1、 Reference number ISO 25902-1:2009(E) ISO 2009INTERNATIONAL STANDARD ISO 25902-1 First edition 2009-02-01 Titanium pipes and tubes Non-destructive testing Part 1: Eddy-current examination Canalisations et tubes en titane Essai non destructif Partie 1: Contrle par courants de Foucault ISO 25902-1:200
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7、d iiiContents Page Foreword iv 1 Scope1 2 Normative reference1 3 Terms and definitions .1 4 General .2 4.1 Applicable dimension range.2 4.2 Summary of examination method2 4.3 Personnel .2 5 Apparatus.2 6 Reference piece .3 6.1 Purpose 3 6.2 Materials .3 6.3 Reference standards .3 6.4 Fabrication of
8、reference standards .5 6.5 Number and interval of reference standards5 7 Test method .5 7.1 Test frequency .5 7.2 Test coil 5 7.3 Settings.5 7.4 Confirmation of sensitivity of eddy-current test instrument 7 8 Acceptance criteria .7 9 Test report8 ISO 25902-1:2009(E) iv ISO 2009 All rights reservedFo
9、reword ISO (the International Organization for Standardization) 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 tec
10、hnical committee has been established has the right to be represented 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 o
11、f electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated
12、to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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 fo
13、r identifying any or all such patent rights. ISO 25902-1 was prepared by Technical Committee ISO/TC 79, Light metals and their alloys, Subcommittee SC 11, Titanium. ISO 25902 consists of the following parts, under the general title Titanium pipes and tubes Non-destructive testing: Part 1: Eddy-curre
14、nt examination Part 2: Ultrasonic examination for the detection of longitudinal flaws INTERNATIONAL STANDARD ISO 25902-1:2009(E) ISO 2009 All rights reserved 1Titanium pipes and tubes Non-destructive testing Part 1: Eddy-current examination 1 Scope This part of ISO 25902 specifies a method for the e
15、ddy-current examination, hereafter referred to as the “examination”, for detecting flaws in titanium seamless tubes and welded tubes, hereafter referred to as the “tubes”. Titanium tubes are now used as steam surface condensers in steam-power plants, anatomic-power plants and desalination plants. Th
16、erefore, the quality of titanium tubes is very important and this is why the eddy-current inspection method was established. This method also applies to titanium alloy tubes. In this part of ISO 25902 the minimum wall thickness is 0,3 mm, the rectangular groove and the drilled hole are permitted as
17、reference standards, as the outside diameter of the titanium tube increases, the detected flaw also increases. The limit of the outside diameter of the titanium tube is 38,1 mm. 2 Normative reference The following referenced document is indispensable for the application of this document. For dated r
18、eferences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 15548-1, Non-destructive testing Equipment for eddy current examination Part 1: Instrument characteristics and verification 3 Terms and definitions
19、 For the purposes of this document, the following terms and definitions apply. 3.1 straightening mark circumferentially spiral micro-dimensional variation which is generated by a straightening roll when a tube bend is straightened 3.2 ring mark circumferential-like micro-dimensional variation which
20、is generated by the stop of a roll when materials are cold rolled ISO 25902-1:2009(E) 2 ISO 2009 All rights reserved3.3 rough surface partial variation in roughness on the surface of a tube, which is the residue of a surface-finish trace 3.4 dent partial variation on the surface of a tube, which is
21、generated by mechanical shock 4 General 4.1 Applicable dimension range The range of the applicable dimensions of a tube shall be 10 mm to 150 mm outside diameter and 0, 3 mm to 10 mm thickness. 4.2 Summary of examination method The examination shall be carried out by using an encircling coil (hereaf
22、ter, referred to as the “test coil”). 4.3 Personnel This inspection shall be carried out by suitably trained operators and supervised by competent personnel nominated by the manufacturer. In the case of third-party inspection, this shall be agreed between the purchaser and manufacturer. 5 Apparatus
