《BS-ISO-24497-3-2007.pdf》由会员分享，可在线阅读，更多相关《BS-ISO-24497-3-2007.pdf（20页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS ISO 24497-3:2007 Non-destructive testing Metal magnetic memory Part 3: Inspection of welded joints ICS 25.160.40 ? Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI BS ISO 24497-3:2007 This Br
2、itish Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 2007 ISBN 978 0 580 55672 2 National foreword This British Standard is the UK implementation of ISO 24497-3:2007. The UK participation in its preparation was entrusted to Technical
3、 Committee WEE/46, Non-destructive testing. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a
4、 British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI Reference number ISO 24497-3:2007(E) IN
5、TERNATIONAL STANDARD ISO 24497-3 First edition 2007-11-01 Non-destructive testing Metal magnetic memory Part 3: Inspection of welded joints Essais non destructifs Mmoire magntique des mtaux Partie 3: Examen des assemblages souds BS ISO 24497-3:2007 Licensed Copy: London South Bank University, London
6、 South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI iii Contents Page Foreword iv 1 Scope . 1 2 Basic principles 1 3 Inspect
7、ion conditions. 2 4 Inspection devices 2 5 Inspection planning 3 6 Inspection procedure . 4 7 Processing of results . 5 Annex A (normative) Inspection report 7 Annex B (informative) Example of stress concentration zones defined by a device with digital indication of the magnetic field intensity. 9 A
8、nnex C (informative) An example of stress concentration zones defined by the device having recorder and scanner. 11 BS ISO 24497-3:2007 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI iv Foreword ISO (the Inter
9、national 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 technical committee has
10、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 of electrotechnical st
11、andardization. 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 to the member bodies
12、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 for identifying any or
13、all such patent rights. ISO 24497-3 was prepared by the International Institute of Welding, Commission V, Quality control and quality assurance of welded products, recognized as an international standardizing body in the field of welding in accordance with Council Resolution 42/1999. Requests for of
14、ficial interpretations of any aspect of this part of ISO 24497 should be directed to the ISO Central Secretariat, who will forward them to the IIW Secretariat for an official response. ISO 24497 consists of the following parts, under the general title Non-destructive testing Metal magnetic memory: P
15、art 1: Vocabulary Part 2: General requirements Part 3: Inspection of welded joints BS ISO 24497-3:2007 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI 1 Non-destructive testing Metal magnetic memory Part 3: Ins
16、pection of welded joints 1 Scope This part of ISO 24497 specifies the general requirements for the application of the metal magnetic memory inspection method (MMM inspection) as a non-destructive testing method for quality assurance of welded joints of pressurized components. This part of ISO 24497
17、may be applied to welded joints in any type of products, pipelines, vessels, equipment, and metal constructions, as agreed with the purchaser. The terms and definitions for the process are contained in ISO 24497-1, and the general requirements of the process are in ISO 24497-2. 2 Basic principles 2.
18、1 inspection is based on measurement and analysis of the distribution of self-magnetic-leakage fields (SMLF) in the material of welded joints reflecting their technological history. Natural magnetization, induced during the welding process in the Earths magnetic field, is used for the inspection. 2.
19、2 inspection permits the detection of mechanical stress concentration zones (SCZ) and gives recommendations for additional non-destructive inspections in critical zones of vessels, pipelines, equipment, and construction welded joints. 2.3 inspection is complementary in its capability to other well-k
20、nown non-destructive testing methods (ultrasonic inspection, magnetic particle inspection, liquid penetrant inspection, and hardness testing). 2.4 inspection allows the testing of welded joints of any size and configuration (butt, tee, fillet, lap, edge, intermittent, etc.) regardless of weld materi
21、al thickness on all types of ferromagnetic and austenitic steels and alloys, as well as on cast irons. 2.5 inspection may be carried out on the original weld after construction, during operation, or after repair. 2.6 The following conditions can be found during MMM inspection: residual stress concen
22、tration zones caused by welding, and their distribution along the welded joint; zones of probable location of all types of micro- and macro-defects (pores, slag inclusions, discontinuities, cracks, ruptures). Defect classification by magnetic parameters is carried out following special testing techn
23、iques for a specific welded joint. BS ISO 24497-3:2007 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI 2 2.7 MMM inspection can be used for inspection of the following: the degree of quality degradation of weld
24、s by defects, and presence of developing defects; the quality of welded joints at time of certification, choice, and optimization of welding technology. 2.8 The MMM inspection temperature range is from 20 C to +60 , limited only by the conditions of the operators and inspection tools normal operatio
25、n. 2.9 Following MMM inspection, conventional non-destructive testing methods are applied in detected zones of maximal stress concentration and probable location of micro- and macro-defects. 3 Inspection conditions 3.1 Structures and components as inspection objects (IO) may be inspected using MMM b
26、oth while operating under load and after releasing the working load. 3.2 No special surface preparation is required. It is recommended to remove insulation. In individual cases non-magnetic insulation is allowed during inspection. The maximum permissible insulation layer thickness shall be determine
27、d experimentally. 3.3 The permissible range of material thickness is defined by the descriptions of the techniques for specific inspection applications. 3.4 The limiting factors for MMM application are the following: the presence of artificial material magnetization; the presence of a foreign ferrom
