JJG 475-2008 Verification Procedure for Electronic Universal Testing Machines JJG475-2008 Standard download decompression password: www.bzxz.net
This procedure applies to the initial verification, subsequent verification and in-use inspection of electronic universal testing machines. Type evaluation and verification of electronic tension (or pressure) testing machines can refer to this procedure.

This regulation refers to the following documents:
GB/T2611—1992 "General Technical Requirements for Testing Machines"
GB/T16491—1996 "Electronic Universal Testing Machines"
GB/T16825.1—2002 "Verification of Static Uniaxial Testing Machines Part 1: Verification and Calibration of the Force Measuring System of Tension and (or) Compression Testing Machines"
JJG139—1999 "Tension, Compression and Universal Testing Machines"
JJG762—2007 "Extensometer"
When using this regulation, attention should be paid to using the currently valid versions of the above-mentioned references.
1 Scope (1)
2 References (1)
3 Terms and units of measurement (1)
3.1 Resolution (1)
3.2 Discrimination threshold (1)
3.3 Symbols, units and definitions used in this specification (1)
4 Overview (2)
5 Metrological performance requirements (3)
5.1 Classification of testing machines (3)
5.2 Force application system (3)
5.3 Force measurement system (3)
5.4 Allowable error of displacement measurement (4)
5.5 Deformation measurement system (4)
6 General technical requirements (4)
6.1 Appearance (4)
6.2 Testing machine performance (4)
6.3 Moving beam (5)
6.4 Force measuring system (5)
6.5 Safety protection device (5)
6.6 Noise (5)
7 Measuring instrument control (5)
7.1 Verification conditions (5)
7.2 Verification items and verification methods (6)
7.3 Processing of verification results (9)
7.4 Verification cycle (9)
Appendix A Verification record of electronic universal testing machine (10)
Appendix B Format of the inner page of the verification certificate of electronic universal testing machine (13)

National Metrology Verification Regulation of the People's Republic of China JJG 475
Electronic Universal Testing Machine
Electronic Universal Testing Machine2008 - QB - 12 Issued
2008-12.-12 Implementation
The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China issued JJG 4752008
Electronic Universal Testing Machine
Verification Regulation of ElectronicUniversal Testing Machine
-TKAON KAca-
JJG 475-- 2008
Replaces JJG 475—1986
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on June 12, 2008, and took effect on December 12, 2008.
Responsible unit: National Technical Committee on Force and Hardness Metrology Main drafting unit: Shandong Institute of Metrology, China Institute of Metrology
Shanghai Institute of Metrology and Testing
Participating drafting unit: Hubei Institute of Metrology and Testing, Qinglindeng Institute of Metrology and Testing
General Iron and Steel Research Institute
Shenzhen Xinsansi Materials Testing Co., Ltd. Shaoxing Kent Machinery and Electronics Co., Ltd.
Shanghai Hualong Testing Instrument Co., Ltd.
This regulation is entrusted to the National Technical Committee on Force and Hardness Metrology to interpret this regulation Main drafter:
JJG 475—2008
Li Wansheng (Shandong Institute of Metrology) Hu Gang (China Institute of Metrology)
Zhao Yucheng (Shandong Institute of Metrology) Zhang Guiren (Shanghai Institute of Metrology and Testing Technology)
Hu Xiang (Hubei Institute of Metrology and Testing) Qu Zhuo (Jilin Institute of Metrology and Testing) Zhou Weisong (General Iron and Steel Research Institute)
Lei Qing'an (Shenzhen Xinsansi Materials Testing Co., Ltd.) Li Zhaohai (Shaoxing Kent Machinery and Electronics Co., Ltd.) Li Mingyi (Shanghai Hualong Testing Instrument Co., Ltd.) 1 Scope·
References
3 Terms and units of measurement.
3.1 Resolution
3.2 Discrimination
JJG 4T5—2008
3.3 Symbols used in this specification. Units and definitions 4 Overview
5 Metrological performance requirements
5.1 Classification of testing machines -
5. 2 Force system-
5..3 Force measuring system...
