ASTM E2373 - 09

    Standard Practice for Use of the Ultrasonic Time of Flight Diffraction (TOFD) Technique

    Active Standard ASTM E2373 | Developed by Subcommittee: E07.06

    Book of Standards Volume: 03.03


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    Significance and Use

    This practice provides general principles for the application of the Time-of-Flight Diffraction Technique as a tool for detection and sizing of discontinuities.

    TOFD is a nondestructive ultrasonic examination technique that is not based on amplitude response. However, sufficient sensitivity is required to identify indications for evaluation.

    Techniques used are typically applied to welded joints in carbon steel but the principles may be applicable to other applications including other materials with suitable validation procedures agreeable to the contracting parties.

    In addition to a stand-alone ultrasonic detection technique TOFD may be used in conjunction with weld examinations such as those described in Practices E 164 and E 1961 where it may be used to improve sizing estimates of flaws detected by the manual or mechanized pulse-echo techniques and help discriminate between flaws and geometric reflectors.

    The technique has proven effective on thicknesses from 9 to 300 mm (0.375 to 12 in.). TOFD has been used on thicknesses outside of this range but special considerations are necessary. Techniques developed outside of this range of thickness shall be demonstrated as capable of meeting the required detection and sizing requirements of the specification used.

    1. Scope

    1.1 This practice establishes the requirements for developing ultrasonic examination procedures using the ultrasonic technique known as Time-of-Flight Diffraction (TOFD).

    1.2 Consistent with ASTM Policy, TOFD may be regarded as an ultrasonic test method whereby the qualities and characteristics of the item tested are evaluated, measured and in some cases identified. Measurements may be subject to precision and bias that may be determined statistically or as a function of some parameter(s) such as wavelength. This practice may be used for applications that would be qualitative and properly addressed as examinations as well as quantitative and more properly addressed as tests.

    1.3 The values stated in SI units are to be regarded as standard. Inch-pound units are provided for information.

    1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.


    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

    E164 Practice for Contact Ultrasonic Testing of Weldments

    E543 Specification for Agencies Performing Nondestructive Testing

    E1065 Guide for Evaluating Characteristics of Ultrasonic Search Units

    E1316 Terminology for Nondestructive Examinations

    E1324 Guide for Measuring Some Electronic Characteristics of Ultrasonic Testing Instruments

    ASNT Documents

    ANSI/ASNTCP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel

    Aerospace Industries Association Document

    NAS-410 Certification and Qualification of Nondestructive Testing Personnel

    Other Documents

    CodeCase2235 ASME Boiler and Pressure Vessel Code Available from the American Society of Mechanical Engineers, ASME International, 22 Law Drive, Box 2900, Fairfield, NJ 07007-2900.


    ICS Code

    ICS Number Code 71.040.99 (Other standards related to analytical chemistry)

    UNSPSC Code

    UNSPSC Code


    DOI: 10.1520/E2373-09

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