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    ASTM E3166 - 20e1

    Standard Guide for Nondestructive Examination of Metal Additively Manufactured Aerospace Parts After Build

    Active Standard ASTM E3166 | Developed by Subcommittee: E07.10

    Book of Standards Volume: 03.04

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    Significance and Use

    4.1 Metal parts made by additive manufacturing differ from their traditional metal counterparts made by forging, casting, or welding. Additive manufacturing produces layers melted or sintered on top of each other. The part’s shape is controlled by a computer as well as by the layers. The computer directs energy from a laser or electron beam onto a powder bed or wire input material. These processing approaches have the potential of creating flaws that are undesirable in the as-built or finished part. In general, processing parameter anomalies and disruptions during a build may induce such “flaws.” Flaws can also be introduced because of contaminants present in the input material.

    4.2 Established NDT procedures such as those given in ASTM E07 standards are the basis for the NDT procedures discussed in this guide. These NDT procedures are used to inspect production parts before or after post-processing or finishing operations, or after receipt of finished parts by the end user prior to installation. The NDT procedures described in this guide are based on procedures developed for conventionally manufactured cast, wrought, or welded production parts.

    4.3 Application of the NDT procedures discussed in this guide is intended to reduce the likelihood of material or component failure, thus mitigating or eliminating the attendant risks associated with loss of function, and possibly, the loss of ground support personnel, crew, or mission.

    4.4 Input Materials—The input materials covered in this guide consist of, but are not limited to, ones made from aluminum alloys, titanium alloys, nickel-based alloys, cobalt-chromium alloys, and stainless steels. Input materials are either powders or wire.

    Note 3: When electron beams are used, the beam couples effectively with any electrically conductive material, including aluminum and copper-based alloys.

    4.4.1 Powders—High-quality powders required for AM process are produced by (1) plasma atomization, (2) inert gas atomization, or (3) centrifugal atomization using rotating electrodes (Fig. 1).

    (A) Abbreviations used: … = unknown or not applicable, CAD = computer aided design, CMM = coordinate measuring machine, CT = computed tomography, DED = directed energy deposition, EBM = electron beam melting, ET = eddy current testing, EMF = electromagnetic frequency, HIP = hot isostatic pressing, IRT = irfrared thermography, LOF = lack of fusion, MET = optical metrology, PA = plasma arc, PBF = powder bed fusion, PCRT = process compensated resonance testing, PT = penetrant testing, SLM = selective laser melting, and UT = ultrasonic testing.
    (B) Portions of table courtesy of AMAZE FP7 project.
    (C) Discontinuities or indications detected by NDT that are not necessarily rejectable.
    (D) Due to rapidly quenching, which may also lead to metastable or nonequilibrium morphologies.
    (E) Issue during long builds.
    (F) ISO TC 261 JG59 N 237 Guide.
    (G) If surface or near surface.

    Note 15: There are longstanding NDT standard flaw classes for welds and castings. In general, the defect classes for welded and cast parts differ from the flaw classes for AM parts.

    4.9 Process-Flaw Correlation—Given the range of materials and processes encountered in metal additive manufacturing, the process origins of flaws are still being characterized. However, examples exist. For example, when the energy input is insufficient, successive scan tracks do not properly fuse together and flaws appear along the scan line. In L-PBF parts, incomplete wetting and balling effects associated with insufficient energy input have been shown to lead to pores or voids. In addition, EB-PBF parts can show large voids or cavities extending across several layers when the process parameters are not carefully chosen. Smaller spherical pores can also develop in EBM parts due to entrapment of gases originally present gas-atomized metal powders.

    4.10 Flaw-Property Correlation—Parts with flaws, for example, porosity, LOF, skipped layers, stop/start flaws, inclusions, or excessive surface roughness, can exhibit degraded strength and fatigue properties compared with parts with fewer flaws. Furthermore, it is accepted practice to identify regions experiencing principle stresses before NDT is performed to assess the potential effect of any detected flaws in those regions. In addition to flaw type, size, and location, other flaw characteristics may be relevant, such as number, total volume, flaw/length (aspect ratio), orientation, and average nearest neighbor distance, and proximity to surfaces.

