SPECIFICATION FOR ULTRASONIC ANGLE-BEAM EXAMINATION OF STEEL PLATES
SA-577/SA-577M
iphone9(Identical with ASTM Specification A577/A577M-90.)
1.Scope
1.1This specification covers an ultrasonic angle-beam
procedure and acceptance standards for the detection of
internal discontinuities not laminar in nature and of
surface imperfections in a steel plate.This specification
is intended for u only as a supplement to specifications
which provide straight-beam ultrasonic examination.
NOTE—An internal discontinuity that is laminar in nature is one
who principal plane is parallel to the principal plane of the plate.
1.2Individuals performing examinations in accord-
ance with this specification shall be qualified and certi-
fied in accordance with the requirements of the latest
edition of ASNT SNT-TC-1A or an equivalent accepted
standard.An equivalent standard is one which covers
the qualification and certification of ultrasonic nonde-
structive examination candidates and which is acceptable
to the purchar.
1.3The values stated in either inch-pound units or
SI units are to be regarded parately as standard.
Within the text,the SI units are shown in brackets.The
values stated in each system are not exact equivalents;
therefore,each system must be ud independently of
the other.Combining values from the two systems may
result in nonconformance with the specification.
2.Referenced Document
2.1ASNT Standard:
SNT-TC-1A
1059
3.Ordering Information
3.1The inquiry and order shall indicate any additions
to the provisions of this specification as prescribed
in14.1.
4.Examination Conditions
4.1The examination shall be conducted in an area
free of operations that interfere with proper performance
of the examination.
4.2The surface of the plate shall be conditioned as
necessary to provide a clear,easily interpreted trace
pattern on the screen.Any specified identification which
is removed to achieve proper surface smoothness shall
be restored.
5.Apparatus
5.1The amplitude linearity shall be checked by
positioning the transducer over the depth resolution
notch in the IIW or similar block so that the signal
from the notch is approximately30%of the screen
height,and the signal from one of the back surfaces
祝义才is approximately60%of the screen height(two times
the height of the signal from the notch).A curve is不交叉
then plotted showing the deviations from the above
established2:1ratio that occurs as the amplitude of
the signal from the notch is raid in increments of
one scale division until the back reflection signal reaches
full scale,and then is lowered in increments of one
scale division until the notch signal reaches one scale
键盘排行榜division.At each increment the ratio of the two signals
is determined.The ratios are plotted on the graph at
rved
98
SA-577/SA-577M1998SECTION II
the position corresponding to the larger signal.Between
the limits of20%and80%of the screen height the ratio shall be within10%of2:1.Instrument ttings ud during inspection shall not cau variation outside
the10%limits established above.
5.2The arch unit shall be a45-deg(in steel) angle-beam type with active transducer length and width dimensions of a minimum of1⁄2in.[12.5mm]and a maximum of1in.[25mm].Search units of other sizes and angles may be ud for additional exploration and evaluation.
6.Examination Frequency
6.1The ultrasonic frequency lected for the examina-
tion shall be the highest frequency that permits detection
of the required calibration notch,such that the amplitude
of the indication yields a signal-to-noi ratio of at least3:1.
7.Calibration Reflector
幼儿园墙饰7.1A calibration notch,the geometry of which has been agreed upon by the purchar and the manufacturer, with a depth of3%of the plate thickness,shall be ud to calibrate the ultrasonic examination.The notch shall be at least1in.[25mm]long.
7.2Inrt the notch or notches on the surface of
the plate so that they are perpendicular to the long axis at a distance of2in.[50mm]or more from the short edge of the plate.Locate the notch not less than
2in.[50mm]from the long edges of the plate.
7.3When the notch cannot be inrted in the plate
to be tested,it may be placed in a calibration plate
of ultrasonically similar material.The calibration plate
will be considered ultrasonically similar if the height
of thefirst back reflection through it is within25%
of that through the plate to be tested at the same instrument calibration.The calibration plate thickness shall be within1in.[25mm]of the thickness of plates
to be tested,for plates of2in.[50mm]thickness and greater and within10%of plates who thickness is less than2in.[50mm].
7.4For plate thickness greater than2in.[50mm], inrt a cond calibration notch as described in7.2,
on the opposite side of the plate.
10608.Calibration Procedure
8.1Plate2in.[50mm]and Under in Thickness:
8.1.1Place the arch unit on the notched surface of the plate with the sound beam directed at the broad side of the notch and position to obtain maximum amplitude from thefirst vee-path indication which is clearly resolved from the initial pul.Adjust the instrument gain so that this reflection amplit
ude is at least50but not more than75%of full screen height. Record the location and amplitude of this indication on the screen.
