know own n thickness of the material to be measured. 9.10 Variations in echo signal strength may produce an error error equiva equ ivalent lent to one or mor moree hal half-c f-cycle ycless of the RF fre freque quency ncy,, dependent on instrumentation characteristics.
9.1 Dual sea search rch units may also be use used d ef effec fective tively ly with rough surface conditions. In this case, only the first returned ech ec ho, su such ch as fro rom m th thee bot otto tom m of a pit it,, is use sed d in th thee measurement. Generally, a localized scanning search is made to detect the minimum remaining wall. 9.2 Material Pro —Thee ins instru trumen mentt sho should uld be sta stannProperties perties—Th dardized on a material having the same acoustic velocity and attenuation as the material to be measured. Where possible, standar stan dardiz dizatio ation n sho should uld be con confirm firmed ed by dir direct ect dim dimens ension ional al measurement of the material to be examined. 9.3 Scanning—The maximum speed of scanning should be stated in the procedure. Material conditions, type of equipment, and operator capabilities may require slower scanning. 9.4 Geometry: 9.4.1 Highes Highestt accuracy can be obtained from from materials with parallel or concentric surfaces. In many cases, it is possible to obtain measurements from materials with nonparallel surfaces. However, the accuracy of the reading may be limited and the reading obtained is generally that of the thinnest portion of the section being interrogated by the sound beam at a given instant. 9.4.2 Relative Relatively ly small-diameter small-diameter curves often require special techniq tech niques ues and equ equipm ipment ent.. Whe When n smal smalll diam diameter eterss are to be measured, special procedures including additional specimens may be required to ensure accuracy of setup and readout. 9.5 9. 5 High-t High-temp empera eratur turee mat mater erial ials, s, up to abo about ut 54 540° 0°C C (1000°F), can be measured with specially designed instruments with high-temperature compensation, search unit assemblies, and couplants. Normalization of apparent thickness readings for elevated temperatures is required. A rule of thumb often used is as follows: The apparent thickness reading obtained from fro m stee steell wall wallss hav having ing elev elevated ated tem temper peratu atures res is hig high h (to (too o thick) by a factor of about 1 % per 55°C (100°F). Thus, if the instrument was standardized on a piece of similar material at 20°C (68°F), and if the reading was obtained with a surface temperature tempera ture of 460° 460°C C (860 (860°F), °F), the appar apparent ent reading should be reduced by 8 %. This correction is an average one for many types of steel. Other corrections would have to be determined empirically for other materials. 9.6 Instrument —Time—Time-bas basee lin linear earity ity is req requir uired ed so that a change in the thickness of material will produce a corresponding in g ch chan ange ge of in indi dica cated ted thickn thickness ess.. If a CR CRT T is us used ed as a read re adou out, t, it itss ho hori rizo zont ntal al lin linea eari rity ty ca can n be ch chec ecke ked d by us usin ing g Practice E317 E317.. 9.7 Back Back Reflecti Reflection on Wavetra avetrain in—Direct —Direct-thick -thickness ness reado readout ut instru ins trumen ments ts rea read d the thicknes thicknesss at the first hal halff cyc cycle le of the wavetrain that exceeds a set amplitude and a fixed time. If the amplitude of the back reflection from the measured material is
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10. Procedur Proceduree Requirements Requirements 10.1 10. 1 In dev develop eloping ing the deta detailed iled pro procedu cedure, re, the fol follow lowing ing items should be considered: 10.1.1 10.1. 1 Instru Instrument ment manuf manufacturer acturer’s ’s opera operating ting instru instructions ctions 10.1.2 10.1. 2 Scope of materials/objec materials/objects ts to be measured 10.1.3 Applicability, accuracy requirements 10.1.4 10.1. 4 Definiti Definitions ons 10.1.5 10.1. 5 Requir Requirements ements 10.1.5.1 10.1. 5.1 Person Personnel nel 10.1.5.2 10.1. 5.2 Equip Equipment ment 10.1.5.3 10.1. 5.3 Proced Procedure ure qualifi qualification cation 10.1.5.4 10.1. 5.4 Trai Training ning or certific certification ation levels 10.1.6 10.1. 6 Proced Procedure ure 10.1.6.1 10.1. 