DIN EN 16813-2017 Thermal spraying - Measurement of the electrical conductivity of thermal sprayed non-iron metal coatings by means of eddy current method German version EN 16813 2.pdf

1、February 2017 English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 25.220.20!%ao%“2627602www.din.d

2、eDIN EN 16813Thermal spraying Measurement of the electrical conductivity of thermal sprayed noniron metal coatings by means of eddy current method;English version EN 16813:2016,English translation of DIN EN 16813:2017-02Thermisches Spritzen Messung der elektrischen Leitfhigkeit thermisch gespritzter

3、 NichteisenmetallSchichten mittels Wirbelstromverfahren;Englische Fassung EN 16813:2016,Englische bersetzung von DIN EN 16813:2017-02Projection thermique Mesurage de la conductivit lectrique des revtements mtalliques non ferreux obtenus par projection thermique, laide de la mthode par courants de Fo

4、ucault;Version anglaise EN 16813:2016,Traduction anglaise de DIN EN 16813:2017-02www.beuth.deDocument comprises 16 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.02.17 DIN EN 16813:2017-02 2 A comma is used as the decimal mark

5、er. National foreword This document has been prepared by Technical Committee CEN/TC 240 “Thermal spraying and thermally sprayed coatings” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was DIN-Normenausschuss Schweien und verwandte Verfahren (DIN Standards Commi

6、ttee Welding and Allied Processes), Working Committee NA 092-00-14 AA Thermisches Spritzen und thermisch gespritzte Schichten (DVS AG V 7). EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16813 November 2016 ICS 25.220.20 English Version Thermal spraying - Measurement of the electrical conducti

7、vity of thermal sprayed non-iron metal coatings by means of eddy current method Projection thermique - Mesurage de la conductivit lectrique des revtements mtalliques non ferreux obtenus par projection thermique, laide de la mthode par courants de Foucault Thermisches Spritzen - Messung der elektrisc

8、hen Leitfhigkeit thermisch gespritzter Nichteisenmetall-Schichten mittels Wirbelstromverfahren This European Standard was approved by CEN on 24 September 2016. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard t

9、he status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, Fre

10、nch, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria

11、, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey

12、 andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref.

13、 No. EN 16813:2016 EEN 16813:2016 (E) 2 Contents Page European foreword . 3 Introduction 4 1 Scope 5 2 Normative references 5 3 Terms and definitions . 5 4 Measuring process 6 4.1 Measuring method 6 4.2 Calibration standard 7 4.3 Measuring frequency and penetration depth . 8 4.4 Measuring instrument

14、s . 8 4.5 Factors, which have effects on the uncertainty of the measurement . 9 4.6 Limit of application 9 5 Procedure of the measurement 10 5.1 Calibration of the measuring instruments 10 5.2 Measurement . 10 6 Measuring results and their assessment . 10 7 Test report and documentation 11 Annex A (

15、informative) Record for the applied Electrical Conductivity Measurement 12 A.1 General . 12 A.2 Component/part . 12 A.3 Surface preparation for spraying . 12 A.4 Spraying procedure for component/part 12 A.5 Preparation of measurement 13 A.6 Measuring instrument 13 A.7 Result of the measured electric

16、al conductivity . 13 Bibliography . 14 DIN EN 16813:2017-02 EN 16813:2016 (E) 3 European foreword This document (EN 16813:2016) has been prepared by Technical Committee CEN/TC 240 “Thermal spraying and thermally sprayed coatings”, the secretariat of which is held by DIN. This European Standard shall

17、 be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2017, and conflicting national standards shall be withdrawn at the latest by May 2017. Attention is drawn to the possibility that some of the elements of this document may

18、be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgar

19、ia, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turk

20、ey and the United Kingdom. DIN EN 16813:2017-02 EN 16813:2016 (E) 4 Introduction In many applications, the electrical conductivity is a relevant technical parameter. For testing of imperfections in components or technological material properties the eddy current method can be very well applied. It c

21、an be detected or determined, for example: defects in welds; imperfections or change in the structure of a component, for example, due to aging processes in structures made out of aluminium; change in structure caused by temperature effects; thickness; physical material properties such as the electr

22、ical conductivity. Due to an interaction between high frequency magnetic fields, emitted from a measuring probe, and the eddy currents induced in the object to be measured the electrical conductivity can be determined, e.g. according to ASTM E 1004 or can be used for fast and contact less measuremen

23、ts of a coating thickness according to EN ISO 21968. Due to the manufacturing process thermal sprayed coatings contain a layer orientated structure. Dependent on the material used, it can also contain oxides and/or inclusions as well as porosity created due to splat boundary effects during spraying.

24、 Besides the structure with its grain boundaries, dislocations, internal stresses and impurities, e.g. oxide skins, the specific gravity of a material plays an important role for the level of the electrical conductivity. In order to produce the highest possible level of electrical conductivity in th

25、e coating, the influencing factors for the thermal spraying process should be minimized. DIN EN 16813:2017-02 EN 16813:2016 (E) 5 1 Scope This European standard specifies the procedure of the measurement of the electrical conductivity of non-Ferro-magnetic thermal sprayed coatings. By this measureme

26、nt the absolute value of the electrical conductivity in the coating sprayed on component can be determined as well as also deviations from the agreed rated value can be used to control a running production. With that, a remarkable contribution can be applied to process and quality assurance measures

27、 of a manufacture process. 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 edition cited applies. For undated references, the latest edition of the referenced do

