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1、 USSR STATE STANDARD NON-DESTRUCTIVE TESTING MAGNETIC PARTICLES METHOD GOST 21105-87 Official Edition GOSSTANDART OF RUSSIA Moscow Copyright Gosudarstvennye Standarty State Standard GOST (Russian) Provided by IHS under license with GOST .clxLicensee=IHS Employees/1111111001, User=Wing, Bernie Not fo
2、r Resale, 03/18/2007 20:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- UDC 620.179.141:006.354 Group T 59 USSR STATE STANDARD NON-DESTRUCTIVE TESTING Magnetic particles method All-Union Classification Code of Standards and Classifications (OKSTU) 0011 GOST 21105-87 D
3、ate of introduction 01.01.88 This Standard applies to magnetic particles method of non-destructive testing of parts, articles and semi-finished items made of ferromagnetic materials with a relative magnetic permeability of not less than 40 (hereinafter referred to as objects of testing). The terms u
4、sed in this Standard, and their definitions are in accordance with GOST 24450-80. Explanations of the terms used in this Standard are presented in Appendix 1. I. MAIN PROVISIONS 1.1. The magnetic particles method of non-destructive testing is based on the phenomena of attraction of particles of a ma
5、gnetic powder by magnetic leakage fluxes, arising above defects in magnetized objects of testing. Availability and length of indicator patterns caused by leakage fields of defects can be recorded either visually or by automatic devices used for image processing. 1.2. The magnetic particles method is
6、 designed for detection of surface and sub- surface continuity violations: hair-line cracks, cracks of different origin, lacks of penetration in welded joints, flakes, laps, surface ruptures, etc. 1.3. The magnetic particles method shall be used for testing objects made of ferromagnetic materials wi
7、th magnetic properties Official Edition * Standards Publishing House, 1987 Standards Publishing House, 1992 Revised edition with amendments This Standard may not be reproduced, in full or in part, reprinted or distributed without the permission of Gosstandart of Russia Copyright Gosudarstvennye Stan
8、darty State Standard GOST (Russian) Provided by IHS under license with GOST .clxLicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/18/2007 20:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- GOST 21105-87 p. 2 permitting to create in places of cont
9、inuity violation the magnetic leakage fields, sufficient for attraction of magnetic powder particles. The method may be used for testing the objects with non-magnetic coatings. 1.4. The sensitivity of the magnetic particles method shall be determined by magnetic characteristics of material of the ob
10、ject of testing (object under test), its shape, dimensions and surface roughness, strength of a magnetizing field, location and orientation of defects, mutual direction of a magnetizing field and a defect, properties of flaw detection material, method for applying it onto the object of testing, and
11、also by a way and conditions of recording the indicator pattern of the revealed defects. 1.5. Depending on dimensions of the detected defects there are established three reference levels of sensitivity, presented in table 1. T a b l e 1 Reference level of sensitivity Minimum width of opening of a co
12、nditional defect, Minimum length of a conditional defect, mm A B C 2.0 10.0 25.0 0.5 N o t e : 1. The reference level of sensitivity A is reached with the parameter of roughness of the surface under test Ra 2.5 , levels of sensitivity B and C - with Ra 10 . 2. If subsurface defects are detected, and
13、 also if Ra 10 , the sensitivity of the test method is reduced and the reference level of sensitivity is not normalized. 3. When testing the articles with non-magnetic coatings, the sensitivity of method gets decreased with the increase of the coating thickness. (Amended wording, Amendment No. 1). 1
14、.6. The type, location and orientation of intolerable flaws, and also the required level of sensitivity of testing the specific articles shall be established in the branch specifications and technical documentation for testing of articles. 1.7. The magnetic particles testing shall be carried out acc
15、ording to process sheets in compliance with GOST 3.1102-81 and GOST 3.1502-85, which contain the following data: the name of an article (unit), the name and number of a part, the sketch drawing of a part with indication of its overall dimensions, a testing zone, a testing method, the type and scheme
16、 of magnetization, the value of a magnetizing current or strength of the magnetic field, testing facilities (equipment, flaw detection materials), norms for rejection. Copyright Gosudarstvennye Standarty State Standard GOST (Russian) Provided by IHS under license with GOST .clxLicensee=IHS Employees
17、/1111111001, User=Wing, Bernie Not for Resale, 03/18/2007 20:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- p. 3 GOST 21105-87 2. REQUIREMENTS FOR EQUIPMENT 2.1. When carrying out tests by the magnetic particles method use shall be made of stationary, movable and por
18、table flaw detectors according to specifications and technical documentation. It is allowed to use specialized flaw detectors designed for testing the specific articles. 2.2. Depending on their purpose flaw detectors include the following functional units and devices: a power unit; an unit for forma
