GB/T 37930-2019 English PDF (GBT37930-2019)

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GB/T 37930-2019: Non-destructive testing instruments -- Technical specifications of X-ray real-time imaging system for automobile wheel
GB/T 37930-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 19.100
N 78
Non-destructive Testing Instruments - Technical
Specifications of X-ray Real-time Imaging System for
Automobile Wheel
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: MARCH 1, 2020
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 Terms and Definitions ... 4 
4 Testing Personnel ... 8 
5 X-ray Real-time Imaging Testing System ... 8 
6 Imaging Technology ... 10 
7 Image Quality ... 14 
8 Image Display and Observation ... 16 
9 Image Evaluation ... 17 
10 Test Report ... 17 
11 Image Storage ... 17 
12 Process Evaluation ... 18 
Appendix A (Normative) Standard Image Grayscale Test Paper ... 20 
Appendix B (Normative) Testing Methods for Resolution and Image
Unsharpness ... 21 
Appendix C (Normative) Process Evaluation ... 24 
Non-destructive Testing Instruments - Technical
Specifications of X-ray Real-time Imaging System for
Automobile Wheel
1 Scope
This Standard stipulates the system composition, X-ray detector, testing environment,
testing technology, imaging technology, image quality, image display and observation,
image evaluation, test report, image storage and process evaluation of X-ray real-time
imaging testing instrument for automobile wheel.
This Standard is applicable to X-ray real-time imaging testing instrument for automobile
wheel.
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 18871 Basic Standards for Protection against Ionizing Radiation and for the Safety
of Radiation Sources;
GB/T 23903 Resolution Indicators for Ray Image;
JB/T 4730.2-2016 Non-destructive Testing of Pressure Equipment - Part 2:
Radiographic Testing;
JB/T 7902 Non-destructive Testing - Specification for Wire-type Image Quality
Indicators;
ASTM E155 Reference Radiographs for Inspection of Aluminum and Magnesium
Castings
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 X-ray Digital Radioscopy
X-ray digital radioscopy refers to an imaging method, which adopts photoelectric
Flat panel detector refers to an X-ray detector which receives and converts into image
data output through flat panel two-dimensional image detector array after X-ray is
converted into optical (electric) signal through a conversion screen.
3.8 Linear Diode Array; LDA
Linear diode array refers to an X-ray detector which receives and converts into digital
signals through linear array image sensor after X-ray is converted into optical (electric)
signal through a conversion screen.
NOTE: linear diode array needs to utilize the relative motion with objects to form a digital
image of the testing zone.
3.9 Image Intensifier Tube; IIT
Image intensifier tube refers to a device which utilizes the method of photoelectric
multiple to obtain high-brightness visible light image on the output screen after X-ray
is converted into visible light through a scintillator.
NOTE: generally speaking, it couples with CCD (charge coupled device) or CMOS
(complementary metal oxide semiconductor), then, outputs video electrical signals
or direct digital signals.
3.10 Sensitivity
Sensitivity refers to the minimum diameter of image quality indicator that is visible to
the naked eyes in the displayed perspective image.
NOTE: it shall be expressed in image quality indicators.
3.11 Dynamic Range
Dynamic range refers to the ratio of the maximum value that a detector can output to
the dark field signal standard deviation under the condition of conducting no calibration.
3.12 Pixel
Pixel refers to the minimum constitutional unit of digital image and the minimum
geometric dimension that can be identified in display image.
NOTE: different grayscale values of various pixels constitute different brightness of digital
image.
3.13 Line Pair
Line pair is constituted of a line and a spacing, and the width of the spacing equals to
the width of the line.
NOTE: the number of identifiable line pairs within the range of each millimeter of width is
NOTE: signal to noise ratio is used to evaluate digital image’s noise amplitude; it is a
decisive influencing factor in sensitivity testing.
4 Testing Personnel
Personnel engaged in X-ray digital imaging testing shall obtain non-destructive testing
qualification of corresponding items and grades, then, they may be allowed in
corresponding work.
Testing personnel shall possess knowledge related with the testing technology and
grasp corresponding basic computer operating methods.
Testing personnel shall be able to identify 25 pieces of full data on the image in
Appendix A from a digital imaging system display within 1 min.
5 X-ray Real-time Imaging Testing System
5.1 System Composition
X-ray real-time imaging system is mainly constituted of X-ray machine, X-ray detector,
computer image processing system, mechanical transmission system and testing
equipment and tooling, etc.
5.2 X-ray Machine
In accordance with the thickness and texture of the tested part of automobile wheel,
and the focal length, select X-ray machine’s energy range. The dimension of X-ray
tube focus shall be not more than 3.0 mm.
5.3 X-ray Detector
In accordance with different testing requirements and testing conditions, the following
X-ray detectors may be selected:
---Flat panel detector;
---Linear diode array detector;
---Image intensifier tube;
---Other detectors that have similar functions as mentioned above.
5.4 X-ray Air Kerma Rate
Under the rated working conditions, the leaking ray air Kerma rate of X-ray device at a
distance of 1 m from X-ray tube focus shall comply with the requirements in Table 1.
20 lp/mm ~ 28 lp/mm, static sensitivity is superior to 2.5% and dynamic sensitivity is
superior to 3.5%. When resolution is excessively low, image sharpness might become
worse; when resolution is excessively high, the signal to noise ratio and dynamic range
of images would become lower.
NOTE: 1 in = 25.4 mm.
Or, in accordance with detailed requirements, flat panel detector and other detectors
may be adopted.
5.6.2 Testing of system resolution
After a system is determined or altered, its resolution shall be tested.
Adopt the radiographic testing system resolution indicator described in GB/T 23903 to
test system resolution. Please refer to Appendix B for system resolution testing method.
5.6.3 Validation of system resolution
Under the condition of unchanged system, in every 30 d, system resolution shall be
validated at least once; validation record shall also be kept. When abnormal image
quality is found, system resolution shall be validated at any time.
6 Imaging Technology
6.1 X-ray Tube Voltage
X-ray energy shall select relatively low tube voltage. Figure 1 stipulates the maximum
X-ray tube voltage that is allowed to be adopted under different materials and different
transillumination thicknesses.
6.5.3 Imaging mode
6.5.3.1 Static imaging
Under the static state of ...