28、cument (including any amendments) applies. EN ISO 21968, Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method (ISO 21968) 3 Terms and definitions For the purposes of this document, the following terms and

29、 definitions apply. 3.1 electrical conductivity physical value, which shows the ability of a material in this case of a thermal sprayed coating to conduct the current Note 1 to entry: It is defined to be the constant of proportionality between the current density and the electrical field intensity w

30、ithin the general Formula (1) of the ohmic law. is measured in S/m. =J E(1) where J is the current density; is the electrical conductivity; E is the field intensity. 3.2 electrical resistance R value, which defines the electrical voltage, which is needed that a certain current can flow through an el

31、ectrical conductor Note 1 to entry: The unit is ohm (). DIN EN 16813:2017-02 EN 16813:2016 (E) 6 3.3 specific electrical resistivity property of material, which is the result of the electrical resistance in a homogenous part with a constant current intensity distribution across the constant cross-se

32、ction and length of the conductor and an ohmic resistance Note 1 to entry: The specific electrical resistance, see Formula (2), depends on the temperature of material and is the reciprocal value of the electrical conductivity ( = 1/). The unit is ohm metre ( m). =ARL(2) where is the specific electri

33、cal resistivity in m; R is the ohmic resistance; A is the constant cross-section of the conductor; L is the length of the conductor. 4 Measuring process 4.1 Measuring method Measuring of the absolute value of the electrical conductivity takes place usually by a current voltage measurement. However,

34、this method is usually applied in laboratories only. If the electrical conductivity shall be determined in a component on site, primarily eddy current processes are applied. To measure the electrical conductivity of non-magnetic metals, such as aluminium, copper, brass, titanium, chrome-nickel-steel

35、, etc. Therefore, the phase-sensitive eddy current measurement procedure is very suitable. By that, the measuring probe fed from a generator with alternating current of a certain frequency is to be put to the object to be measured or to be brought into small distance to its surface. This exciter cur

36、rent generates a magnetic field of high frequency, which induces eddy currents in the material to be tested (in this case the coating respectively the base material), their intensity and penetration depth depend on its electrical conductivity. On the other hand the magnetic field induced by eddy cur

37、rents overlaps the generating field. The generated resulting magnetic field is detected by a measuring coil. By that, the induced voltage is a function of the electrical conductivity of the object to be measured and can be used as a signal for its measuring. See Figure 1. DIN EN 16813:2017-02 EN 168

38、13:2016 (E) 7 Key 1 ferrite core of the probe 4 measuring signal 2 exiting current 5 eddy current induced 3 high frequency magnetic alternating field 6 electrically conductive non-ferrous-alloy Figure 1 Phase-sensitive eddy current measuring method Using the phase-sensitive eddy current measurement

39、procedure the phase changing between exciter current and measuring signal is to be transferred into a conductivity value. This measuring value is independent from the distance between the probe and the coating surface for a certain arrangement, which depends on the type of the probe. By that, a non-

40、contactable determination of the conductivity can be applied also using this method, for example, below a varnish or a synthetic material coat. Using an adequate measuring frequency the influence of the surface roughness remains low. 4.2 Calibration standard Using the phase-sensitive eddy current me

41、asurement procedure the measuring value found in the component will be compared to the calibration standard as a reference standard, which conductivity is very well known. Standards for calibration of the measuring instrument are available for the whole conductivity range. Usually, they are also sup

42、plied from the measuring instrument producer. Because the calibration standards are subject to changes in properties due to use they have to be recalibrated at regular time periods or to be replaced. DIN EN 16813:2017-02 EN 16813:2016 (E) 8 4.3 Measuring frequency and penetration depth The penetrati

43、on depth of the eddy current is defined by the conductivity and the measuring frequency f. Generally, the penetration depth 0of the eddy current in a non-ferrous-alloy is given by: 0R503=f (3) where 0is the penetration depth of the eddy current in a non-ferrous-alloy; f is the measuring frequency in

44、 Hz; is the electrical conductivity in MS/m; Ris the permeability = 1 for non-magnetic materials. The penetration depth of the eddy current is also decisive for the minimally permissible thickness of the object to be measured. In order to achieve complete saturation within the coating to be measured

45、 a penetration depth Sshall be taken: s0= 2,5-3(4) where Sis the penetration depth of the eddy current in the coating; 0is the penetration depth of the eddy current in a non-ferrous-alloyl. Due to the usually low thickness of thermal sprayed coatings, a higher measuring frequency shall be taken, the

46、refore. Usually, such measuring frequencies are in the range of 480 kHz to more than 1 MHz. They are available in commercial instruments. Due to the increase of the skin effect with increasing frequency, however, the measuring frequency should not be selected unnecessary high, because the measuring

47、result could not be representative for the coating then. In the case of increasing measuring frequency the negative influence of surface roughness to the measuring result also increases. The higher the frequency the smoother should be the surface. Using the phase-sensitive eddy current measurement p

48、rocedure the effect remains low. 4.4 Measuring instruments Nowadays, instruments to measure the electrical conductivity are equipped as to be: independent instrument for control measurement in the laboratory; integrated instrument with an automatic measurement in installations for manufacture; hand-

49、operated instrument for measurements in the work shop. DIN EN 16813:2017-02 EN 16813:2016 (E) 9 Usually, the attachment contains: collection of measuring data and connections to PC, printer and to have the capability of data storing; measuring range: e.g. 0,5 MS/m to 65 MS/m respectively 1 % to 112 % IACS (International Annealed Copper Standard). Often a disturbing effect of distance variations can be suppressed when