19、tion of magnetizing current; magnetizing devices; a demagnetizing device; a device for applying of flaw detection materials; an unit for automatic control of process test operations; actuating devices for implementation of automatic test operations; instruments and devices for controlling the qualit
20、y of flaw detection materials and technological processes; devices for inspection of the surface under test and for recording of defects. 2.3. Flaw detectors shall be equipped with magnetizing current meters. The error of measurements shall not exceed 10%. 2.4. Genera-purpose flaw detectors shall pr
21、ovide a capability of demagnetization of objects under test. 2.5. Flaw detectors, in which magnetization of articles is implemented by alternating, rectified or pulse currents, during testing by the method of residual magnetization shall provide the current cut-off at instant, when the value of resi
22、dual induction makes up not less than 0.9 of its peak value for the given material under the selected operating conditions. 2.6. When testing by a method of residual magnetization, it is not allowed to use both magnetizing devices in flaw detectors the direct-current electromagnets, and also other d
23、evices, in which lowering of a magnetic flux from the peak value down to zero during magnetization is performed for time interval, exceeding 5 ms. 2.7. The devices for inspection of the surface under test and for recording of defects shall include: ultra-violet (UV) radiation sources, optical device
24、s (magnifying glasses, binocular, stereoscopic microscopes; mirrors; endoscopes), as well as automatic systems of image processing. Copyright Gosudarstvennye Standarty State Standard GOST (Russian) Provided by IHS under license with GOST .clxLicensee=IHS Employees/1111111001, User=Wing, Bernie Not f
25、or Resale, 03/18/2007 20:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- GOST 21105-87 p. 4 2.8. The requirements for specialized flaw detectors shall be established in the industry specifications and technical documentation for testing the specific articles. 3. REQUI
26、REMENTS FOR FLAW DETECTION MATERIALS 3.1. With the magnetic particles testing method applied use shall be made of magnetic flaw detection materials: powders, suspensions and magnetic-rubberized paste. 3.2. Depending on condition of the surface under test (its color and roughness), magnetic propertie
27、s of material and required sensitivity of testing use shall be made of magnetic powders having a natural color, and also colored and luminescent powders. 3.3. Key properties of magnetic powders influencing on detection of defects are: dispersion, magnetic and optical characteristics. The quality of
28、magnetic powders shall be evaluated by methods, presented in the industry specifications and technical documentation for their delivery. 3.4. Properties of magnetic suspension influencing on detection of defects, shall be determined by composition, concentration and properties of its separate compon
29、ents. 3.4.1. The concentration of magnetic powder in suspension shall make up 25 g/l (5), and of luminescent powder 4 g/l (1). When testing threads and objects using magnetic fields with a strength 100 A/cm, the concentration of magnetic powder shall be reduced down to 5 g/l. Where technically justi
30、fied it is allowed to establish higher values of the concentration of magnetic powder in suspension. 3.4.2. The viscosity of disperse medium of suspension shall not exceed 3610-6 m2/s (36 cSt) at the temperature of testing. With the carrier viscosity higher than 10106 m2/s (10 cSt) the technical doc
31、umentation shall indicate the flowing-off time of the bulk of suspension, after which inspection of article is allowed. 3.4.3. The disperse medium of suspensions with luminescent magnetic powders shall not impair light and color properties of the powder, and its own luminescence shall not distort th
32、e test results. 3.5. Magnetic suspension shall not cause corrosion of the surface under test. 3.6. Magnetic rubberized paste presents a mix of magnetic powder and solidifying organic polymeric substances. Copyright Gosudarstvennye Standarty State Standard GOST (Russian) Provided by IHS under license
33、 with GOST .clxLicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/18/2007 20:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- p. 5 GOST 21105-87 3.7. The quality of finished flaw detection materials shall be determined prior to carrying-out of the
34、test on the standard specimens (samples) of enterprises certified in accordance with the established procedure. 4. PREPARATION AND TESTING PROCEDURE 4.1. The magnetic particles method of testing includes the following technological operations: preparation for testing; magnetization of object of test
35、ing; applying of flaw detection material onto the object under test; inspection of the surface under test and recording of indicator patterns of defects; evaluation of test results; demagnetization. 4.2. During magnetic particles testing the following methods are used: method of residual magnetizati
36、on (MRM); method of applied field (MAF). 4.2.1. When testing by the MRM method the object of testing shall be preliminarily magnetized, and then, after removal of a magnetizing field, flaw detection material shall be applied onto its surface. Time interval between the above- mentioned operations sha
37、ll be no more than one hour. Inspection of the surface under test shall be conducted after flowing-off of the bulk of suspension. The MRM method shall be used for testing the objects made of hard-magnetic materials with a coercive force of Hc 10 A/cm, and a residual induction of 0.5 T and more. 4.2.
