ASTM A939-96(2006)
(Test Method)Standard Test Method for Ultrasonic Examination from Bored Surfaces of Cylindrical Forgings
Standard Test Method for Ultrasonic Examination from Bored Surfaces of Cylindrical Forgings
SCOPE
1.1 This test method covers a basic procedure of ultrasonically inspecting cylindrical forgings with bores from the bore surface.
1.2 This test method applies to the manual testing mode. It does not restrict the use of other testing modes, such as mechanized or automated.
1.3 This test method applies to cylindrical forgings having bore sizes equal to or greater than 2.5 in. (63.5 mm).
1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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.
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Designation:A 939–96 (Reapproved 2006)
Standard Test Method for
Ultrasonic Examination from Bored Surfaces of Cylindrical
Forgings
This standard is issued under the fixed designation A 939; 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 3.2 The bore ultrasonic inspection shall be performed after
the final austenitizing and tempering heat treatment for me-
1.1 This test method covers a basic procedure of ultrasoni-
chanical properties of the forging, and may be performed either
cally inspecting cylindrical forgings with bores from the bore
prior to or after any subsequent stress relieving heat treatment.
surface.
3.3 The ultrasonic beam shall be introduced radially for
1.2 This test method applies to the manual testing mode. It
overall scanning.
does not restrict the use of other testing modes, such as
3.4 Forgings may be tested either when stationary or while
mechanized or automated.
rotated by means of a lathe or rollers.
1.3 This test method applies to cylindrical forgings having
3.5 To ensure complete coverage of the bore surface, the
bore sizes equal to or greater than 2.5 in. (63.5 mm).
search unit shall be indexed approximately 75 % of the
1.4 The values stated in inch-pound units are to be regarded
transducer width with each pass of the search unit.
as standard. The values given in parentheses are mathematical
3.6 Afrequency of 2 ⁄4 MHz shall be used unless additional
conversions to SI units that are provided for information only
transducer frequencies are specified by the purchaser.
and are not considered standard.
3.7 The bore hole diameter and calibration hole(s) shall be
1.5 This standard does not purport to address all of the
as specified on the purchaser’s drawing or order.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Pulsed Ultrasonic Reflection Equipment and
priate safety and health practices and determine the applica-
Accessories
bility of regulatory limitations prior to use.
4.1 Electronic Apparatus—Apulse echo instrument permit-
2. Significance and Use ting inspection frequencies of 1, 2.25, and 5 MHz is required.
The accuracy of discontinuity amplitude analysis usingthistest
2.1 This test method shall be used when ultrasonic inspec-
method involves a knowledge of the true operating frequency
tion from the bore surface is required by the order or
of the complete inspection system. One of the best ways to
specification for inspection purposes in which the acceptance
obtain the desired accuracy is by use of a tuned pulser and
of the forging is based on limitations of the number, amplitude,
narrow bans amplifier of known frequency response, with
or location of discontinuities or a combination thereof, which
either a broad band transducer or a narrow band tuned
leads to ultrasonic indications.
transducer of known and matching frequency. An equipment
2.2 The acceptance criteria shall be stated clearly as order
calibration plan that is acceptable to both the purchaser and the
requirements.
supplier shall be available.
2.3 This test method specifies dual search units, which
4.2 Amplifier—The amplifier and the cathode ray tube shall
depending on the angle, are sensitive only to 2 to 3 in. into the
provide linear response (within 65%)upto1 ⁄2 in. (38.1 mm)
metal from the bore surface.
sweeptopeak.Anequipmentcalibrationplanthatisacceptable
3. General Requirements
to both the purchaser and the supplier shall be available.
4.3 Signal Attenuator—The instrument shall contain a cali-
3.1 As far as possible, the entire bore surface shall be
brated gain control or signal attenuator (accurate within 65%
subjected to ultrasonic inspection. It may be impossible to
ineachcase)thatwillallowindicationsbeyondthelinearrange
inspect some small portions of the bore surface because of
of the instrum
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