ASTM E215-98
(Practice)Standard Practice for Standardizing Equipment for Electromagnetic Examination of Seamless Aluminum-Alloy Tube
Standard Practice for Standardizing Equipment for Electromagnetic Examination of Seamless Aluminum-Alloy Tube
SCOPE
1.1 This practice is intended as a guide for standardizing eddy-current equipment employed in the examination of seamless aluminum-alloy tube. Artificial discontinuities consisting of flat-bottomed or through holes, or both, are employed as the means of standardizing the eddy-current system. General requirements for eddy-current testing procedures are included.
1.2 Procedures for fabrication of reference standards are given in Appendixes X1.1 and X1.2.
1.3 This practice is intended for the examination of tubular products having nominal diameters up to 4 in. (101.6 mm) and wall thicknesses up to the standard depth of penetration (SDP) of eddy currents for the particular alloy (conductivity) being examined and the test frequency being used. Note 1-This practice may also be used for larger diameters or heavier walls up to the effective depth of penetration (EDP) of eddy currents as specified by the using party or parties.
1.4 The values stated in inch-pound units are to be regarded as the standard.
1.5 This practice does not establish acceptance criteria. They must be established by the using party or parties.
1.6 This standard does not purport to address all of the safety problems, 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: E 215 – 98
Standard Practice for
Standardizing Equipment for Electromagnetic Examination
of Seamless Aluminum-Alloy Tube
This standard is issued under the fixed designation E 215; 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.
This specification has been approved for use by agencies of the Department of Defense.
1. Scope 2.2 Federal Standard:
2 Fed Std. No. 245D Tolerance for Aluminum Alloy and
1.1 This practice is intended as a guide for standardizing
Magnesium Alloy Wrought Products
eddy-current equipment employed in the examination of seam-
2.3 Other Documents:
less aluminum-alloy tube. Artificial discontinuities consisting
SNT-TC-1A Recommended Practice for Personnel Qualifi-
of flat-bottomed or through holes, or both, are employed as the
cation and Certification in Nondestructive Testing
means of standardizing the eddy-current system. General
ANSI/ASNT-CP-189 ASNT Standard for Qualification and
requirements for eddy-current testing procedures are included.
Certification of Nondestructive Testing Personnel
1.2 Procedures for fabrication of reference standards are
MIL-STD-410E Nondestructive Testing Personnel Qualifi-
given in Appendixes X1.1 and X1.2.
cation and Certification
1.3 This practice is intended for the examination of tubular
NAS-410 NAS Certification and Qualification of Nonde-
products having nominal diameters up to 4 in. (101.6 mm) and
structive Personnel (Quality Assurance Committee)
wall thicknesses up to the standard depth of penetration (SDP)
of eddy currents for the particular alloy (conductivity) being
3. Terminology
examined and the test frequency being used.
3.1 Standard terminology relating to electromagnetic ex-
NOTE 1—This practice may also be used for larger diameters or heavier
amination may be found in Terminology E 1316, Section C,
walls up to the effective depth of penetration (EDP) of eddy currents as
Electromagnetic Testing.
specified by the using party or parties.
4. Significance and Use
1.4 The values stated in inch-pound units are to be regarded
as the standard.
4.1 The test is performed by passing the tube lengthwise
1.5 This practice does not establish acceptance criteria.
through or near an eddy current sensor energized with alter-
They must be established by the using party or parties.
nating current of one or more frequencies. The electrical
1.6 This standard does not purport to address all of the
impedance of the eddy current sensor is modified by the
safety problems, if any, associated with its use. It is the
proximity of the tube. The extent of this modification is
responsibility of the user of this standard to establish appro-
determined by the distance between the eddy current sensor
priate safety and health practices and determine the applica-
and the tube, the dimensions, electrical conductivity, and
bility of regulatory limitations prior to use.
electrical conductivity of the tube. The presence of metallur-
gical or mechanical discontinuities in the tube will alter the
2. Referenced Documents
apparent impedance of the eddy current sensor. During passage
2.1 ASTM Standards:
of the tube, the changes in eddy current sensor characteristics
E 543 Practice for Agencies Performing Nondestructive
caused by localized differences in the tube produce electrical
Testing
signals which are amplified and modified to actuate either an
E 1316 Terminology for Nondestructive Examinations
audio or visual signalling device or a mechanical marker to
indicate the position of discontinuities in the tube length.
Signals can be produced by discontinuities located either on the
This practice is under the jurisdiction of ASTM Committee E-7 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.07 on
Electromagnetic Methods. Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Current edition approved Dec. 10, 1998. Published February 1999. Originally Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
e1 5
published as E 215 – 63. Last previous edition E 215 – 87(1992) . Available from American Society for Nondestructive Testing, 1711 Arlingate
For ASME Boiler and Pressure Vessel Code applications see related Practice Plaza, P.O. Box 28518, Columbus, OH 43228–0518.