6.4 Allowable error of displacement measurement.
6.5 Deformation measuring system.+-
General technical requirements
Appearance*
Testing machine performance
Moving horizontal axis
Force measuring system·
Safety protection device
Noise,
Measuring instrument control
Verification conditions
Verification items and verification force method
Processing of verification results
Verification cycle·
Appendix A
Electronic universal testing machine inspection record
Appendix B
Electronic universal testing machine inspection certificate content format F..T...I..T
-TKAON KAca-
1 Scope
JJG 475—2008
Verification Procedure for Electronic Universal Testing Machines
This procedure applies to the initial verification, subsequent verification and in-service inspection of electronic universal testing machines (hereinafter referred to as testing machines). Type evaluation and verification of electronic tension (or pressure) testing machines can refer to this procedure. 2
References
This specification refers to the following documents:
GE/T2611-1992 General Technical Requirements for Testing Machines" GB/T16491-1996 "Electronic Force Testing Machines" GB/T16825.1-2002 "Verification of Static Uniaxial Testing Machines Part 1: Verification and Calibration of the Force Measuring System of Tension and (or) Compression Testing Machines"
JJ0139-1999 "Tension, Force and Universal Testing Machines" JIG762--2007 "Extensometer"
When using this specification, the current valid versions of the above-mentioned references should be used. 3 Terms and Units of Measurement
3. 1 Resolutionbzxz.net
resolution
The ability of an indicating device to meaningfully distinguish between two adjacent values ​​of the indicated quantity. 3.2 Discrimination threshold is the maximum input change that produces an imperceptible change in the indication of the testing machine in response to the change. 3.3 The symbols, units and definitions used in this specification are shown in Table 1.
Table 1 Symbols, units and definitions
Measurement range of each gear of the force indicating device of the testing machine Large capacity of the process indication of the force indicating device of the tested testing machine Return indication of the force indicating device of the tested testing machine True value of the force indicated by the process indication of the standard dynamometer
True value of the force indicated by the process indication of the standard dynamometer The arithmetic mean of the indication F of the force at the same measuring point in the measurement disk The arithmetic mean of the true value of the force F at the same measuring point in multiple measurements Maximum value of the indication F at the same measuring point
Minimum value of the indication F at the same measuring point
4 Overview
mm/min
JG 475—2008
Table 1 (continued)
Maximum value of the true value F of the force at the same measuring point
Minimum value of the true value F of the force at the same measuring point
Residual indication of the force indicating device of the tested testing machine after the force is removedResolution of the indicating device of the testing machineRelative resolution of the indicating device of the testing machine
Relative resolution of the indicating device of the testing machine
Repeatability of indication of the force measuring system of the testing machineRelative error of the zero point
Relative error of indication of the force measuring system of the testing machineRelative error of indication
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At the same measuring point, in the same test, the deformation on the side of the test specimen with larger deformation is measured at the same measuring point. In the same test, the arithmetic half-mean of the deformation on both sides of the test specimen is measured. At the same moving beam speed, the arithmetic mean of the three measuring speeds is the standard value of the beam moving speed
Test force at the root
Force system zero drift indication
In the three tests at the same time, the arithmetic mean of the displacement indication corresponds to the measured beam displacement, the true value of the displacement indicated by the test calibrator (or thousandths) or steel ruler. Coaxiality of the force system of the test machine
Relative error of beam speed
Zero drift error of the force measuring system
Relative error of beam displacement indication
Electronic force testing machine is a mechanical force testing machine controlled and measured by a computer. It is mainly used for tensile, compression, bending and shearing mechanical properties tests of metal and non-metal materials. 2
5 Metrological performance requirements
5.1 Classification of testing machines
JJG475-2008
The levels of testing machines and the allowable errors of each item are shown in Table 2. Table 2 Levels of testing machines and the allowable errors of each item
Maximum allowable value/%
Testing machine
Relative error of indication
5.2 Force system
Repeatability of indication
Relative error of indication in and out
5.2.1 The center line of the specimen holding device for tensile test shall be coaxial with the force axis of the testing machine at any position and during the process of applying force. The coaxiality of the testing machine with a maximum test force not exceeding 5 kN shall not exceed $2 mm. The coaxiality of the testing machine with a maximum test force not exceeding 2 kN shall comply with the provisions of Table 3. 5.2.2 Moving frame beam moving speed range is usually between the following two numbers. |Grading:
1X10, 2XN
n=0, ±1, ±2, ±3
Maximum allowable value of coaxiality
mm/min internal selection
N0\5X10°
METROLOG
The beam speed for selection should not be less than 1
Relative division
Lower chuck and specimen jaws
When graded speed regulation is adopted
5.2.2.2 Under zero test force conditions, the relative error between the beam speed and the selected speed nominal value shall comply with the provisions of Table 4. Table 4 Relative error of beam speed
Testing machine level
Relative error of beam speed/%
5.3 Force measurement system
5.3.1 Before using the testing machine, the preheating time should not exceed 30 minutes: the zero drift within 15 minutes after preheating should comply with the requirements of Table 5.