6.1 Measur Measurement ement conditions conditions 10.1.6.2 10.1. 6.2 Surfa Surface ce prepar preparation ation and coupl couplant ant 10.1.6.3 10.1. 6.3 Standa Standardizati rdization on and allowable tolerances 10.1.6.4 10.1. 6.4 Scanni Scanning ng parameters 10.1.7 10.1. 7 Report 10.1.7.1 10.1. 7.1 Proced Procedure ure used 10.1.7.2 10.1. 7.2 Standa Standardizati rdization on recor record d 10.1.7.3 10.1. 7.3 Measur Measurement ement record 11. Repo Report rt 11.1 11 .1 Reco Record rd the following following informat information ion at the time of the measurements and include it in the report: 11.1.1 11 .1.1 Examin Examination ation procedure. 11.1.1.1 11 .1.1.1 Type of instru instrument. ment. 11.1.1.2 11 .1.1.2 Standa Standardizati rdization on blocks, size and material type. 11.1.1.3 11 .1.1.3 Size, frequency frequency, and type of search unit. 11.1.1.4 11 .1.1.4 Scanni Scanning ng method. 11.1.2 Results 11.1.2 Results.. 11.1.2.1 11 .1.2.1 Maximu Maximum m and minimum thickness measurements. measurements. 11.1.2.2 11 .1.2.2 Locatio Location n of measurements. measurements. 11.1.3 11 .1.3 Perso Personnel nnel data, certification level. 5 Not for Resale
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E797/E797M – 10 12. Keywo Keywords rds 12.1 con 12.1 contact tact exa examin minatio ation; n; nondes nondestru tructiv ctivee tes testing ting;; pul pulseseecho; thickn thickness ess measur measurement; ement; ultras ultrasonics onics
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E797/E797M – 10
APPENDIX (Nonmandatory Information) X1. Ty Typical pical Multi-Step Thickness Gage Reference Blocks
TABLE OF DIMENSIONS U.S.. Cus U.S Custom tomary ary Blo Block, ck, in. Metric Met ric Blo Block ck 5A, mm
Metric Met ric Blo Block ck 5B, mm
Legend Dimension Dimension Toleran olerance ce Dimens Dimension ion Toleran olerance ce Dimens Dimension ion Toleran olerance ce TABLE OF DIMENSIONS U.S.. Cus U.S Custom tomary ary Blo Block, ck, in. Metric Met ric Blo Block ck 4A, mm Legend Dimens Dimension ion Toleran olerance ce T1 T2 T3 T4 L W
0.250 0.500 0.750 1.000 0.75 0.75
0.001 0.001 0.001 0.001 0.02 0.05
Dimension Dimens ion 6.25 12.50 18.75 25.00 20.0 20.0
T1 T2 T3 T4 T5 L W
Metric Met ric Blo Block ck 4B, mm
Toleran olerance ce Dimens Dimension ion Toleran olerance ce 0.02 0.02 0.02 0.02 0.5 1.0
5.00 10.00 15.00 20.00 20.0 20.0
0.02 0.02 0.02 0.02 0.5 1.0
0.100 0.200 0.300 0.400 0.500 0. 0.75 0.75
0.001 0.001 0.001 0.001 0.001 0.02 0.05
2.50 5.00 7.50 10.00 12.50 20.0 20.0
0.02 0.02 0.02 0.02 0.02 0.5 1.0
2.00 4.00 6.00 8.00 10.00 20.00 20.00
0.02 0.02 0.02 0.02 0.02 0.5 1.0
NOTE 1—Material to be as specified. NOTE 2—Surface finish: “T” faces Ra 0.8 µm (32 µin.) max. Other surfaces Ra 1.6 µm (63 µin.) max. 16 in.) diameter through hole NOTE 3—Location for optional 1.5 mm ( 1 ⁄ 16 16 in.) from block used for block support during plating; center 1.5 mm (1 ⁄ 16 edges. NOTE 4—Al 4—Alll “T “T”” di dime mens nsio ions ns to be af afte terr an any y re requ quir ired ed pl plat atin ing g or anodizing. NOTE 5—In order to prevent sharp edges, minimize plating buildup, or remove rem ove inin-ser servic vicee nic nicks ks and bur burrs, rs, block edg edges es may be smo smooth othed ed by beveling or rounding, provided that the corner treatment does not reduce the edge dimension by more than 0.5 mm (0.020 in.). FIG. X1.2 Typical Five-Step Thickness Reference Blocks
NOTE 1—Material to be as specified. NOTE 2—Surfa 2—Surface ce fini finish: sh: “T” fac faces es Ra 0.8 µm (32 µin.) µin.) max max.. Oth Other er surfaces Ra 1.6 µm (63 µin.) max. 16 in.) diameter through hole NOTE 3—Loca 3—Location tion for optional 1.5 mm (1 ⁄ 16 16 in.) from block used for block support during plating; center 1.5 mm (1 ⁄ 16 edges. NOTE 4—Al 4—Alll “T “T”” di dime mens nsio ions ns to be af after ter an any y re requ quir ired ed pl plati ating ng or anodizing. NOTE 5—In order to prevent sharp edges, minimize plating buildup, or remove rem ove inin-ser servic vicee nic nicks ks and bur burrs, rs, block edg edges es may be sm smoot oothed hed by beveling bevelin g or rounding, provided provided that the corne cornerr treatm treatment ent does not reduce the edge dimension by more than 0.5 mm (0.020 in.). FIG. X1.1 Typical Four-Step Thickness Reference Blocks
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E797/E797M – 10
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