ASTM E746-93(1998)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: E 746 – 93 (Reapproved 1998) An American National Standard
Standard Test Method for
Determining Relative Image Quality Response of Industrial
Radiographic Film
This standard is issued under the fixed designation E 746; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Fig. 1. The IQI steps may be fabricated separately and taped
together to form the penetrameter array as shown. The tape
1.1 This test method covers the determination of the relative
shall not cover any of the holes in the IQI.
image quality response of industrial radiographic film when
3.1.2 The absorber plate shall be made of mild steel. It shall
exposed to 200-kV X rays. The evaluation of the film is based
be at least 200 by 250 mm (8 by 10 in.) and 19 6 0.12 mm
upon the threshold visibility of penetrameter holes in a special
(0.7506 0.005 in.) thick. The surface finish of the absorber
image quality indicator (IQI). Results for a given film type may
plate shall be a maximum of 6.3 μm (250 μin.) R , ground
a
vary, depending upon the particular development system used.
finish (both faces).
It is, therefore, necessary to state the development system and
geometric conditions used in this determination. By holding
4. Calibration of X-Ray Source
the technique parameters (except exposure time) and process-
4.1 The voltage calibration of the X-ray source is based on
ing parameters constant, the image quality response of radio-
ANSI PH2.8. With an 8-mm (0.32-in.) copper filter at the
graphic film may be evaluated on a relative basis.
X-ray tube and a target to detector distance of at least 750 mm
1.2 Alternately this test method may be used for determi-
(29.5 in.), adjust the kilovoltage until the half value layer in
nation of the relative image quality response of a radiographic
copper is 3.5 mm (0.14 in.) (see Specification B 152). Make a
film when exposed to 200-KV X-rays as any other single
reading of the detector with 8 mm of copper at the tube, and
component of the system (such as screens) is varied.
then make a second reading with a total of 11.5 mm (0.45 in.)
1.3 This standard does not purport to address all of the
at the tube.
safety concerns, if any, associated with its use. It is the
4.2 Calculate the ratio of the two readings. If this ratio is not
responsibility of the user of this standard to establish appro-
2, adjust the kilovoltage up or down and repeat the measure-
priate safety and health practices and determine the applica-
ment until a ratio of 2 (within 5 %) is obtained. Record the
bility of regulatory limitations prior to use.
machine settings and use for the film tests. During tests,
2. Referenced Documents remove the 8 mm (0.32 in.) and 3.5 mm (0.14 in.) of copper.
2.1 ASTM Standards:
5. Film Holder and Screens
B 152 Specification for Copper Sheet, Strip, Plate, and
5.1 Enclose a single film in a cassette with low absorption.
Rolled Bar
The cassette shall provide a means for ensuring good film-
2.2 ANSI Standard:
screen contact.
ANSI PH2.8 Sensitometry of Industrial X-ray Films for
3 5.2 Place the film between lead-foil screens, the front screen
Energies up to 3 Million Electron Volts
being 0.130 6 0.013 mm (0.005 6 0.0005 in.) thick and the
3. Test Specimen back screen 0.250 6 0.025 mm (0.010 6 0.001 in.) thick.
3.1 The test specimen shall consist of a special image
NOTE 1—These thicknesses reflect commercially available tolerances
quality indicator (IQI) placed on the tube side of a 19-mm in lead foil for use as radiographic screens.
( ⁄4-in.) steel plate.
5.3 When the component to be evaluated is a screen or
3.1.1 The special image quality indicator (IQI) shall be
screen system, other than lead screen as specified in 5.2, place
fabricated from mild steel. The dimensions shall conform to
the film in the proper position with the screen or screen system.
1 1
5.4 Use a 6.3 6 0.8 mm ( ⁄4 6 ⁄32 in.) thick lead “backup”
1 behind the cassette. The backup lead shall extend at least 25
This test method is under the jurisdiction of ASTM Committee E-7 on
Nondestructive Testing and is the direct responsibility of Subcommittee E07.01 on mm (1 in.) beyond each edge of the cassette.
Radiographic Practice and Penetrameters.
Current edition approved Sept. 15, 1993. Published November 1993. Originally
6. Procedure
published as E 746 – 80. Last previous edition E 746 – 87 (1992).
6.1 The sources to film distance is based upon achieving a
Annual Book of ASTM Standards, Vol 02.01.
Available from American National Standards Institute, 11 West 42nd Street, geometrical unsharpness (Ug) of 0.05 mm (0.002 in.) or less on
13th Floor, New York, NY 10036.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 746
Step Identification Shim Thickness, mm (in.) Hole Identification Hole Size, mm (in.)
15 0.38 6 0.012 (0.015 6 0.0005) 32 0.81 6 0.025 (0.0326 0.001)
10 0.25 6 0.012 (0.010 6 0.0005) 31 0.79 6 0.025 (0.031 6 0.001)
8 0.20 6 0.012 (0.008 6 0.0005) 28 0.71 6 0.025 (0.0286 0.001)
5 0.13 6 0.012 (0.005 6 0.0005) 25 0.64 6 0.025 (0.025 6 0.001)
23 0.58 6 0.025 (0.0236 0.001)
20 0.50 6 0.025 (0.020 6 0.001)
Hole Spacing (horizontal): 5 6 0.1 mm (0.2 6 0.004 in.) Nonaccumulative
Row Spacing: 3 6 0.1 mm (0.2 6 0.004 in.)
Spacing between hole sets: 5 6 0.1 mm (0.2 6 0.004 in.)
All other dimensions shall be in accordance with standard engineering practice.
FIG. 1 Image Quality Indicator
a 19-mm ( ⁄4-in.) thick absorber plate. Calculate the minimum 6.3.3 Identify the film number, type, exposure, and other
source to film distance, D, in millimetres, as follows: technique data by means of lead letters, or numerals, placed in
the upper righthand corner of the steel plate. Do not place so as
D 5 381 f
to interfere with the image of the holes in the IQI. Make these
where: identification symbols as small and unobtrusive as possible.
D 5 source to film distance, mm, and
Record this identification number on the data sheet for this
f5 ffocal spot size, mm.
exposure (see Section 7).
The distance shall be not less than 1 m (39.4 in.).
6.3.4 In order to minimize any effects caused by latent
6.2 See the physical set up as shown in Fig. 2. Position the
image instability, process the exposed film not more than 8 h
X-ray tube directly over the center of the test specimen and
after exposure.
film. The plane of the film and test specimen must be normal
6.4 Processing—The image quality response of the film
to the central
...