BS M 39-1972 Method for penetrant inspection of aerospace materials and components《航空航天材料和部件穿透检验法》.pdf

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1、 BSI M*39 72 m Lb2Llbb 0097380 5 I UDC 629.7.018 : 620.179.111 h%. 39, February, 1972 BRITISH STAM)AItl3S INSTITUTION 2 FARK STREET, LONDON WlA 2BS INCORPOR The standard is not intended to be used as a level of acceptance or rejection as both of these aspects should be covered in an appropriate appl

2、ication stardard or be agreed between the interested parties, It is emphasized that non-destructive testing methods, being complementary to one another, should always be considered in relationship to testing as a whole. When non-destructive testing methods are specified, the most suitable method and

3、 amount of inspection -compatible with the ultimate application for the product should be e mp 1 oy ed , This standard makes reference to the following: British Standards: BS M.37. Method for the etch inspection of metallic BS 580. Trichloroethylene. BS 3683. GIossary of terms used in non-destruceiv

4、e testing. Part 1. Penetrant flaw detection. BS 4000. Sizes of paper and board. BS 4489. Method for assessing black Light used in material and components. non-des tructive testing. “Ministry of Defence Specifications: Defence Standard 03-2/1. Cleaning and preparation of metal surfaces. .DEF. 2331. P

5、rotective PX-1 dyed and.undyed. ARB-BL/10-9. Basic testing of materials of chemical solutions. Performance testing of pene- trant materials. Attention is also drawn to DTD.929“. Process specification. Penetrant methods of flaw detec- tion. *Obtainable from H.M.S.O. *Air Registration Board Circulars:

6、 BSI M*39 72 I Lb24bbel 0099383 7 m M. 39, February. 1972 METHOD 1. SCOPE This British Standard gives reqiiirements and procedures for detecting surface flaws in aero- space materials and components, during both the manufacturing stage and in service, by penetrant inspection techniques. 2. TERMS .4!

7、D DEFINIlONS For the purposes of this British Standard, the terms and definitions given in BS 3683, Part 1 apply 3. INTRODUCTION 3.1 General 3.1.1. Penetrant inspection techniques are capable of locating discontinuities such as laps, folds, cracks and porosity which are open to the surfacc of a mate

8、rial or component. Penetrant techniques can be used on materials independent of their physidal properties provided the surface is normally non-absorbent and compatible with the penetrant process. 3.1.2 The efficiency of the process is dependent upon the ability to carry out each separate operation c

9、orrectly. Inability to accomplish any single operation properly can seriously ffect the validity of the inspection. 3.1.3 The effectiveness of penetrant inspection rests on the technical competence of the personnel employed on the work and their ability to interpret indications given by the techniqu

10、es. In interpreting results, it is necessary to distin- guish between relevant indications from flaws and spurious indications arising from other causes. 3.1.4 The manufacturers of penetrant materials pr Ovide comprehen si ve technic al services and it is recommended that these services be used when

11、 selecting a process for a particular inspection task. Intermixing of materials from different manufacturers for an individual process is s trongly deprecated. 3.2 Principle of inspection. Penetrant inspection consists essentially of the following sequence of operations, see also Appendix A: (1) The

12、 surfaces of components to be inspected are prepared by pre-cleaning and degreasing. (2) Penetrant is applied to the prepared sur- faces and a period of time is allowed for it to enter any discontinuity open to the surfaces. (3) The excess penetrant is removed in such a manner that will ensure reten

13、tion of penetrant in any discontinuities. (4) A developer agent is applied in order to draw the penetrant liquid from the discontinuities out to the surface and thereby give an enhanced indication of the discontinuities. (5) The discontinuities are then visually examined and assessed under appropria

14、te viewing c ond it i on s, (6) The part is then cleaned and, as necessary, a corrosion preventative is applied. 4. COMPATIBILITY OF MATERIALS 4.1 All penetrant inspection materials shall be non-corrosive and Compatible with the material to be tested. 4.2 The chemical or physical properties of some

15、non-metallic materials may be adversely affected by pene.trant inspection materials. Therefore, their compatibility shall be established before testing components manufactured from such materials. 4.3 Special consideration shall be given to guided weapon and rocket components, as it is essential tha

16、t the penetrant inspection material be compatible with explosives, propellents or similar materials which may come into contact with the components after testing. 4.4 In situations where contamination might occur, care shall be taken to ensure that the penetrant inspection materials do not have a de