Testing machine level
Zero drift
Discrimination
JJG 475-2(H08
Table 5
Zero drift
Discrimination valve of the force measuring system of the testing machine should not be greater than 1.0. 3.3 Allowable errors and relative resolution Hall 1
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The relative error of the indication of the force measuring system of the testing machine 9, the relative error of the indication repeatability, the relative error of the indication forward and return stroke, the relative error of the indication point and the relative resolution should conform to the formula of Table 2. 5.4 Allowable error of displacement measurement
5.4.1 The resolution of the moving beam displacement indicating device should not be greater than 0.02mm. 5.4.2 The relative error of the displacement indication of the moving beam should not exceed 0.5%5. 5
Deformation measurement system
Deformation measurement system, i.e., an extensometer system composed of deformation sensors with different degrees of accuracy and deformation measurement resistance of the testing machine (hereinafter referred to as extensometer). According to JJG762-·2007, the maximum allowable values ​​of indication error of each level of extensometer are shown in Table 6.
6 Indication error of extensometer
Extensometer level
General technical requirements
B.1 Appearance
Absolute error/μm
Indication error
Relative error/%
±1, 0
6.1.1 The test machine should have a nameplate, which should include: name, model, specification, accuracy level, manufacturer name, mark, batch number and date.
6.1.2 The test machine should be installed on a stable foundation, and its installation level should not exceed 0.2/1000. There should be no less than 0.7 square meters of space around the test machine. The basic working environment should be clean, without exposure, corrosive media and strong electromagnetic field interference. The change of power supply voltage should be within ±10% of the rated voltage. 6.1.3 The electrical control of the test machine should be safe, reliable and flexible. The data measurement, transmission, calculation, display and printing systems should be accurate.
6.2 Test machine performance
The test machine frame should have sufficient rigidity and test space, and should be able to easily carry out various tests and facilitate the specimen. 4
JJG. 475—2008
Installation and use of specimen clamping device, test machine accessories and standard force gauge. The test machine should be stable and free of shock and vibration during the process of applying and removing force. The accessories of the test machine should comply with the requirements of GB/T16491-1996 and related test methods.
6.3 Moving beam
6.3.1 The horizontality of the moving beam should be within 0.2/1000. The moving beam should be stable when moving within the working stroke. 6.3.2 The guide parts of the moving beam or the chuck should not have obvious wear or defects. 6.3.3 The installation of the column and the fixed crossbar should not be loose. 6. 4 Force measuring system
6.4.1 The force measuring system should be able to continuously indicate the test force applied to the specimen at any time. The force indication should be stable during the process of applying or removing the test force, without shock, stagnation and abnormal band jump. 6.4.2 The testing machine shall be able to accurately indicate and retain the maximum test force before the specimen breaks or is turned over. 6.4.3 The force measuring system shall have the function of withering or clearing. The force measuring system shall generally have a calibration procedure that is convenient for verification. 6.4.4
6.4.5 Indicator
6.4.5.1 The displayed numbers shall be clear and easy to read. It shall be able to display the zero point and maximum value of its indication range and the symbol indicating the force application method (such as "ten" or "one"), and shall directly display the test force value in units of force. 6.4.5.2 Determination of resolution
: - The motor and control system of the testing machine are both started, and under no-load conditions, if the indication of the digital indicating device changes by no more than one increment, then its resolution is considered to be one increment. - If the indication changes by more than one increment, then the resolution at this time is considered to be equal to half of the range plus one increment.
6. 4. 6 Recording device
The testing machine should be able to draw force-deformation, force-displacement, force-time curves through the recording device. According to user needs, it can also draw stress-strain curves, etc.
6.5 Safety protection device
6.5.1 The safety device of the testing machine should be sensitive and reliable. When the test force exceeds 2% to 10% of the maximum test force of each measuring range, the safety device should be activated immediately and automatically shut down. 6.5.2 The electrical equipment is safe and reliable without full power phenomenon. The insulation resistance between its power cord and the casing should be greater than 2MQ6.5.3 After the sample is broken, the testing machine should automatically stop. When the moving crossbeam of the testing machine moves to the upper and lower limit positions of its working range, the limit device should be activated immediately to stop it from moving automatically. 6.6 Noise
The noise level during the operation of the testing machine shall not exceed 70dB(A) for the testing machine with the maximum test force less than 500kV, and shall not exceed 75dB(A) for the testing machine with the maximum test force not less than 500kN. 7 Measuring instrument control
7.1 Verification conditions
7.1.1 Environmental case
The testing machine shall be verified at room temperature of (10～35)℃ and relative humidity not more than 80%. The temperature fluctuation during the verification process shall not exceed 2℃
7.1.2 Standard instruments for verification
JJG4752008
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7.1.2.1 To verify the 0.5-level testing machine, use a 0.1-level standard dynamometer or a special base code with a reproduced force value error within ±0.1%. For the verification of the test machines of level 1 and 2, a 0.3 level standard dynamometer or a special brick code with a force value error of ±0.1% shall be used.
7.1.2.2 A coaxiality tester (or other measuring device with equivalent accuracy) or a weight with an accuracy of ±2% shall be used. 71.2.3 A stopwatch with a resolution of 0.018.
