DYE PENETRANT TESTING PROCEDURE
1. SCOPE: This Test method covers procedures for penetrant examination of butt and fillet weld with the associated Heat Affected Zone (HAZ) on the parent metal and components. All surface defects can be found by using this method.
2. PURPOSE: To lay down the system for Liquid penetration testing as a non-destructive test to find out defects.
3. RESPONSIBILITY: QAC head/ ASNT NDT level III person in company is responsible to control the system, and level I / trained worker is perform the Dye testing in front of QAC level II engineer. QAC engineer is responsible to execute the testing and documentation.
4. PERSONNEL QUALIFICATION: QAC engineer who witnessed the test should have minimum Valid ASNT level II in Dye penetrant testing .For procedure Qualification person should have ASNT level III.
5. EQUIPMENTS AND MATERIALS :
Penetrant
Developer
Cleaner/ Remover
Light source
Lint free clothes
6. CALIBRATION: Light meter (Lux meter) shall be calibrated at least once a year or whenever the meter has been repaired. If meter has not been in use for one year or more, calibration shall be done before being used.
7. METHODS TO BE USED
7.1. TECHNIQUE USED: Color contrast solvent removable (Visible) Dye penetrant with non-aqueous solvent suspended developer shall be used. (this is different for different companies as per company uses the method you can use this method into it)
7.2. SURFACE PREPARATION: Surface preparation by grinding or machining may be necessary where surface irregularities could mask indication due to discontinuities. Grit or Shot blasting is prohibited as a method of surface preparation. Surface preparation by grinding, machining or other methods may be necessary where surface irregularities could mask indication of unacceptable discontinuities.
7.3. SELECTION OF REAGENT CHEMICALS:
· The Quality Manager shall obtain certification of contaminant content for all liquid penetrant materials (cleaning agents, penetrants, solvents, developers, etc) batch wise by reagent manufacturer used on nickel base alloys, austenitic or duplex stainless steel and titanium. These certificates shall include the Manufacturer’s Batch No. and the test results obtained in accordance with mandatory appendix II of ASME Sec. V, Article 6.
· When examining nickel base alloys, all Penetrant materials shall be analyzed individually for sulfur content in accordance with SE 165. The sulfur contents shall not exceed 1% by weight.
· When examining austenitic or duplex stainless steel and titanium all Penetrant materials shall be analyzed individually for halogens contents in accordance with SE 165. The total halogen contents shall not exceed 1% by weight.
· Intermixing of penetrant material from different groups or from different Manufacturer, within a group is not permitted.
8. PROCESS:
8.1. PRE-CLEANING: Pre-cleaning of the surface to be examined & adjacent areas within 25 mm shall be done to make it free of rust, scales, welding flux, spatter, grease, paint, oily film, dirt, lint etc. The cleaning agents shall meet the above requirement, the cleaning shall be done by wiping with cleaner and lint free cloth.
8.2. DRYING AFTER CLEANING: This shall be done in order to avoid any liquid residue hindering the entrance of the penetrant in the discontinuity, which is accomplished by keeping the surface in ambient temperature for a minimum period of 1 minute.
8.3. PENETRANT APPLICATION: A) after the surface has been pre-cleaned, coat the surface thoroughly and uniformly with penetrant. The application of penetrant will be by spraying or brushing.
B) The temperature of penetrant and surface area of part to be examined shall be neither below 5°C nor above 52°C throughout the examination period including drying period after pre-cleaning.
8.4. DWELL TIME: The penetrant dwell time shall be for a minimum period of 10 minutes for the temperature range from 100 C to 520C.For temperatures from 50C to 100C minimum dwell time shall be 20 minutes. The area to be examined shall remain wet by the penetrant throughout the entire dwell time.
8.5. REMOVAL OF EXCESS PENETRATION: The excess penetrant, after the required dwell time is removed using a clean lint free material. The operation is repeated till the most traces of penetrant on the surface have been removed. Then a lint free material is moistened with solvent and the surface wiped until all remaining traces of penetrant are removed. To minimize removal of penetrant from discontinuities, care shall be taken to avoid the use of excess solvent. Flushing the surface with solvent, following the application of the penetrant and prior to developing is prohibited.
8.6. DRYING: The surface shall be allowed to dry by normal evaporation at room temperature. The application of developer shall be within 5 to 20 minutes after drying the surface. The Procedure needs to demonstrate above time interval. When examining long length of welds removal of excess penetrant shall be done in steps to ensure complying with the maximum time interval stated above.
8.7. APPLICATION OF NON AQUEOUS DEVELOPER:
8.7.1. Prior to applying the developer to the surface the developer must be thoroughly agitated to ensure adequate dispersion of suspended particles.
8.7.2. The developer shall be applied so that the coating thickness is sufficient enough to draw the penetrant out of discontinuities, but not too excessive which could cause the masking of indications.
8.7.3. With color contrast penetrant only a wet developer shall be used. The developer shall be applied by spraying to obtain a uniform thin coating over the surface. Drying shall be by normal evaporation. The surface is to be closely observed during the application of developer to monitor the behavior of indications which tends to bleed out profusely.
9. EXAMINATION: Final examination shall be made within 60 minutes after allowing the penetrant to bleed out for at least 10 min. after the wet developer coating is dry. The Examination shall be started as soon as the developer is dry and shall be done with minimum white light intensity of 100 fc (1000 lx) on the test surface to ensure adequate sensitivity during the examination and evaluation of indication. A 60 watt bulb incandescent at maximum 304 mm (12”) distance is demonstrated to provide above level of illumination.
9.1. EVALUATION OF INDICATION:
9.1.1. All indications shall be evaluated in accordance with the referencing code or Specification.
9.1.2. Relevant indications are those that result from mechanical discontinuities:
a) Linear indications are those indications in which the length is more than three times the width.
b) Rounded indication or indications which are circular or elliptical with lengths less than three times the width.
c) Any questionable or doubtful indications shall be re-tested to verify whether or not actual defects are present.
10.POST CLEANING:
· Examination cleaning shall be carried out as soon as practical after completion of the examination using a process that does not adversely affect the part.
· Post cleaning is carried out using cleaner in order to remove residual penetrant and developer that will interfere with subsequent processing.
11.ACCEPTANCE CRITERIA:
Acceptance criteria for specific Codes are listed as below.
These acceptance standards shall apply unless other more
Restrictive standards are specified if required by client. ANSI / ASME, B 31.1 & ANSI / ASME B 31.3
Indication > 1.5 mm shall be considered as relevant
1. Linear Indication: Any crack or linear indication
2. Rounded Indications with dimensions >5.0 mm, Four or more rounded indication in a line separated by 1.5 mm or less edge to edge.
ASME SEC VIII D1
Indications > 1.5 mm shall be considered as relevant The
following indications shall be rejectable:
1. Relevant linear indication > 1.5 mm
2. Relevant rounded indications > 5 mm
3. Four or more rounded indications in a line separated by 1.5 mm or less (edge to edge).
AWS D1.1
Acceptance / Rejection criteria is dependent on service condition.
ASME Sec IX
Indications > 1.5 mm shall be considered as relevant The
following indications shall be rejectable:
1. Relevant linear indication >1.5 mm
2. Relevant rounded indications > 5 mm
3. Four or more rounded indications in a line separated by 1.5 mm or less (edge to edge).
ASME Sec I
Indications > 1.5 mm shall be considered as relevant The
following indications shall be rejectable:
1.Relevant linear indication >1.5 mm
2. Relevant rounded indications > 5 mm
3. Four or more rounded indications in a line separated by
1.5 mm or less (edge to edge).
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