GB/T 38980-2020 English PDF (GBT38980-2020)

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GB/T 38980-2020: Test method for artificial defect sizes of zirconium tube flaw detection comparison samples
GB/T 38980-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.99
H 21
Test Method for Artificial Defect Sizes of Zirconium
Tube Flaw Detection Comparison Samples
ISSUED ON: JULY 21, 2020
IMPLEMENTED ON: JUNE 1, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative References ... 4 
3 Principle ... 4 
4 Selection of Methods ... 5 
5 Replication Measurement Method ... 5 
6 Microscopic Measurement Method ... 5 
7 Data Processing ... 7 
8 Test Report ... 8 
Test Method for Artificial Defect Sizes of Zirconium
Tube Flaw Detection Comparison Samples
1 Scope
This Standard specifies the replication and microscopic measurement method of the
sizes of artificial defects (artificial grooves / through holes) of comparison specimens
for the flaw detection of zirconium tubes.
This Standard is applicable to the measurement of the sizes of artificial grooves /
through holes on the comparison specimens for the non-destructive testing of
zirconium tube ultrasound and eddy current, etc. The measurement of the sizes of
similar artificial defects on other metal comparison specimens may take this as a
reference.
2 Normative References
The following documents are indispensable to the application of this document. In
terms of references with a specified date, only versions with a specified date are
applicable to this document. In terms of references without a specified date, the latest
version (including all the modifications) is applicable to this document.
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and Judgement
of Limiting Values
YB/T 145 Die Casting and Size Measurement Method of Artificial Defects on the
Reference Sample Pipes
3 Principle
3.1 Replication Measurement Method
Replication measurement method is an indirection measurement method. By filling the
plastic material in the artificial defect and taking it out after solidification forming, the
three-dimensional appearance of the artificial defect is intuitively, vividly and
realistically reproduced. Take points, lines and sections; adopt measuring tools of
corresponding precisions to measure the length, width and depth of the artificial defect;
obtain the size data of the artificial defect.
3.2 Microscopic Measurement Method
a high magnification to focus on the specimen. Adjust the stage and the specimen, so
that the artificial defect is in the center of the field of view. Adjust the measurement
equipment, so that the plane of measurement can clearly focus; select the
measurement point.
6.3.1.4 The magnification for the measurement of the length and width of the artificial
groove is not lower than 100 ; the magnification for the measurement of the depth is
not lower than 200 ; the magnification for the measurement of the through hole is not
lower than 100 .
6.3.2 Measurement of artificial groove
6.3.2.1 Measurement of length and width: on the length or width boundary of the
artificial groove, determine the measurement point and perform the aiming reading. In
accordance with the relative displacement of the X or Y coordinates between the points
on the two boundaries in the length or width direction, calculate the length or width
value. The length measurement of transverse flaw shall be corrected in accordance
with the measured chord length.
6.3.2.2 Measurement of depth: on the surface and the bottom of the opening of the
artificial groove, respectively perform focus reading. In accordance with the relative
displacement of the Z coordinate during two focusing, calculate the depth value.
6.3.3 Measurement of through hole
On the circumference of the through hole, randomly choose three points. Through the
coordinates of the three points, calculate the diameter of the circle.
7 Data Processing
7.1 Replication Measurement Method
For the depth and width of each artificial defect, the maximum value of the cross-
sectional dissection measurement results taken from three points in the length
direction of the replication sample is taken as the measurement result; the length is
measured with a Vernier caliper. The measurement data shall be rounded off in
accordance with the stipulations of GB/T 8170.
7.2 Microscopic Measurement Method
For the measurement of the artificial grooves, the measurement of the sizes of each
artificial defect shall at least measure three points. The principle of point selection is:
respectively one point near the two ends and the middle position; repeat the
measurement for 3 times at each point and take the average value; the maximum value
of the three points is used as the measurement result. For the measurement of through
holes, each through hole shall be measured for 3 times on the circumference (the