38、2. When testing by the MAF method operations of magnetization of object under test and applying of suspension shall be carried out simultaneously. In this case, indicator patterns of the detected defects shall be formed in the course of magnetization. Magnetization shall be terminated after flowing-
39、off of the bulk of suspension from the surface under test. Inspection of the surface under test shall be performed upon termination of magnetization. To decrease heating of the object of testing it is recommended to use an intermittent mode of magnetization, at which current is conducted through a m
40、agnetizing device for 0.1 to 3 seconds with interruptions up to 5 seconds. 4.2.3. The selection of the testing method shall be implemented depending on magnetic properties of the object material and required sensitivity of testing in compliance with Appendix 2. 4.3. Preparation for test shall includ
41、e the following: preparation of the object for testing operations; checking the serviceability of flaw detectors; checking the quality of flaw detection materials. Copyright Gosudarstvennye Standarty State Standard GOST (Russian) Provided by IHS under license with GOST .clxLicensee=IHS Employees/111
42、1111001, User=Wing, Bernie Not for Resale, 03/18/2007 20:52:16 MDTNo reproduction or networking permitted without license from IHS -,-,- GOST 21105-87 p. 6 4.3.1. When preparing the volume it is necessary to remove from the surface under test corrosion products, remaining scale, oil contaminations,
43、and, if necessary, traces of paint-and-varnish coatings. 4.3.2. When testing the objects with a dark surface using a black magnetic powder one shall apply onto the surface under test a coating with a thickness of up to 20 ensuring the necessary contrast. 4.3.3. Checking of serviceability of flaw det
44、ectors and quality of flaw detection materials shall be carried out using standard specimens (samples) of enterprises manufactured specially or selected from the number of rejected articles with defects, whose dimensions conform to the taken level of sensitivity. The methods for manufacturing the sa
45、mples are presented in the recommended Appendix 3. 4.4. During magnetic particles testing use shall be made of the following types of magnetization: circular; longitudinal (pole); combined; in a rotating magnetic field. Types, methods and schemes of magnetization are given in table 2. 4.4.1. The typ
46、e and method of magnetization shall be selected depending on the dimensions and shape of the object, material and thickness of coating, and also on the nature and orientation of defects being subject to revealing. In so doing, the best condition for detection of defects - the perpendicular direction
47、 of the magnetizing field in relation to the direction of expected defects. If it is necessary to detect defects of different orientation use shall be made of magnetization in two or three mutually perpendicular directions, combined magnetization, and also magnetization in a rotating magnetic field.
48、 4.4.2. The strength of the magnetic field on the area of the object surface under test shall be selected depending on the required sensitivity of testing in compliance with the recommended Appendix 4. The values of magnetic field strength on the surface of object under test shall be determined with the aid of meters of magnetic field strength or with the help of field coils. 4.4.3. When testing the objects with a large demagnetization factor having a ratio of length to equivalent diameter less than 5, it is necessary to: form a chain of articles under test