Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of the National Technical Committee on Testing Machines of Standardization Administration of China (SAC/TC122).
Non-destructive testing instruments—Ultrasonic time-of-flight diffraction instrument—
Methods of performance tests
1 Scope
This standard specifies the methods of performance tests for ultrasonic time-of-flight diffraction (UTOFD) instrument.
This standard is applicable to UTOFD instrument.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 12604.1 Non-destructive testing—Terminology—Terms used in ultrasonic testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T12604.1 and the following apply.
3.1
sampling rate
number of samples collected per unit time during analog-to-digital conversion of analog signal
Note: The unit of sampling rate identifies with that of frequency in Hz.
3.2
ultrasonic time-of-flight diffraction; UTOFD
propagation time of ultrasonic diffraction sound wave
3.3
ultrasonic time-of-flight diffraction instrument
UTOFD instrument
instrument that realizes nondestructive testing by detecting UTOFD at two ends of a defect and calculating their time difference
3.4
UTOFD instrument sampling rate
largest sampling rate that the hardware of the UTOFD instrument can actually achieve
3.5
sampling accuracy
bit depth
accuracy that can be achieved when the UTOFD instrument digitizes the amplitude of analog signal sample
Note: Sampling accuracy, in bit, is usually expressed in bits of binary number used in analog-to-digital quantization. The larger the number of bits, the higher the sampling accuracy.
3.6
collection depth
storage depth
number of sampling data points that can be stored in a real-time collection of analog signal by UTOFD instrument
Note: The unit of collection depth is thousands of points.
3.7
time windows length
number of sampling data points contained in the window based on the rectangular window
3.8
response time
time required from detection until an 80% instantaneous echo is displayed on the screen
3.9
dynamic range
ratio of amplitude of the maximum signal to the minimum signal that the UTOFD instrument can display, where the latter is limited by system noise, while the former is limited by amplifier saturation
3.10
cross-talk damping during transmission
amount of energy leakage damping from the transmitter output end to the receiver input end in the transmission process of transmission pulse when the UTOFD instrument is operated with twin transducer probe (transmitter and receiver are separated)
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4 Test method
4.1 Test conditions
The UTOFD instrument shall be tested under the following conditions:
a) Ambient temperature: 20°C±5°C;
b) Relative humidity: 45%~75%;
c) AC supply voltage: 220 V, with an error of ±2%;
d) AC power supply frequency: 50Hz, with an error of ±1Hz;
e) DC supply voltage, with an error of ±1% of the rated value;
f) Without external electromagnetic interference;
g) With good ventilation;
h) Without direct sunlight.
4.2 Apparatus
The performance and stability of the electronic instruments used shall meet the testing requirements. The following main apparatus are adopted:
a) Oscilloscope with a bandwidth of not less than 100MHz.
b) 50 ? and 75 ? non-inductive resistors, with the maximum allowable relative error of ±1%.
c) Standard attenuator with a step of 1 dB, a total attenuation of 100 dB, and an output impedance of 50Ω, the cumulative error of which within any 10dB range shall be within ± 0.3 dB for signals with a frequency of not greater than 15MHz.
d) One of the following two generators:
1) An arbitrary waveform generator;
2) Two pulse signal generators with external triggers or gates, capable of producing two gated bursts of sinusoidal radio frequency signals, the amplitudes of which shall be independently variable by up to 20 dB.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Test method