23、5.1 Test apparatus, composed of a flaw detector, a test coil, a tube feed device (including a coil-holding table), and an automatic alarm system or a recorder. 5.2 Eddy-current test instrument, composed of an oscillator, an electric device processing an electric signal, a display for signals resulti
24、ng from flaws or the like, etc. and shall be as follows. See Figure 1. a) The type, test frequency, the display system for indication, etc. shall conform to the purpose of the test. b) The eddy-current test instrument shall operate stably for long periods under fluctuations of 0 C to 40 C ambient te
25、mperature and 15 % supply voltage, and shall be protected against electric noise from the outside. Key 1 tube aSecondary 1. bPrimary. cSecondary 2. f Frequency. V Supply voltage. Figure 1 Simplified diagram of concentric coil technique ISO 25902-1:2009(E) ISO 2009 All rights reserved 35.3 Test coil,
26、 of a self-comparison type. 5.4 Tube feed device, automatic alarm system or recorder, with sufficient performance in flaw-detecting operation and acceptance criteria of the results. 5.5 Verification of apparatus for flaw detection. The performance of the apparatus for flaw detection shall be verifie
27、d by periodic examination and, if necessary, in accordance with ISO 15548-1. The apparatus for flaw detection shall have sufficient performance in flaw-detecting operation and judging operation of the results. 6 Reference piece 6.1 Purpose The reference piece shall be used for setting the sensitivit
28、y of the apparatus for flaw detection and examining whether the sensitivity is maintained at a necessary level or not. 6.2 Materials Materials to be used for the reference piece shall have at least the same material quality, nominal dimensions, and surface condition as those of the tubes to be exami
29、ned. 6.3 Reference standards 6.3.1 Classification and shapes of reference standards Reference standards used for a reference piece shall be classified as a rectangular groove or a drilled hole, and their shapes shall be as given in Figure 2. Furthermore, the symbol for the class of a reference stand
30、ard shall be N for the rectangular groove and D for the drilled hole. ISO 25902-1:2009(E) 4 ISO 2009 All rights reserveda) Rectangular groove b) Drilled hole Key aWidth of groove. bDepth. cLength of groove. dThickness. eAt most 10 % of length. fDiameter of drilled hole. Figure 2 Classification and s
31、hapes of reference standards 6.3.2 Dimensions of reference standards and tolerances thereon The reference-standard dimensions and tolerances shall be as given in Tables 1 and 2. Table 1 Dimensions of rectangular grooves and tolerances thereon Dimensions in millimetres Length Nominal class of rectang
32、ular groove Depth Tolerance on depth l Width N-0,10 0,10 N-0,20 0,20 0,05 N-0,40 0,40 N-12,5 12,5 % of thickness N-15 15,0 % of thickness N-20 20,0 % of thickness N-25 25,0 % of thickness N-30 30,0 % of thickness N-40 40,0 % of thickness 15 % (minimum value 0,05) 10 u l u 25 1,0 max. ISO 25902-1:200
33、9(E) ISO 2009 All rights reserved 5Table 2 Size of drilled holes and tolerance thereon Diameter of hole Tolerance on diameter Nominal class of drilled hole mm mm D-0,8 0,8 D-1,0 1,0 D-1,2 1,2 D-1,4 1,4 D-1,6 1,6 0,05 D-3,2 3,2 0,1 6.4 Fabrication of reference standards The reference standards (notch
34、/drill hole) shall be fabricated as follows: a) for seamless tubes: formed by electric-discharge machining or mechanical machining; b) for welded tubes: formed by electric-discharge machining or mechanical machining on the base-metal part of the tube. 6.5 Number and interval of reference standards T
35、he following conditions shall apply. a) There shall be one or more angular grooves positioned axially on the outer surface of the tube. b) There shall be three drilled holes in the axial direction of a tube at intervals and each at 120 on the peripheral direction of the tube. The drilled hole shall
36、be opened by vertically piercing the surface of the tube. c) Each interval of reference standards and each distance from the end of a reference piece shall be such that the signal of the reference standard can be sufficiently separately detected at the speed to be examined. 7 Test method 7.1 Test fr