八年级下册英语作文
8.1.2Move the arch unit away from the notch until the cond vee-path indication is obtained.Position the arch unit for maximum amplitude and record the indication amplitude.Draw a line between the peaks from the two successive notch indications on the screen. This line is the distance amplitude curve(DAC)for this material and shall be a100%reference line for reporting indication amplitudes.
8.2Plate Over2to6in.[50to150mm]Inclusive in Thickness:
8.2.1Place the arch unit on the test surface aimed at the broad side of the notch on the opposite surface of the plate.Position the arch unit to obtain a maximum one-half vee-path indication amplitude. Adjust the instrument gain so that this amplitude is at least50%but not more than80%of full screen height.Record the location and amplitude on the screen. Without adjusting the instrument ttings,repeat this procedure for the11⁄2vee-path indication.
8.2.2Without adjusting the instrument ttings, reposition the arch unit to obtain a maximum full vee-path indication from the notch on the test surface. Record the location and amplitude on the scre
en.
8.2.3Draw a line on the screen connecting the points established in8.2.1and8.2.2.This curve shall be a DAC for reporting indication amplitudes.
8.3Plate over6in.[150mm]in Thickness:
8.3.1Place the arch unit on the test surface aimed at the broad side of the notch on the opposite surface of the plate.Position the arch unit to obtain a maximum one-half vee-path indication amplitude. Adjust the instrument gain so that this amplitude is at least50%but not more than80%of full screen height. Record the location and amplitude on the screen.
8.3.2Without adjusting the instrument ttings, reposition the arch unit to obtain a maximum full
PART A—FERROUS MATERIAL SPECIFICATIONS SA-577/SA-577M
vee-path indication from the notch on the test surface. Record the location and amplitude on the screen.
8.3.3Draw a line on the screen connecting the points established in8.3.1and8.3.2.This line shall
be a DAC for reporting indication amplitudes.
9.Examination Procedure
基业长青读后感
9.1Scan one major surface of the plate on grid lines perpendicular and parallel to the major rolling direction. Grid lines shall be on9in.[225mm]centers.U a suitable couplant such as water,oil,or glycerin.Scan
by placing the arch unit near one edge with the ultrasonic beam directed toward the same edge and move the arch unit along the grid line in a direction perpendicular to the edge to a location two plate thickness beyond the plate center.Repeat this scanning procedure on all grid lines from each of the four edges.
9.2Measure grid lines from the center or one corner
of the plate.
9.3Position the arch unit to obtain a maximum indication amplitude from each obrved discontinuity.
9.4For each discontinuity indication that equals or exceeds the DAC,record the location and length,and
the amplitude to the nearest25%.No indication with
an amplitude less than the DAC shall be recorded.
9.5At each recorded discontinuity location,conduct
a100%examination of the mass under a9in.[225mm] square which has the recorded discontinuity position
at its center.Conduct the examination in directions perpendicular and parallel to the major rolling direction.
10.Acceptance Standard
10.1Any discontinuity indication that equals or ex-ceeds the DAC shall be considered unacceptable unless additional exploration by the longitudinal method indi-cates it is laminar in nature.
106111.Rehearing
11.1The manufacturer rerves the right to discuss unacceptable ultrasonically examined plate with the purchar with the object of possible repair of the ultrasonically indicated discontinuity before rejection of the plate.
12.Inspection
12.1The purchar’s reprentative shall have access, at all times while work on the contract of the purchar is being performed,to all parts of the manufacturer’s works that concern the ultrasonic examination of the material ordered.The manufacturer shall afford the reprentative all reasonable facilities to satisfy him that the material is being furnished in accordance with this specification.All examinations and verifications shall be so conducted as not to interfere unnecessarily with the manufacturer’s operations.
13.Marking
13.1Plates accepted in accordance with this specifi-cation shall be identified by metal stamping or stencilling “UT A577”in one corner of the plate,at a location within6in.[150mm]of the heat number.
14.Report
14.1Unless otherwi agreed upon between the pur-char and manufacturer,the manufacturer shall report the following data:
14.1.1Plate identity including pin-pointed re-cordable indication locations,lengths,and amplitudes.
14.1.2Examination parameters,including: couplant;arch unit type,angle,frequency,and size; instrument make,model,and rial number;and calibra-tion plate description.
14.1.3Date of examination and name of operator.