    (A) Abbreviations used: DED = Directed Energy Deposition, HAZ = Heat Affected Zone, HIP = Hot Isostatic Pressing
    (A) Abbreviations used: … = not applicable, AE = Acoustic Emission, CR = Computed Radiography, CT = Computed Tomography, DR = Digital Radiology, ET = Eddy Current Testing, IRT = Infrared Thermography, LT = Leak Testing , MET = Metrology, MT = Magnetic Particle Testing, NR = Neutron Radiography, PCRT = Process Compensated Resonance Testing, PT = Penetrant Testing, RT = Radiographic Testing, UT = Ultrasonic Testing, and VT = Visual Testing.
    (B) Includes Digital Imaging.
    (C) Especially helpful when characterizing internal passageways or cavities (complex geometry parts) for underfill and overfill, or other internal features not accessible to MET, PT, or VT (including borescopy).
    (D) Applicable if on surface.
    (E) Radiographic methods are not optimal for detecting tight laminar features like cracking and LOF, which typically do not exhibit enough density change.
    (F) If large enough to cause a leak or pressure drop across the part.
    (G) Macroscopic cracks only.
    (H) Conventional neutron radiography (NR) allows determination of internal and external dimensions.
    (I) Pycnometry (Archimedes principle).
    (J) Density variations will only show up in imaged regions having equivalent thickness.
    (K) If inclusions are large enough and sufficient scattering contrast exists.
    (L) Residual stress can be assessed if resulting from surface post-processing (for example, peening).

    1. Scope

    1.1 This guide discusses the use of established and emerging nondestructive testing (NDT) procedures used to inspect metal parts made by additive manufacturing (AM).

    1.2 The NDT procedures covered produce data related to and affected by microstructure, part geometry, part complexity, surface finish, and the different AM processes used.

    1.3 The parts tested by the procedures covered in this guide are used in aerospace applications; therefore, the inspection requirements for discontinuities and inspection points in general are different and more stringent than for materials and components used in non-aerospace applications.

    1.4 The metal materials under consideration include, but are not limited to, aluminum alloys, titanium alloys, nickel-based alloys, cobalt-chromium alloys, and stainless steels.

    1.5 The manufacturing processes considered use powder and wire feedstock, and laser or electron energy sources. Specific powder bed fusion (PBF) and directed energy deposition (DED) processes are discussed.

    1.6 This guide discusses NDT of parts after they have been fabricated. Parts will exist in one of three possible states: (1) raw, as-built parts before post-processing (heat treating, hot isostatic pressing, machining, etc.), (2) intermediately machined parts, or (3) finished parts after all post-processing is completed.

    1.7 The NDT procedures discussed in this guide are used by cognizant engineering organizations to detect both surface and volumetric flaws in as-built (raw) and post-processed (finished) parts.

    1.8 The NDT procedures discussed in this guide are computed tomography (CT, Section 7, including microfocus CT), eddy current testing (ET, Section 8), optical metrology (MET, Section 9), penetrant testing (PT, Section 10), process compensated resonance testing (PCRT, Section 11), radiographic testing (RT, Section 12), infrared thermography (IRT, Section 13), and ultrasonic testing (UT, Section 14). Other NDT procedures such as leak testing (LT) and magnetic particle testing (MT), which have known utility for inspection of AM parts, are not covered in this guide.

    1.9 Practices and guidance for in-process monitoring during the build, including guidance on sensor selection and in-process quality assurance, are not covered in this guide.

    1.10 This guide is based largely on established procedures under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of the appropriate subcommittee therein.

    1.11 This guide does not recommend a specific course of action for application of NDT to AM parts. It is intended to increase the awareness of established NDT procedures from the NDT perspective.

    1.12 Recommendations about the control of input materials, process equipment calibration, manufacturing processes, and post-processing are beyond the scope of this guide and are under the jurisdiction of ASTM Committee F42 on Additive Manufacturing Technologies. Standards under the jurisdiction of ASTM F42 or equivalent are followed whenever possible to ensure reproducible parts suitable for NDT are made.

    1.13 Recommendations about the inspection requirements and management of fracture critical AM parts are beyond the scope of this guide. Recommendations on fatigue, fracture mechanics, and fracture control are found in appropriate end user requirements documents, and in standards under the jurisdiction of ASTM Committee E08 on Fatigue and Fracture.

    Note 1: To determine the deformation and fatigue properties of metal parts made by additive manufacturing using destructive tests, consult Guide F3122.

    Note 2: To quantify the risks associated with fracture critical AM parts, it is incumbent upon the structural assessment community, such as ASTM Committee E08 on Fatigue and Fracture, to define critical initial flaw sizes (CIFS) for the part to define the objectives of the NDT.

    1.14 This guide does not specify accept-reject criteria used in procurement or as a means for approval of AM parts for service. Any accept-reject criteria are given solely for purposes of illustration and comparison.

    1.15 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

    1.16 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.17 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves

    E114 Practice for Ultrasonic Pulse-Echo Straight-Beam Contact Testing

    E215 Practice for Standardizing Equipment and Electromagnetic Examination of Seamless Aluminum-Alloy Tube

    E243 Practice for Electromagnetic (Eddy Current) Examination of Copper and Copper-Alloy Tubes

    E317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without the Use of Electronic Measurement Instruments

    E426 Practice for Electromagnetic (Eddy Current) Examination of Seamless and Welded Tubular Products, Titanium, Austenitic Stainless Steel and Similar Alloys

    E494 Practice for Measuring Ultrasonic Velocity in Materials

    E543 Specification for Agencies Performing Nondestructive Testing

    E571 Practice for Electromagnetic (Eddy-Current) Examination of Nickel and Nickel Alloy Tubular Products