37、equency The test frequency shall be within the range of 1 kHz to 512 kHz, and a frequency capable of detecting sufficiently the reference standard of a reference piece shall be used. 7.2 Test coil The test coil shall have a shape, system and dimensions so that reference standards of the reference pi
38、ece to be used for setting sensitivity can be sufficiently detected. 7.3 Settings 7.3.1 Period for setting flaw-detection sensitivity The flaw-detection sensitivity shall be set before the start of the examination. ISO 25902-1:2009(E) 6 ISO 2009 All rights reserved7.3.2 Reference standards for setti
39、ng flaw-detection sensitivity For reference standards to be used for setting flaw-detection sensitivity, Table 3 applies to tubes with an outside diameter of at most 38,1 mm and Table 4 applies to tubes with an outside diameter of over 38,1 mm. The division given in the Tables is selected according
40、to the use of a tube, manufacturing method, finishing method and thickness, and either a rectangular groove or a drilled hole shall be used. Table 3 Reference standards for setting flaw-detection sensitivity (38,1 mm max. outside diameter) Application Classification of reference standards to be used
41、 Thickness t Division Use Manufacturing method Finishing method mm Nominal of rectangular groove Nominal of drilled hole 0,3 u t 0,8 N-0,10 EA Welded tube As-welded or cold drawing 0,8 u t 3 N-12,5 D-0,8 1 u t 1,3 N-0,20 EB For heat exchanger Seamless tube Cold drawing 1,3 u t 5 N-15 D-1,0 EC Welded
42、 tube As-welded or cold drawing 1 u t u 10 N-20 D-1,2 ED Cold drawing 1 u t u 10 N-25 D-1,4 For piping Hot extrusion 3 u t u 10 N-30 1 u t 1,3 N-0,40 EE For heat exchanger and for piping Seamless tube Cold rolling 1,3 u t u 10 N-30 D-1,6 Table 4 Reference standards for setting flaw-detection sensiti
43、vity (over 38,1 mm outside diameter) Application Classification of reference standards to be used Thickness t Division Use Manufacturing method Finishing method mm Nominal of rectangular groove Nominal of drilled hole 0,3 u t 1,3 N-0,20 EF Welded tube As-welded or cold drawing 1,3 u t 3 N-15 D-1,0 E
44、G For heat exchanger Seamless tube Cold drawing 1 u t 5 N-20 D-1,2 EH Welded tube As-welded or cold drawing 1 u t u 10 N-25 D-1,4 EI For piping Cold drawing 1 u t u 10 N-30 D-1,6 Hot extrusion 3 u t u 10 EJ For heat exchanger and for piping Seamless tube Cold rolling 1 u t u 10 N-40 D-3,2 ISO 25902-
45、1:2009(E) ISO 2009 All rights reserved 77.3.3 Adjustment of eddy-current test instrument The sensitivity, phase, etc. of an eddy-current test instrument shall be adjusted with the reference piece of the division selected from Table 3 or Table 4. The sensitivity of the eddy-current test instrument sh
46、all be adjusted so that the indication by the reference standard of the reference piece becomes almost 50 % of the scale range of the recorder, indicator, etc. The display, automatic alarm system, or recorder of the eddy-current test instrument shall be adjusted so that the indication by reference s
47、tandards falls within a normal operation range during the travelling state of the reference piece. 7.3.4 Adjustment of tube feed device The tube feed device shall be regulated so that dispersion of the signal of the reference standard is detected within a range of 15 % when the test coil is passed a
48、t a speed to be examined by varying the position of the reference standard of a reference piece at each 90 for a rectangular groove, or with the reference standard formed at each 120 on the periphery of the tube of the reference piece for a drilled hole. 7.4 Confirmation of sensitivity of eddy-curre
49、nt test instrument It shall be confirmed at least every 4 h that the sensitivity of the eddy-current test instrument is suitably maintained when examining the end of each operation, when the examination is interrupted and when the examination is continuously performed. Where an abnormality of the apparatus is discovered during the eddy-current test instrument examination, readjustment is performed and all tubes examined during the abnormal period shall be re-examined. 8 Acceptance cri