28、agnetic product near the IO; the presence of an external magnetic field or an electric welding current flow closer than 1 m to the IO. 3.5 Acoustic noise or mechanical vibrations close to and at the IO do not influence the inspection results. 4 Inspection devices 4.1 For inspection of equipment usin
29、g the MMM, specialized magnetometric devices are used. The standard procedure for the definition of stress concentration zones (SCZ) is described in the manual of the devices. 4.2 The principle of the operation of the specified devices is based on the registration of induced electrical voltage impul
30、ses in the flux-gate sensor coil, when this sensor is placed in the self-magnetic-leakage field (SMLF) in the near-surface area of the IO. Flux-gate sensors or other types, such as field meters or gradiometers, may be used as SMLF intensity measuring sensors. 4.3 The devices shall have a display for
31、 the graphic documentation of the used inspection parameters, a recording device with a microprocessor, a memory unit, and scanning devices realized by specialized sensors. The device shall be able to transfer the information to the computer, in order to produce inspection reports. The software for
32、the processing of computerized inspection results should be provided with the device. BS ISO 24497-3:2007 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI 3 4.4 The specialized sensors shall be provided with the
33、 device. The individual sensor type to use is defined by the MMM technique and the requirements of the IO. The sensor should have not less than two channels: the measuring channel and a channel for the registration of the Earths external magnetic field. With the sensors, an electronic module for the
34、 amplification of the measured field and a sensor for measuring the inspected scan path length shall be supplied. 4.5 The admissible error of magnetic field intensity measurements is defined in the description of the individual techniques depending on the IO. 4.6 The devices shall have the following
35、 metrological characteristics: The relative error of the measured magnetic field for each measurement channel should not exceed 5 %. The relative error of the measured scan path length should not exceed 5 %. The measurement range of the devices should be not less 1 000 A/m. The minimal scanning step
36、 (distance between two adjacent scanning points of the inspection) is 1 mm. The level of electronic noise caused by the processor and the microelectronic devices should not exceed 5 A/m. 4.7 The device shall have the possibility to define logfiles according to the user manual. 5 Inspection planning
37、5.1 Inspection planning includes the following basic stages: the analysis of the technical documentation of the object to be inspected and preparation of a checklist for the inspection; the adjustment and calibration of the devices and sensors, following the instructions given in the user manual; th
38、e selection of the individual sensors and the type of the inspection device; the segmentation of the IO into separate inspection areas and inspection units, according to the design features of the component and their documentation in an inspection logfile. 5.2 The technical documentation for the IO
39、shall include the following: a description of the steel grade; a description of the operation modes of the objects and failure modes; a description of the design features of the component and the locations of welded joints. BS ISO 24497-3:2007 Licensed Copy: London South Bank University, London Sout
40、h Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI 4 6 Inspection procedure 6.1 Inspection of welded joints using a device with a digital indication of the magnetic field intensity The sequence of scanning by the sensor of the device for the evaluation of several types
41、 of welded joints is shown in Figure 1. Dimensions in millimetres a) Moving the sensor along the welded joint b) Moving the sensor perpendicular to the welded joint Key 1, 2, 3 inspection zones WM weld material HAZ heat-affected zone of welded joint PM parent metal Figure 1 Scanning sequence by the
42、sensor for the evaluation of several types of welded joints according to the residual magnetization of the material The flux-gate sensor is placed perpendicular to the inspection surface and is moved by the operator manually and sequentially along the entire perimeter of a weld (separately along a w
43、eld material and along the heat-affected zones on both sides of the weld) and then perpendicular to the weld, with a distance from the edge of the weld of 30 mm to 50 mm on both sides of the parent material of a pipe. The second operator records the inspection data in a logbook: magnetic field inten
44、sity (Hp, A/m) with plus or minus amplitudes. The discontinuous change of the sign and value of the Hp field indicates the concentration of residual stresses along the Hp = 0 line for a specific segment of the welded joint. These segments have to be marked by chalk or paint. BS ISO 24497-3:2007 Lice
45、nsed Copy: London South Bank University, London South Bank University, Wed Jan 02 02:12:32 GMT+00:00 2008, Uncontrolled Copy, (c) BSI 5 6.2 Inspection of welded joints using a device having display, recorder, and scanner The inspection scheme for a butt-welded joint is shown in Figure 2. The inspect
46、ion is carried out using a scanner consisting of four flux-gate transducers 1, 2, 3, 4 and a length-measuring device, built into the case of a trolley programmed to measure the length of an inspected inspection segment simultaneously with the measurement of values of magnetic field intensity, Hp. As
47、 shown in Figure 2, during inspection, transducers 1 and 3 are arranged in the heat-affected zones from both sides of a weld, and the transducer 2 is centred between them. Before the beginning of the inspection for each measurement channel, the scanning step of measurement of the Hp field (value S i
48、n the set-up menu of the device) is set. The step of measurement is S or the distance between two adjacent scanning points of inspection, lK, for each measurement channel. This value should not exceed the wall thickness of the material joined by the weld. Key 1, 2, 3 flux-gate transducers of the sca
49、nner for the Hp field recording on a weld surface 4 flux-gate transducer for adjustment from an external magnetic field Hp 5 wheels of a drive of a length-meter lb base distance between adjacent transducers 1, 2, and 3 Figure 2 Inspection of butt-welded joints of pipes using a four-channel sensor of the device The base distance lb between adjacent transducers 1, 2, and 3 is set in accordance with the dimensions