Non-destructive testing - Penetrant inspection - General principles

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Non-destructive testing - Penetrant inspection - General principles

Essais non destruc tifs - Contr6le par ressuage - Principes ghn&aux

First edition - 1984-10-15

UDC 620.179.111 Ref. No. IS0 34524984 (E)

Descriptors inspection.

: tests, non-destructive tests, impregnating tests, classifications, macroscopic analysis, testing conditions, safety requirements,

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Foreword

IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Every member body interested in a subject for which a technical 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.

Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. They are approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting.

International Standard IS0 3452 was prepared by Technical Committee lSO/TC 135, Non-destructive testing.

It embodies the content of IS0 38794977 which is therefore withdrawn.

0 International Organization for Standardization, 1984

Printed in Switzerland

ii

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7.1

Application of

penetrant

...

7.2 Application of emulsifier. ...

7.3 Excess penetrant removal ...

7.4 Drying.. ...

7.5 Application of developer. ... .). ...

7.6 Development time ...

8 Viewing conditions ...

8.1 Fluorescent penetrants ...

8.2 Visible dye

penetrants

...

1

2

3

4

5

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8.3 Aidstoviewing ... 5

9 Inspection and interpretation. ... 5

9.1

Examination.. ... 5

9.2 Interpretation of results. ... 5

10

Furthertests ... 5

10.1

Retesting. ... 5

10.2 Subsequent testing ... 5

11

Cleaning after inspection ... 5

12 Sensitivity of tests. ... 5

13 Reporting of results ... 6

13.1 Presentation of data ... 6

13.2 Technique sheets ... 6

Annexes A

Specification sheet for a set of penetrant inspection materials ... 7

B

Penetrant inspection materials prescription form. ... 8

C Example of penetrant inspection technique sheet ... 9

iv

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General principles

1 Scope and field of application

1

.I This International Standard provides general guidance on methods of carrying out penetrant inspection on materials and components both during manufacture and in service, for example in situ inspection.

1.2

It does not deal with levels of acceptance or rejection, which should be the subject of separate International Stan- dards or of agreement between the parties concerned.

1.3 Penetrant inspection is used to locate discontinuities, such as laps, folds, cracks, porosity and fissures, which are open to the surface of a material or component.

Penetrant techniques can be used on materials irrespective of their physical properties, provided that the surface is normally non-absorbent and compatible with the penetrant process; see also 6.1.

1.4

For means of verification when carrying out penetrant inspection, reference should be made to IS0 3453.

NOTE - Definitions of terms used in this International Standard will be included in a future International Standard vocabulary of non- destructive testing.

2 References

IS0 3059, Non-destructive testing - Method for indirect assessment of ultra- violet radiation sources.

IS0 3453, Non-destructive testing - Penetrant inspection - Means of verification.

3 Principle

Penetrant inspection consists essentially of the following se- quence of operations :

a) Preparation of the surface of the material or component to be inspected by precleaning and degreasing.

b) Application of penetrant to the prepared surface and leaving for a period of time to allow the penetrant to enter any discontinuity open to that surface.

c) Removal of the excess penetrant in such a manner as to ensure retention of penetrant in any discontinuities.

d) Application of a developer in order to draw the penetrant from the discontinuity to the surface and thereby give an enhanced indication of the discontinuity.

e) Visual examination and assessment under appropriate viewing conditions.

f) Cleaning of the surface tested and, if necessary, application of a corrosion preventative.

It should be noted that testing at temperatures other than those specified for the materials may lead to erroneous results.

4 Safety precautions

4.1

As penetrant inspection techniques may require the use of toxic, flammable and volatile materials, the precautions prescribed and applicable to the use of all such materials shall be observed. Working areas shall be sufficiently ventilated and distant from heat sources, open fires and flames.

4.2

Care shall be taken to ensure that under no cir- cumstances can unfiltered radiation from an ultra-violet radiation source be directed at the eyes. The filter used with an ultra- violet radiation source, either as an integral part of the lamp or as a separate component, shall always be maintained in good condition. (Attention is drawn to IS0 3059.)

4.3

Penetrant inspection materials and equipment shall be used with caution and always in accordance with the instruc- tions provided by the manufacturer.

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ISO/DIS 3452

5 Classification of penetrant inspection materials

B : aqueous suspensions or solutions:

1 suspension of powder in water

5.1 General

² ^solution of powder in water

Penetrant inspection materials are formulated or selected according to the material or component to be tested and its surface condition, and according to the conditions under which the inspection is to be performed.

C: suspensions of powder in volatile, non-aqueous sol- vents, that are:

1 non-flammable 2 flammable

Sets of mutually compatible materials are constitued for par-

ticular purposes [called “systems” (see annex A)], each set

5.5 Classification of penetrant systems

comprising (either partially or fully)

-

_indicator _penetrant (penetrant),

For the purposes of this International Standard, penetrant systems are classified

-

excess penetrant remover (remover), -

-

_penetrant _developer (developer),

and characterized by data given in a prescription form (see annex B).

according to the method of inspection

A: fluorescent penetrant inspection B: visible dye penetrant inspection

c:

dual-purpose (fluorescent/visible dye) penetrant inspection

NOTES

1 The penetrant inspection materials constituting a set should not adversely affect the material or component to be tested.

-

_according to the type of penetrant (method of remov- ing excess penetrant):

2 Materials for preliminary cleaning of test surfaces are not con- sidered to be penetrant inspection materials.

1 water washable 2 post-emulsifiable

5.2 Penetrants

³ solvent removable.

For the purposes of this International Standard, penetrants are classif ied as :

A : fluorescent penetrants

B : visible dye penetrants

NOTES

1 It should not be inferred that all proprietary penetrant inspection materials of the same type and for one method are necessarily fully in- terchangeable or are of comparable sensitivity; intermixing of materials from various manufacturers is not recommended. Care should therefore be taken when selecting penetrant materials to ensure that they are compatible with each other and appropriate to the application.

C : dual-purpose (fluorescent/visible dye) penetrants

D : special purpose penetrants.

5.3 Excess penetrant removers

2 Fluorescent penetrant inspection should not be carried out after visible dye penetrant inspection unless the procedure has been previously qualified.

3 It is recommended that both manufacturers and users adopt the same classification system.

Penetrant removal operations fall into three main classes, i.e.

those involving the use of:

6 Test conditions

A: water only

6.1 Compatibility of materials

B : emulsifiers :

6.1.1

All penetrant inspection materials shall be compatible

1 oil-based emulsifiers with the material to be examined, particulary with regard to

2

water-based emulsifiers

long-term corrosion effects.

C:

solvent in liquid form.

6.1.2

For checking compatibility, it may be necessary to carry

out a special test, the nature of the test depending on the materials under examination.

5.4 Developers

Developers may be:

A: dry powders

6.1.3

In situations where contamination of fuels, lubricants, hydraulic fluids, etc., by penetrant inspection materials exer- ting deleterious effects might occur, great care shall be taken in the post-inspection cleaning operation. See also 11. I.

Non-destructive testing - Penetrant inspection - General principles