ASTM E1417/E1417M-21e1 Standard Practice for Liquid Penetrant Testing

Scope: 

ASTM E1417-21e1 establishes the basic parameters for conducting the liquid penetrant method that is used to detect surface cracks or pores. This procedure sets the fundamental guidelines for regulating the use of the liquid penetrant method. This procedure is written in such a way that it can be mentioned in an engineering drawing, a specification, or a contract. It must be reinforced by a thorough how-to procedure that complies with the demands of this practice because this ASTM technique is not a comprehensive how-to guide for the inspector to use. The information in Practice E165/E165M can be used to create specific requirements.

The in-process, final, and maintenance (in-service) examinations are all subject to the penetrant examination procedures outlined in this practice. These procedures can be used to find open or linked discontinuities, like absence of fusion, corrosion, cracks, laps, cold shuts, and porosity, on the surface of the component being examined.

When using components made of thermoplastic materials at high temperatures, caution must be used. Additionally, some cleansers, penetrants, and developers may harm nonmetallic objects like plastics. Testing should be done beforehand to make sure that the components being checked won’t be harmed by any cleaning or examination agents.

Standard Practice for Liquid Penetrant Testing

Classification

Penetrant examination processes and materials are classified according to the classification in AMS 2644. Penetrant systems covered are of the following types, methods, and sensitivity levels: 

Type
Type I: Fluorescent dye.
Type II: Visible dye.

Method
Method A: Water washable.
Method B: Post-emulsifiable, lipophilic.
Method C: Solvent-removable.
Method D: Post-emulsifiable, hydrophilic.

Sensitivity Levels
These levels apply to Type I penetrant systems only.

Sensitivity Level 1⁄2: Very low.
Sensitivity Level 1: Low.
Sensitivity Level 2: Medium.
Sensitivity Level 3: High.
Sensitivity Level 4: Ultrahigh.

Developers are classified as:
Form a: Dry powder.
Form b: Water-soluble.
Form c: Water-suspendable.
Form d: Nonaqueous for Type I fluorescent penetrant.
Form e: Nonaqueous for Type II visible dye.
Form f: Specific application.

Solvent removers are classified as:
Class 1: Halogenated.
Class 2: Non-Halogenated.
Class 3: Specific application.

Responsibility for Examination

The cognizant engineering organization is responsible for the conformance of examination requirements. It can also specify more stringent requirements than the minimum specified in this practice to ensure that a material meets its requirements. 

The supplier may use his own facilities to perform the examination requirements specified here. The purchaser can perform any examinations established in this practice to ensure that supplies conform to the requirements.

Specifying

Orders, contracts, or other appropriate documents specify the criteria by which the acceptability of components is to be evaluated. Engineering drawings or other applicable documents specify the acceptance criteria for the entire component. 

Personnel Qualification

Personnel performing examinations to this practice should be qualified and certified in accordance with ASNT Personnel Qualification SNT-TC-1A, ANSI/ASNT-CP-189 or NAS 410 for military purposes, or as specified in the contract or purchase order. 

Agency Qualification

The agency performing this practice may be evaluated in accordance with specification E543. 

Materials

Qualified Materials: Only materials listed on QPL-AMS-2644 should be used for penetrant testing. Materials that do not conform to the requirements of AMS 2644 may be used only if the cognizant engineering organization approves the material.  

Liquid Oxygen (LOX) Compatible Materials: Penetrant materials tested in accordance with Test Method D2512 and passing at 95 J or higher should be used on LOX wetted surfaces that cannot be thoroughly post-cleaned. These materials should be used in accordance with the material supplier instructions and require approval of the cognizant engineering organization when such materials do not meet the requirements of AMS 2644. 

Equipment and Facilities

1. Viewing Areas: 

For visible dye examination, Type II, the lighting system should provide at least 100 fc [1076 lx) of visible light when measured at the examination surface. 

For stationary fluorescent dye examination, Type I, the ambient visible light background should be less than 2 fc [21.5 lx] at the examination surface. The black lights should provide a minimum of 1000 µW/cm2 at the examination surface. 

For portable fluorescent dye examination, the viewing area should use dark canvas or other methods to reduce the visible light background to the lowest possible level during the examination.

Where lamps are physically too large to directly illuminate the examination surface, special lighting, such as UV pencil lights, or UV light guides should be used. 

2. Drying Oven:

If the components are dried by the oven, the dryer must be a forced-air recirculating type. In automated systems, where parts are dried by radiant heat and forced air, the travel speed of the system should be such as to prevent overdrying of parts. 

Written Procedures

Liquid penetrant examination procedures are similar for most components. A master written procedure is used that covers the details common to a variety of components. All written procedures should be approved by a qualified and certified individual. 

The following information is required in all written procedures: Details of the precleaning and etching process. Complete post-cleaning procedures. Classification of the penetrant examination materials. Complete processing parameters such as concentrations, application methods, dwell times, drying times, temperatures, and controls to prevent excessive drying of penetrant or overheating of components. 

Complete examination requirements including light intensities, the accept/reject criteria, and the method and location of marking. Identification of the components or areas within a component to be examined. 

Examination Sequence 

The penetrant examination should be performed after the completion of all operations that could cause discontinuities on the surface. Operations such as grinding, welding, straightening, machining, and heat treating. 

Surface Treatment:

The penetrant examination should be performed before treatments that can smear the surface but not by themselves cause surface discontinuities. Treatments such as vapor blasting, deburring, sanding, buffing, sandblasting, lapping, or peening. 

Surface Coatings:

All coatings such as paint, plating, corrosion should be removed before penetrant examination. The penetrant examination should be conducted before any surface finish, such as anodize.

Material and Process Limitations

Not all penetrant sensitivity levels, materials, and process methods are applicable to all examination requirements. The sensitivity level should be adequate for the intended purpose of the examination. Forms a and b (dry powder and water soluble) developers should not be used with Type II (visible dye) penetrant systems. 

Type II penetrant examination should not be used for the final acceptance examination of aerospace products. In addition, Type II penetrant examination should not be conducted before a Type I penetrant examination of the same surface.   

Records

Results of all final penetrant examinations should be recorded. All recorded results should be made available to the cognizant engineering organization upon request. The records shall include: identification of the procedure used, disposition of the examination; identification of the inspector’s examination stamp, electronic ID or signature; and the date of examination. Records should be kept for a minimum of three years or as otherwise specified in the purchase order or contract. 

Video 01: Liquid Penetrant Testing

Conclusion:

ASTM E1417-21e1 establishes the basic parameters for conducting the liquid penetrant method that is used to detect surface cracks or pores. This procedure sets the fundamental guidelines for regulating the use of the liquid penetrant method.