17、le terious effect on fuels, lubricants, hydraulic fluids, etc. 4.5 Unless a component has been thoroughly cleaned, a surface which has been treated with a dye peneirant shall not subsequently be processed using a fluorescent penetrant, since residual dye penetrant may react w.ith the fluorescent pen

18、etrant resulting in complete or partial quenching of fluorescence. 5. CLASSIFICATION AND GROUPING 5.1 Penetrants. For the purposes of this standard, penetrants are classified as either: A. fluorescent penetrants, or B. dye penetrants, according to whether the inspection of the surface under test is

19、to be carried out under black light or ordinary light. However, some penetrants may qualify for inclusion in both classes. 5.2 Penetrant removers, Penetrant removal opera- tions fall into five main classes i.e. those involving the use of: A. Solvent in liquid form. B. Solvent in vapour form. C. Wate

20、r only. D. Water before, and usually after, a proprietary penetrant remover solution which is usually water- soluble. 2 BSI M*39 72 I lb2ilbb9 8099382 i M. sgy February, i972 E. Emulsifier which is usually oil-soluble, C. Suspension of powder. in a comparatively involatile liquid carrier, oftenwater

21、-based. 5.4 Summary table. It is recommended that both A. Dry powder. manufacturers and users of penetrant materials B. Susperision of powder in a volatile liquid classify their systems in accordance with the followed by water. 5.3 Developers. Developers may consist of: carrier. . following: Penetra

22、nt Penetrant remover B. Solvent (vapour) C. Water D. Water (optional) Penetrant remover solution Water WatK E. Emulsifier - I 5.5 Grouping. Penetrant processes may, if required be grouped in terms of the above classification. Thus a sequence involving the use of a fluorescent penetrant, a water-wash

23、 and a dry powder developer can be placed .in a group designated ACA. It should not be inferred, how- ever, that all proprietary penetrant flaw detection processes belonging to one group are of necessity fully interchangeable or are of comparable sensi- tivity. 6. SAFETY PRECAUTIONS 6.1 As penetrant

24、 inspection techniques may require the use of toxic, flammable and volatile materiais, certain precautions have to be con- sidered. Working are as shall be we 11-ventil a ted and situated well away from heat, open fires and flames. 6.2 Care shall be taken to ensure that under no circumstances can un

25、filtered radiation from a black light source be directed at the eyes. The filter used with a black light source, either as an integral part f the lamp or as a separate com- ponent, shall always be maintained in good con- di tion. 6.3 Penetrant inspection materials and equipment shall be used with ca

26、ution and always in accor- dance with the manufacturers instructions. 7. SELECTION OF PROCESS 7.1 General. Some of the technical factors affect- ing the choice of a penetrant process are: (1) The surface conditions of the component, (2) The geometry of the component, (3) The contrast required and se

27、nsitivity i.e. the ability of a penetrant process to reveal a particular type of discontinuity in a given com- ponent. (4) Accessibility of component to be inspected, Dev :Oper A. Dry powder B. Suspensicn in volatile carrier C. Suspension in compasatively involatil: carrier 7.2 In situ applications.

28、 Penetrant processes shall only be applied in situ when the conditanc allow a satisfactory test to be carried out, Normally, the in situ application should be . . considered inferior to any controlled production ine application as, of necessity, the complete sequence of operations often has to be ap

29、plied manually under inferior lighting conditions and wih possibly restricted access. e items which require careful consideration in respect of ea in situ inspection procedure are as follows: 7.2.1 Preparation of surface. (1) It may be advantageous to carry out mask- ing for confinement of penetrant

30、 flaw detect& materials. (2) For the removal of protective finishes e.g. paint, an approved method should be used, (3) As the discontinuities being sought se- usually of crack formation, it may be advantageooo to apply a force which would tend to open any flaw. Such action shall not be taken, howeve

31、r,. without consulting the Design Authority. (4) When degreasing a component, considerable care is needed as any defect present might becop * filled with contaminant. In some instances, experience may show that it is impossible to clean defects adequately and resource to some other method of inspect

32、ion may be necessary. 7.2.2 Penetrant. ,The penetrant is applied by spray, brush, or in some cases, a reservoir can be constructed over the area requiring inspection. Contact times will often be longer than fic controlled production line application: 7.2.3 Remover. in general, a process involving a

33、solvent remover should be employed because of the obtiious difficulties of using water and the. associated drying process on large in situ com- ponents or structures. The remover should prefer- ably be applied with a lint-free cloth because if a spray is used the surface might be flooded to the _ BS

