ASTM E242-01(2010)

Standard Reference Radiographs for Appearances of Radiographic Images as Certain Parameters Are Changed

SIGNIFICANCE AND USE
A key consideration with any radiographic system is its capability to resolve detail (that is, sensitivity). The degree of obtainable sensitivity with a given system is dependent upon several radiographic parameters such as source energy level, film system, type and thickness of intensifying screens, and material thickness radiographed. These reference radiographs permit the user to estimate the degree of sensitivity change that may be obtained when these parameters are varied from a specific technique. This standard may also be used in conjunction with Test Method E1815 or with Test Method E746 to provide a basis for developing data for evaluation of a user's specific system. This data may assist a user in determining appropriate parameters for obtaining desired degrees of radiographic system sensitivity.
SCOPE
1.1 This document describes the appearance of a radiographic image where fundamental components of image quality are changed, that is, variables such as whether an X-ray or gamma ray source was used, the characteristics of the radiographic film and intensifying screens, and the geometrical configuration of the object under investigation as well as its associated radiographic set-up.
1.2 These reference radiographs consist of four composite illustrations and show how such factors as radiation energy, specimen thickness, and film properties affect the radiographic image. The reference radiograph films are an adjunct to this document and must be purchased separately from ASTM if needed.
1.3 The values stated in inch-pound units are to be regarded as the standard.
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.

General Information

• Status: Historical
• Publication Date: 31-May-2010
• ICS: 19.100 - Non-destructive testing
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.02 - Reference Radiological Images

Relations

• Replaces: ASTM E242-01(2005)e1 - Standard Reference Radiographs for Appearances of Radiographic Images as Certain Parameters Are Changed
• Effective Date: 01-Jun-2010
• Referred By: ASTM E1032-19 - Standard Practice for Radiographic Examination of Weldments Using Industrial X-Ray Film
• Effective Date: 01-Jun-2010

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E242 − 01(Reapproved 2010)
Standard Reference Radiographs for
Appearances of Radiographic Images as Certain Parameters
are Changed
This standard is issued under the fixed designation E242; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Industrial Radiography
2.2 ASTM Adjuncts:
1.1 This document describes the appearance of a radio-
Reference Radiographs for Appearances of Radiographic
graphic image where fundamental components of image qual-
Images as Certain Parameters Are Changed
ity are changed, that is, variables such as whether an X-ray or
gamma ray source was used, the characteristics of the radio-
3. Terminology
graphic film and intensifying screens, and the geometrical
3.1 Definitions: For definitions of terms used in this
configuration of the object under investigation as well as its
document, see Terminology E1316, Section D.
associated radiographic set-up.
1.2 These reference radiographs consist of four composite 4. Significance and Use
illustrations and show how such factors as radiation energy,
4.1 A key consideration with any radiographic system is its
specimen thickness, and film properties affect the radiographic
capability to resolve detail (that is, sensitivity). The degree of
image. The reference radiograph films are an adjunct to this
obtainable sensitivity with a given system is dependent upon
document and must be purchased separately from ASTM if
several radiographic parameters such as source energy level,
needed.
film system, type and thickness of intensifying screens, and
1.3 The values stated in inch-pound units are to be regarded material thickness radiographed. These reference radiographs
as the standard.
permit the user to estimate the degree of sensitivity change that
may be obtained when these parameters are varied from a
1.4 This standard does not purport to address all of the
specific technique. This standard may also be used in conjunc-
safety concerns, if any, associated with its use. It is the
tion with Test Method E1815 or with Test Method E746 to
responsibility of the user of this standard to establish appro-
provide a basis for developing data for evaluation of a user’s
priate safety and health practices and determine the applica-
specific system. This data may assist a user in determining
bility of regulatory limitations prior to use.
appropriate parameters for obtaining desired degrees of radio-
graphic system sensitivity.
2. Referenced Documents
2.1 ASTM Standards:
5. Factors Affecting Radiographic Appearance
E94 Guide for Radiographic Examination
5.1 The final interpretation of the radiograph is greatly
E746 Practice for Determining Relative Image Quality Re-
affected by the appearance of a discontinuity.Apoor technique
sponse of Industrial Radiographic Imaging Systems
can minimize the radiographic appearance of a discontinuity
E1316 Terminology for Nondestructive Examinations
and conversely the optimum technique can emphasize this
E1815 Test Method for Classification of Film Systems for
appearance.Theappearanceofaradiographicimageisaffected
mainly by:
5.1.1 X-ray or gamma ray energy.
These reference radiographs are under the jurisdiction of ASTM Committee
5.1.2 Section thickness,
E07 on Nondestructive Testing and is the direct responsibility of Subcommittee
E07.02 on Reference Radiological Images.
5.1.3 Unsharpness, and
Current edition approved June 1, 2010. Published November 2010. Originally
5.1.4 Film and screen combinations.
ε1
approved in 1964. Last previous edition approved in 2005 as E242 - 01 (2005) .
DOI: 10.1520/E0242-01R10.
5.2 The equation that considers most of the above factors is:
For ASME Boiler and Pressure Code applications see related Reference
∆x 5 c d 2 d /Gµ ~kx11! (1)
@ ~ ! #
Radiographs SE-242 in the Code. 1 2
Available from ASTM Headquarters. Order RRE0242.
4 where:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
∆x = thickness of discontinuity,
Standards volume information, refer to the standard’s Document Summary page on
c = constant,
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E242 − 01 (2010)
graphs which show signs of excessive wear and tear which
d −d = minimum density change perceptible by eye,
1 2
could influence the interpretation and use of the radiographs
G = film gradient,
should be replaced.
µ = linear absorption coefficient (effective),
k = scattering coefficient, and
7. Use of the Reference Radiographs
x = section thickness.
7.1 As radiation energy increases, the radiographic appear-
As the above equation shows, the minimum thickness of
ance of a given discontinuity becomes less distinct because of
detectable discontinuity (∆x) is:
the greater penetration of the radiation; that is, because of
5.2.1 A function of X-ray energy,
decreasing subject contrast.The reference radiographs permit a
5.2.2 A function of section thickness, and
comparison of the radiographic appearance of the weld, at
5.2.3 An inverse function of film gradient.
particular thickness over a range of X-ray or gamma ray
5.3 Although not clearly indicated by the above relation, the
energies.
size of detectable discontinuity is also a function of
7.2 Another condition that affects radiographic appearance
unsharpness, see Guide E94.
is the variation of thickness for a given X-ray or gamma ray
energy. As the thickness of examined material is increased, a
6. Radiographic Illustrations
discontinuity becomes less distinct in the radiographic image.
6.1 A series of 36 radiographs, each on 10-in. by 12-in.
This is due to two predominant factors:
[254-mm by 305-mm] film, were taken of a 12-in. by 12-in.
7.2.1 The X-ray or gamma ray beam divergence which
welded steel plate which contained discontinuities in the weld.
produces unsharpness on the film when traversing a large
These were taken to illustrate the differences in appearance of
thickness.
the radiographic image when techniques for taking radiographs
7.2.2 Scattered radiation within the material, which reduces
arevariedbychangingthefactorslistedinSection5.A2-in.by
the radiographic contrast.
2-in. [51-mm by 51-mm] area, which includes the identical
7.2.3 The above processes are a function of material thick-
image of the discontinuities in the weld, was selected and cut
ness and X-ray or gamma ray energy. This effect is illustrated
out from each 10-in. by 12-in.
...