1、 ISO 2015 Determination of the film thickness of coatings using an ultrasonic gage Dtermination de lpaisseur du feuil de revtement par mesurage ultrasons TECHNICAL SPECIFICATION ISO/TS 19397 Reference number ISO/TS 19397:2015(E) First edition 2015-12-15 ISO/TS 19397:2015(E)ii ISO 2015 All rights res
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3、ntranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightis
4、o.org www.iso.org ISO/TS 19397:2015(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 Terms and definitions . 1 4 Principle 3 5 Physical principles of the measuring method and of the application .3 6 Apparatus and materials 5 6.1 Ultrasonic film thickness measuring device 5 6.2 Couplant 5 6.3 Cal
5、ibration standards 5 7 Calibration, adjustment and checking of the measuring device .6 7.1 Calibration 6 7.2 Adjustment . 6 7.3 Checking the adjustment 6 8 Procedure of measurement . 6 9 Temperature influence during the measurement . 6 10 Precision . 7 10.1 General . 7 10.2 Repeatability limit 7 10.
6、3 Reproducibility limit 8 11 Test report . 9 Annex A (informative) Qualification of the personnel 10 Annex B (informative) Determination of precision .11 Bibliography .17 ISO 2015 All rights reserved iii Contents Page ISO/TS 19397:2015(E) Foreword ISO (the International Organization for Standardizat
7、ion) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be r
8、epresented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to
9、develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
10、 ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified dur
11、ing the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the m
12、eaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information The committee responsible for this document is ISO/TC
13、35, Paints and varnishes, Subcommittee SC 9, General test methods for paints and varnishes.iv ISO 2015 All rights reserved TECHNICAL SPECIFICATION ISO/TS 19397:2015(E) Determination of the film thickness of coatings using an ultrasonic gage 1 Scope This Technical Specification describes a method for
14、 determining the film thickness of coatings on metallic and non-metallic substrates using an ultrasonic gauge. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the ed
15、ition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4618, Paints and varnishes Terms and definitions 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 4618 and the following
16、 apply. 3.1 ultrasonic wave acoustic wave having a frequency higher than the range of audibility of the human ear, generally taken as higher than 20 kHz SOURCE: EN 1330-4:2010, 3.1.1 3.2 longitudinal wave compressional wave wave in which the particle motion in a material is in the same direction as
17、the propagation of the wave SOURCE: EN 1330-4:2010, 2.3.1 3.3 echo ultrasonic pulse reflected to the probe SOURCE: EN 1330-4:2010, 5.5.2 3.4 echo height echo amplitude height of an echo (3.3) indication on the screen SOURCE: EN 1330-4:2010, 5.5.5 3.5 ultrasonic impulse short-lived ultrasound signal
18、3.6 ultrasonic sensor ultrasonic probe device for sending and receiving ultrasonic waves (3.1), mostly based on piezoelectric materials ISO 2015 All rights reserved 1 ISO/TS 19397:2015(E) 3.7 acoustic impedance Z product of sound velocity and density of a material 3.8 reflection coefficient ratio of
19、 total reflected sound pressure to incident sound pressure at a reflecting surface SOURCE: EN 1330-4:2010, 3.4.11 Note 1 to entry: For a wave the reflection coefficient R is calculated from the acoustic impedances (3.7) Z 1and Z 2of the bordering media, for which 1 is the medium of the incoming soun
20、d: For a negative reflection coefficient the phase (3.9) of the reflected signal is changed by 180. 3.9 phase fraction of a complete wave cycle, expressed as an angle SOURCE: EN 1330-4:2010, 2.2.5 3.10 interface boundary between two media, in acoustic contact, having different acoustic impedances (3
21、.7) SOURCE: EN 1330-4:2010, 3.4.1 3.11 sound path travel time time needed for the sound path travel distance SOURCE: EN 1330-4:2010, 5.6.3 3.12 couplant coupling film medium interposed between the probe and the object under examination to enable the passage of ultrasonic waves (3.1)between them SOUR
22、CE: EN 1330-4:2010, 5.3.2 3.13 A-scan presentation display of the ultrasonic signal in which the X-axis represents the time and the Y-axis the amplitude SOURCE: EN 1330-4:2010, 5.5.16 Note 1 to entry: Ultrasonic film thickness measuring devices, besides the numerical values of the obtained film thic
23、knesses, normally display A-scans for checking the echo forms and echo sequences on a screen as well.2 ISO 2015 All rights reserved ISO/TS 19397:2015(E) 3.14 calibration operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement u
24、ncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication Note 1 to entry: A calibration may be expressed by a state
25、ment, calibration function, calibration diagram, calibration curve or calibration table. In some cases, it may consist of an additive or multiplicative correction of the indication with associated measurement uncertainty. Note 2 to entry: Calibration should not be confused with adjustment of a measu
26、ring system (3.15), often mistakenly called “self-calibration”, nor with verification of calibration. Note 3 to entry: Often, the first step alone in the above definition is perceived as being calibration. SOURCE: ISO/IEC Guide 99:2007, 2.39 3.15 adjustment of a measuring system adjustment set of op
27、erations carried out on a measuring system so that it provides prescribed indications corresponding to given values of a quantity to be measured Note 1 to entry: Types of adjustment of a measuring system include zero adjustment of a measuring system, offset adjustment and span adjustment (sometimes
28、called “gain adjustment”). Note 2 to entry: Adjustment of a measuring system should not be confused with calibration (3.14), which is a prerequisite for adjustment. Note 3 to entry: After adjustment of a measuring system, the measuring system normally should be recalibrated. SOURCE: ISO/IEC Guide 99
29、:2007, 3.11 3.16 working standard standard which is traceable to the national standard SOURCE: EN 60731:2007, 3.4.1.2 4 Principle The method described in this Technical Specification determines single film thicknesses from the times of flight of an ultrasonic impulse that is partially reflected at t