SE-215 in the Code. Available from Aerospace Industries Association of America, Inc., 1250 Eye
Annual Book of ASTM Standards, Vol 03.03. Street, N.W., Washington, DC 20005.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E215–98
external or internal surface of the tube or by discontinuities the changes in the electromagnetic characteristics of the eddy
totally contained within the tube wall. current sensors. Equipment may include a detector, phase
4.2 The depth of penetration of eddy currents in the tube discriminator, filter circuits, gating circuits, and signalling
wall is influenced by the conductivity (alloy) of the material devices as required for the particular application.
being examined and the test frequency employed. As defined 6.2 Eddy Current Sensors—Eddy current sensors shall be
by the standard depth of penetration equation, the eddy-current capable of inducing currents in the tube and sensing changes in
penetration depth is inversely related to conductivity and test the electrical characteristics of the tube. The eddy current
frequency (Note 2). Beyond one standard depth of penetration sensors may be of the encircling coil (annular) type or surface
(SDP), the capacity to detect discontinuities by eddy currents is probe type.
reduced. Electromagnetic examination of seamless aluminum
alloy tube is most effective when the wall thickness does not 7. Standardization of Apparatus
exceed the SDP or in heavier tube walls when discontinuities
7.1 The apparatus shall be adjusted with an appropriate
of interest are within one SDP. The limit for detecting
reference standard to ensure that the equipment is operating at
metallurgical or mechanical discontinuities by way of conven-
the proper level of sensitivity, with the following consider-
tional eddy current sensors is generally accepted to be approxi-
ations:
mately three times the SDP point and is referred to as the
7.1.1 Primary reference standards employed for this pur-
effective depth of penetration (EDP).
pose shall be prepared in accordance with the methods de-
scribed in Appendix X1.1.
NOTE 2—The standard depth of penetration is defined by the following
equations: 7.1.2 Equivalent secondary reference standards, prepared in
accordance with methods described in Appendix X1.2, also
SDP 5 503.3
˛ may be employed for standardizing the apparatus.
fs
7.1.3 Reference standards normally are of the same alloy,
temper, and dimensions as the tube to be tested.
where:
7.1.4 Tests shall not be conducted unless the equipment can
SDP = one standard depth of penetration,
be set to the levels required by this standardization procedure.
f = frequency, Hz (cycles per second), and
7.1.5 For practical applications, reference standards also
s = conductivity, siemens-metre/mm .
may be employed to establish quality control levels.
or:
8. Procedure
8.1 Standardize the testing instrument using the appropriate
SDP 5 26
˛
fs
reference standard prior to testing and check at least every 4 h
during continuous operation, or whenever improper function-
ing of the testing apparatus is suspected. If improper function-
where:
ing occurs, restandardize the apparatus in accordance with
SDP = one standard depth of penetration, in
Section 7, and retest all tubes tested since the last successful
f = frequency in Hz (cycles per second), and
standardization.
s = conductivity, % IACS.
8.2 Tubes may be tested in the final drawn, annealed, or
5. Basis of Application
heat-treated temper, or in the drawn temper prior to the final
5.1 If specified in the contractual agreement, personnel
anneal or heat treatment.
performing examinations to this practice shall be qualified in
8.3 The length of tube over which end effect is significant
accordance with a nationally recognized NDT personnel quali-
may be determined by placing a series of holes or notches in
fication practice or standard such as ANSI/ASNT-CP-189,
special reference tubes and determining the distance from the
SNT-TC-1A, MIL-STD-410, NAS-410, ASNT-ACCP, or a
tube end at which the signal amplitude from the discontinuities
similar document and certified by the certifying agency’s as
begins to decrease.
applicable. The practice or standard used and its applicable
revision shall be identified in the contractual agreement be-
9. Application
tween the using parties.
9.1 This application covers the electromagnetic testing of
aluminum-alloy seamless tube using primary and secondary
NOTE 3—MIL-STD-410 is canceled and has been replaced with NAS-
410, however, it may be used with agreement between contracting parties.
reference standards.
9.2 Primary and secondary reference standards, described in
5.2 If specified in the contractual agreement, NDT agencies
Appendixes X1.1 and X1.2, respectively, when used as accep-
shall be qualified and evaluated in accordance with Practice
tance standards, will establish probable detection of defects
E 543. The applicable edition of Practice E 543 shall be
that are of a severity likely to cause leaks or substantial
specified in the contractual agreement.
weakening of the tube.