    E587 Practice for Ultrasonic Angle-Beam Contact Testing

    E664/E664M Practice for the Measurement of the Apparent Attenuation of Longitudinal Ultrasonic Waves by Immersion Method

    E747 Practice for Design, Manufacture and Material Grouping Classification of Wire Image Quality Indicators (IQI) Used for Radiology

    E797/E797M Practice for Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact Method

    E1001 Practice for Detection and Evaluation of Discontinuities by the Immersed Pulse-Echo Ultrasonic Method Using Longitudinal Waves

    E1004 Test Method for Determining Electrical Conductivity Using the Electromagnetic (Eddy Current) Method

    E1025 Practice for Design, Manufacture, and Material Grouping Classification of Hole-Type Image Quality Indicators (IQI) Used for Radiography

    E1030 Practice for Radiographic Examination of Metallic Castings

    E1032 Practice for Radiographic Examination of Weldments Using Industrial X-Ray Film

    E1065 Practice for Evaluating Characteristics of Ultrasonic Search Units

    E1158 Guide for Material Selection and Fabrication of Reference Blocks for the Pulsed Longitudinal Wave Ultrasonic Testing of Metal and Metal Alloy Production Material

    E1209 Practice for Fluorescent Liquid Penetrant Testing Using the Water-Washable Process

    E1255 Practice for Radioscopy

    E1316 Terminology for Nondestructive Examinations

    E1416 Practice for Radioscopic Examination of Weldments

    E1417 Practice for Liquid Penetrant Testing

    E1441 Guide for Computed Tomography (CT)

    E1475 Guide for Data Fields for Computerized Transfer of Digital Radiological Examination Data

    E1570 Practice for Fan Beam Computed Tomographic (CT) Examination

    E1695 Test Method for Measurement of Computed Tomography (CT) System Performance

    E1742 Practice for Radiographic Examination

    E1817 Practice for Controlling Quality of Radiological Examination by Using Representative Quality Indicators (RQIs)

    E1901 Guide for Detection and Evaluation of Discontinuities by Contact Pulse-Echo Straight-Beam Ultrasonic Methods

    E1935 Test Method for Calibrating and Measuring CT Density

    E2001 Guide for Resonant Ultrasound Spectroscopy for Defect Detection in Both Metallic and Non-metallic Parts

    E2007 Guide for Computed Radiography

    E2033 Practice for Radiographic Examination Using Computed Radiography (Photostimulable Luminescence Method)

    E2104 Practice for Radiographic Examination of Advanced Aero and Turbine Materials and Components

    E2338 Practice for Characterization of Coatings Using Conformable Eddy Current Sensors without Coating Reference Standards

    E2339 Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE)

    E2373/E2373M Practice for Use of the Ultrasonic Time of Flight Diffraction (TOFD) Technique

    E2375 Practice for Ultrasonic Testing of Wrought Products

    E2445 Practice for Performance Evaluation and Long-Term Stability of Computed Radiography Systems

    E2446 Practice for Manufacturing Characterization of Computed Radiography Systems

    E2491 Guide for Evaluating Performance Characteristics of Phased-Array Ultrasonic Testing Instruments and Systems

    E2534 Practice for Process Compensated Resonance Testing Via Swept Sine Input for Metallic and Non-Metallic Parts

    E2597 Practice for Manufacturing Characterization of Digital Detector Arrays

    E2698 Practice for Radiographic Examination Using Digital Detector Arrays

    E2736 Guide for Digital Detector Array Radiography

    E2737 Practice for Digital Detector Array Performance Evaluation and Long-Term Stability

    E2767 Practice for Digital Imaging and Communication in Nondestructive Evaluation (DICONDE) for X-ray Computed Tomography (CT) Test Methods

    E2862 Practice for Probability of Detection Analysis for Hit/Miss Data

    E2884 Guide for Eddy Current Testing of Electrically Conducting Materials Using Conformable Sensor Arrays

    E2982 Guide for Nondestructive Testing of Thin-Walled Metallic Liners in Filament-Wound Pressure Vessels Used in Aerospace Applications

    E3022 Practice for Measurement of Emission Characteristics and Requirements for LED UV-A Lamps Used in Fluorescent Penetrant and Magnetic Particle Testing

    AIA Standard

    NAS 410 NAS Certification & Qualification of Nondestructive Test Personnel, Revision 4, 2014

    ASNT Standard and Practice

    ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel

    AWS Standard

    AWS D17.1 Specification for Fusion Welding of Aerospace Application

    Referencing This Standard
    Link Here
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    DOI: 10.1520/E3166-20E01

    Citation Format

    ASTM E3166-20e1, Standard Guide for Nondestructive Examination of Metal Additively Manufactured Aerospace Parts After Build, ASTM International, West Conshohocken, PA, 2020, www.astm.org

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