Significance and Use
4.1 This practice is intended primarily for the examination of wrought metals, forged, rolled, machined parts or components to an ultrasonic class most typically specified in the purchase order or other contract document.
Scope
1.1 Purpose—This practice establishes the minimum requirements for ultrasonic examination of wrought products.
NOTE 1: This standard was adopted to replace MIL-STD-2154, 30 Sept. 1982. This standard is intended to be used for the same applications as the document which it replaced. Users should carefully review its requirements when considering its use for new, or different applications, or both.
1.2 Application—This practice is applicable for examination of materials such as, wrought metals and wrought metal products having a thickness or cross section equal to 0.250 in. (6.35 mm) or greater.
1.2.1 Wrought Aluminum Alloy Products—Examination shall be in accordance with Practice B594.
1.3 Acceptance Class—When examination is performed in accordance with this practice, engineering drawings, specifications, or other applicable documents shall indicate the acceptance criteria. Five ultrasonic acceptance classes are defined in Table 1. One or more of these classes may be used to establish the acceptance criteria or additional or alternate criteria may be specified.
(A) Any discontinuity with a response greater than the response from a flat-bottom hole or equivalent notch (see footnote B) at the estimated discontinuity depth and the discontinuity size given is not acceptable.
(B) See Fig. 3, Fig. 4, or Fig. 5 for dimensions of notches and holes when these are required for angle beam examination of tube walls and near-surface regions of cylindrical parts and other products.
(C) Multiple discontinuities with indications greater than the response from a reference flat-bottom hole or equivalent notch at the estimated discontinuity depth of the size given (diameter) are not acceptable if the centers of any two of these discontinuities are less than one inch apart (not applicable to Class C).
(D) Any discontinuity longer than the length given with indications equal to or greater than the response given (flat-bottom hole or notch response) is not acceptable. Not applicable to Class C).
(E) Loss of back reflection by more than 50 %, when compared to non-defective material in the same or a similar part, is not acceptable.
(F) For longitudinal examination of material over 6-in. (152.4-mm) thick in the short transverse direction, any loss of back reflection equal to or greater than 12 dB over an area 2 by 2 in. (50.8 by 50.8 mm) is rejectable. (Noise level is not relevant to this back reflection evaluation.
(G) Noise which exceeds the alarm level setting (see 7.4.10.7), is not acceptable, except for titanium. For titanium alloys, the alarm level may be set just above the noise level, but shall not exceed 70 % of the reference standard response.
(H) When examining titanium, Class AA and Class AAA, no rejection shall be made on the basis of “noise” level, if within the limits specified in footnote G.
(I) Evaluation may be done by setting up on a 3/64 in. (1.19 mm) hole and adding 7 dB of gain. (Also see Note 5 under Table 5.)
1.4 Order of Precedence—Contractual requirements and authorized direction from the cognizant engineering organization may add to or modify the requirements of this practice. Otherwise, in the event of conflict between the text of this practice and the references cited herein, the text of this practice takes precedence. Nothing in this practice, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.
1.5 Measurement Values—The values stated in inch-pounds are to be regarded as standard. The metric equivalents are in parentheses.
1.6 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.