6. Apparatus
9.3 Using electronic apparatus and eddy current sensors
6.1 Electronic Apparatus—The electronic apparatus shall described in Section 6, the equipment sensitivity shall be
be capable of energizing eddy current sensors with alternating standardized in accordance with Section 7 under the following
currents of suitable frequencies and shall be capable of sensing test conditions:
E215–98
9.3.1 Frequency—The frequency shall be in the range from filtering of non-detrimental, time-varying discontinuities such
1 to 125 KHz. The test frequency should be adjusted to provide as geometry, pathline variation, high-frequency noise, etc.
optimum penetration of the tube wall or to place discontinuities 9.3.5 Sensitivity Setting—The sensitivity setting shall be
of interest within one SDP. Discontinuities located deeper than adjusted to provide clearly discernible indications of a conve-
the SDP point will be detected with less sensitivity. The SDP nient height for the appropriate accept holes (A or d ), but it
a
point will vary as a function of the tube alloy (conductivity) shall not be high enough to cause off-scale or saturated
and test frequency and may be determined by the depth of indications for the appropriate reject holes (2A or d )ofthe
b
penetration equation given in Section 4, Note 2. reference standard.
9.3.2 Speed of Inspection—The testing rate, or speed of the 9.3.6 Threshold-Level Setting—The threshold-level setting
tube with respect to the eddy current sensor, may vary with the (reject level) shall be adjusted to automatically trigger an audio
application. In encircling coil applications, inspection speeds or visual-signalling device or a mechanical marker when the
of 15.2 m/min (50 fpm) to 152 m/min (500 fpm) are recom- appropriate artificial discontinuity (or discontinuities) of the
mended where possible, but inspection speeds as high as 305 acceptance standard passes through or by the eddy current
m/min (1000 fpm) are permissible. In surface probe applica- sensor.
tions, inspection speeds are inherently slower due to reduced 9.4 When using reference standards as acceptance standards
surface coverage and the necessity to rotate the eddy current the threshold level should be adjusted to accept tubes exhibit-
sensor or the tube to produce a helical scan. All instrument ing eddy-current responses smaller than those obtained from
adjustments, that is, frequency, phase setting, filter setting, the appropriate reject holes (2A or d ) and to reject those with
b
sensitivity setting, threshold-level setting, etc., shall be made responses equivalent to or greater than those obtained from the
with the reference standard or acceptance standard or both appropriate reject holes (2A or d ) in the reference standard.
b
passing through or by the eddy current sensor at the same speed Experience shows that this procedure will aid in the rejection
at which the test of tube is to be conducted. of severe defects and, at the same time, minimize erroneous
9.3.3 Phase Setting—The phase setting should be selected rejection of tubes that might exhibit noise from non-
to provide the best signal-to-noise ratio for the reference detrimental discontinuities.
standard employed, that is, the maximum ratio of indication
10. Keywords
height from the appropriate artificial discontinuities to the
indication height from nondetrimental discontinuities. 10.1 aluminum alloy; eddy currents; electromagnetic test-
9.3.4 Filter Setting—The filter setting should be selected ing; equipment standardization; NDT; nondestructive testing;
commensurate with the testing speed to provide optimum tubing
APPENDIXES
(Nonmandatory Information)
X1. PURPOSE, DESCRIPTION, FABRICATION, AND CHECKING OF PRIMARY REFERENCE STANDARDS
X1.1 Purpose distance between adjacent holes is 152 mm (6 in.). The
minimum distance between a hole and either end of the tube
X1.1.1 Primary reference standards are used to standardize
shall be approximately 500 mm (20 in.).
testing equipment under operating conditions to establish
X1.2.3 Three of each of the reference standard holes A and
acceptable limits of sensitivity, reproducibility, and capability
for detecting defects of a severity likely to cause leaks or 2A shall be drilled consecutively to depths of one third and two
thirds the wall thickness, respectively in radial longitudinal
substantial weakening of the tube.
X1.1.2 The dimensions of the appropriate primary reference planes 120 6 5° apart.
standard are determined by the size of the tube to be tested. A
X1.2.4 The diameter, d, of the flat-bottomed drill used to
primary reference standard shall be a tube of the same alloy,
make a primary reference standard hole shall be determined
temper, outside diameter, D, and wall thickness, t, as the tube
mathematically with the following equation:
to be tested. This appendix covers the preparation of primary
2 3
d 5 k ~D/t! 3 10 (X1.1)
standards for test of seamless aluminum-alloy tube.
X1.2 Description
where:
X1.2.1 The primary reference standard shall contain six d = drill diameter of A and 2A flat-bottom holes, mm (in),
k = 7
...
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