30、he interfaces of the coating system. The strengths and weaknesses of the method are shown by measuring data for the different film-substrate combinations that are relevant in practice. 5 Physical principles of the measuring method and of the application When measuring the film thickness using ultras
31、ound, longitudinal waves are used because they can be easily generated and can be coupled into a work piece with almost every liquid. As shown in Figure 1, a sensor (6) consists of a piezoelectric disc, for sound generation and for reception, and of a “delay path”. The ultrasonic impulse generated i
32、n the sensor first passes the delay path and then spreads through layers 1 to 3 down to the substrate (1) and beyond. On each interface, a fraction of the impinging ultrasonic wave is reflected as a new ultrasonic impulse, while another fraction passes through. The first reflection occurs in the ult
33、rasonic sensor when the ultrasonic impulse impinges on layer 1 (4). ISO 2015 All rights reserved 3 ISO/TS 19397:2015(E) 654321 Key 1 substrate 2 layer 3 3 layer 2 4 layer 1 5 couplant (liquid) 6 ultrasonic sensor (sender and receiver) E echo 1, 2, 3 Figure 1 Ultrasonic method Ultrasonic impulses are
34、 recorded when they are received in the ultrasonic sensor. The distances of time between the ultrasonic impulses correspond to the sound path travel times T i(i = 1, 2, 3) in the three individual layers. The amplitude or echo height of the ultrasonic impulse reflected on each interface depends on th
35、e respective reflection factors. If the sound velocity in each single layer is known, the respective film thickness can be calculated by means of the times of flight. For each layer, Formula (1) applies: /(1) where v is the sound velocity; t d is the dry film thickness; T is the sound path travel ti
36、me in the layer (back and forth). In order to be able to resolve echoes with short intervals of sound path travel times with the naked eye (e.g. 20 ns in a 20 m thick coating), the ultrasonic impulses shall be at least just as short. For this, the ultrasonic frequencies shall be respectively high (a
37、t least the reciprocal of half of the time of flight) or the A-scan shall be generated from lower frequencies by means of digital signal processing. For an example of an A-scan, see Figure 2. When layers are too thin, the echoes of the individual layers merge into each other. In this case, an optic
38、control of the evaluation in the A-scan presentation is no longer possible.4 ISO 2015 All rights reserved ISO/TS 19397:2015(E) In cases where the A-scan presentation shows positive and negative half-waves, it shall be taken into account that for a negative reflection factor (Z 2 Z 1 ) the phase of t
39、he ultrasonic impulse changes by 180. If this is ignored, a relative time delay of a half wavelength can occur. The precondition for ultrasonic impulses with signal amplitudes sufficiently high for evaluation forming at the interface of two layers is a sufficiently high reflection coefficient or res
40、pectively different acoustic impedances Z, and a clearly defined intersection between the materials. Otherwise, the reflections can become too low for detection. This can also occur with curved work pieces where, due to geometry, not all sound fractions simultaneously re-impinge from the interface o
41、n the sensor. T T T Key T sound path travel times for layers 1, 2, 3 E echo for layers 1, 2, 3 Figure 2 Example of an A-scan presentation 6 Apparatus and materials 6.1 Ultrasonic film thickness measuring device A device with an ultrasonic sensor for sending and receiving ultrasonic impulses and an e
42、valuation unit for determining the film thickness over the time of flight (see Figure 1). NOTE The ultrasonic sensors used for measuring the film thickness generate ultrasonic signals (longitudinal waves), which spread perpendicularly to the surface of the work piece and the coating. In the schemati
43、c diagram in Figure 1, a slant representation of the sound propagation was selected only for illustrating the sound generation. 6.2 Couplant An acoustic contact between probe and test specimen with sufficient coupling shall be enabled. Commonly, a liquid (e.g. water or oil) or a gel couplant is appl
44、ied. 6.3 Calibration standards For checking the function of a measuring device, a working standard shall be used. For checking the measuring method and for adjusting the device prior to use, a working measurement standard shall be used; one which largely corresponds to the respective test object to
45、be measured with regard to film thickness, coating system, substrate and thicknesses of the layers. ISO 2015 All rights reserved 5 ISO/TS 19397:2015(E) 7 Calibration, adjustment and checking of the measuring device 7.1 Calibration Calibrate the device in accordance with the manufacturers information
46、. NOTE Primarily, the time of flight of a signal is measured with the measuring devices. This time of flight can be checked, if necessary, with a calibration standard with defined thickness and known sound velocity. 7.2 Adjustment Adjust the device in accordance with the manufacturers information. W
47、hen adjusting the entering of sound velocities, it is recommended to use test specimens that are based on the minimum and maximum film thicknesses that would be expected for the determination of these sound velocities. Using the ultrasonic film thickness measuring device, the time of flight of the u
48、ltrasonic impulse and the sound velocities, in accordance with Formula (1), are determined in the same measuring area in which the film thickness was or will be determined with an alternative method. The determination of the time of flight is carried out repeatedly on each test specimen and the mean
49、 is taken for each test specimen. When selecting the test specimens to use for the determination of the sound velocity, it should be considered that the thinner the test specimens and the lower the sound path travel times, the more imprecise the determination of the sound velocity from time of flight and thickness. When calculating, it shall be observed that the data are entered in the units used by the manufacturer of the device and, after a calculation in SI units, th