34、I MM39 72 R lib2Vbb9 0099383 O I M. 39, February, 1972 extent that.the remover could enter the defect and dilute the penetrant. Because of its toxic effects, there is a health hazard associated with spraying a solvent remover in confined spaces. 7.2.4 Developer. Better control of application can be

35、obtained if a wet developer appiied by spraying is used, particularly where access is restricted or the area being inspected is in a confined space. Care is needed to ensure that application of developer is not excessive as thick layers can mask small indications. 8. EQUIPMENT 8.1 Field inspection k

36、its. Field inspection kits for in situ applications comprise a complete set of processing materials, together with brushes, swabs, cleaning rags etc, and, if the fluorescent process is to be used, a black light lamp of suit- able intensity (see 12.1). 8.2 Equipment. This equipment comprises a series

37、 of individual units placed in a line sequence, enabling parts to be introduced at one end of the line and passed out at the other end. The units may be semi-automated or fully auto- mated and, as appropriate, the installation shall consist of the following in sequence: 8.2.1 Degrease/cooi station.

38、A trichloroethylene vapour tank, manufactured from suitable material, together with an area for cooling components prior to application of penetrant, shall be provided. Both shall be of adequate size to handle the flow of components . 8,2.2 Penetrant application station. The penetrant tank shall be

39、of suitable materials and of such a size that components can be satisfactorily covered with penetrant either by immersion or by a brush- ing or flow-on technique. The tank shall be equipped with a cover when not in use, and suit- able drains shall be provided for removal of both uncontaminated and c

40、ontaminated penetrant. 8,2.3 Penetrant drain station. The penetrant drain station shall consist of a sloping shallow tray arranged so that the penetrant is collected in a separate container. 8.2.4 Spray wash station. The spray wash station shall consist of a tank similar in size to the penetrant tan

41、k with an open drain in its base and with splash guards fitted to prevent water enter- ing adjacent tanks. For fluorescent penetrant inspection, the area should preferably contain a black light lamp for use under darkened condi- tions in order to facilitate obtaining the correct degree of washing. F

42、or washing purposes, an air- accelerated water spray in which the air-to-water ratio can be adjusted to produce a fine to medium spray is required. 8.2.5 Emulsifier station. The emulsifier tank shall 4 be of suitable material and size to enable the components to be completely immersed. 8.2.6 Agitate

43、d water wash station. The tank shall be of suitable material and size to enable total immersion of the components to be effected immediately it is required. The unit shall be fitted with a weir to enable water which is contaminated with penetrant to be removed. The water shall be continuously replen

44、ished and agitated. Agi tation may be achieved by air flow through drilled pipes arranged in the bottom of the tank or by me ch ani c al means. 8.2.7 Hot wash station. The tank shall be of suit- able material and size to enable total immersion of the component to be effected immediately it is requir

45、ed. The unit shall be fitted with a weir to enable water which is contaminated by penetrant to be renewed. Means shall be provided to control the temperature of the water within the range 65 to 85 T. 8.2.8 Drying stage. A supply of dry clean filtered air at a maximum pressure of 2 bar* (30 Ibf/in7 s

46、hall be available for the removal of excess water prior to drying. For drying purposes, a hot air circulating oven controlled in the temperature range of 60C to 85T is recommended. 8.2.9 Developing station. (1) Powder developer. Application is best achieved by using a dust storm cabinet, followed by

47、 extraction of excess powder from the cabinet, both sequences being in operation for a pre- determined time. The cabinet shall be of sufficient dimensions to accommodate the work in its entirev either as single components or multiples placed in wire mesh baskets. It shall have a sealed hinged lid an

48、d preferably be fitted with heaters to prevent contamination of the powder by moisture. The use of electrostatic spray or flock gun spray methods is not precluded. (2) Wet spray developer. The developer shall be applied using a suitable spray actuated with dry clean filtered air. The operation shoul

49、d be carried out in a cabinet which allows unrestricted spraying of the components to take place. An extraction system is required to remove excess spray. (3) Wet-dip developer. The developer shall be contained in a tank of suitable material and size to allow for complete immersion of the work piece and subsequent draining of excess developer from its surfaces. Mechanical means shall be provided to agitate the developer. 8.2.10 Inspection station (1) Fluorescent penetrant. The inspection station may consist of a booth or area with the level of ambient light