71.2.4 (0~30)mm range of the first-class micrometer 71.2.5 Graduation value 0.02mm/mk level meter
7.1.2.6 Sound level meter (A meter authorized network)
Extensometer calibrator
Paper chicken
Steel or copper
Less than 10mm
Verification items and
Verification items
Appearance, performance
Beam movement
Your error of the calibrator
m range of the first-class micrometer and magnetic base, allowable error
Coaxiality inspection with the system
The coaxiality of the part of the specimen with uneven gauge length and the two heads For the whole device, the indication of crossbeam displacement, source displacement, discrimination, zero point relative error, test element value relative error, test force indication repeatability relative error, test force indication forward and return stroke relative error, test force indication relative resolution, extensometer indication error, items that need to be calibrated: 7.2.1 Inspection of general technical requirements List of calibration items Less than 100 mm Continuous calibration METROLOGY Items that do not need to be calibrated. *Limited to 0.5 grade
Interval part diameter pass
In-use inspection
Through visual inspection, hand feeling and corresponding general measuring instruments, check 6.1~6.4 items. After the inspection meets the requirements, other items can be calibrated.
7.2.2 Verification of coaxiality
JJG475-2008
Coaxiality should be calibrated by the following two methods: a) For testing machines not greater than 5kN, use the heavy hammer method for inspection. During the inspection, the stretching space should be no less than 500mm, and a heavy hammer should be hung at the upper force center. The center of the heavy hammer should be within a circle with a diameter of 2mm with the lower force center as the center.
b) For testing machines greater than 5kN, use a coaxiality tester (or other measuring devices of corresponding accuracy) for verification. During the calibration, first clamp the test specimen on the head and apply an initial force of 1% of the maximum test force of the testing machine. Adjust the coaxiality measuring instrument to 4% of the maximum test force. The maximum force used in the test should not cause the test specimen to deform rigidly. Measure the elastic deformation of the two opposite sides of the specimen, and measure 3 times in the mutually perpendicular directions. The coaxiality is calculated according to formula (1). The result of each calibration should meet the requirements of Table 3. AL
7.2.3 Inspection of beam movement speed
In the range of beam movement speed, select the highest, lowest and middle three measurement points below 0.05mm/min speed does not require further inspection). Use a stopwatch and select one of the micrometer, dial gauge or steel ruler H
to measure and test three times according to the speed. The result should meet the requirements of Table 4. The relative error of beam speed W is calculated according to formula (2) P
7.2.4 Verification of relative error of lateral displacement indication S
Select two measurement ranges of 1% and 50% of the maximum displacement at any position within the working range of the mobile sample for verification. Each measurement range is verified three times. The verification results should meet the requirements of Articles 5 and 4. The relative error q of the beam displacement indication is calculated according to formula (3): DD
7.2.5 Inspection of zero drift: For a test machine with steps, select the minimum test force range. After the test machine is preheated, adjust the zero point and inspect the zero drift within the specified time: AMETROLOG
. The result should meet the requirements of Table 5. The zero drift is calculated according to formula (4): Fed×100%
For a test machine without steps, 5 times the lower limit of measurement can be taken as F. 7.2.6 Inspection of discrimination: Select the minimum measurement range of the test machine. Under zero test force, when a force of 10 is applied, the digital display device should produce at least one digital increment change. 7.2.7 Inspection of relative resolution: The relative resolution a of the force indicating device is calculated according to formula (5): The result meets the requirements of Table 2.
7.2.8 Verification of various permissible errors
JJG 475--2008
×100%
FTKAONTKACa-
7.2.8.1 The dynamometer should be placed on the testing machine for a sufficient time to reach a stable temperature. If necessary, the reading should be corrected for temperature.
7.2.8.2 When installing a tension dynamometer on the testing machine, any bending effect should be minimized. When installing a compression dynamometer, ensure that there is only one ball seat between the testing machine and the standard dynamometer. .2.8.3 The testing machine with the installed dynamometer should be applied to the maximum test force at least three times from the beginning. .2.8.1 The following method should be used to calibrate the testing machine: Apply the given force F indicated by its force indicating device to the testing machine. Record the actual force F indicated by the dynamometer. If the above method cannot be used, apply the actual force F indicated by the dynamometer to the testing machine and record the force F indicated by the force indicating device of the tested testing machine. Selection of verification points
7.2. 8.51
a) For multi-range testing machines: There shall be no less than 5 verification points for each measuring range, generally evenly distributed at 20%, 40%, 60%, 80%, and 100% of each range. b) For single-range testing machines: Select verification points at approximately equal intervals within the range of 20% to 100% of the full scale. For verification points below 20% of the full scale, select points approximately equal to 10%, 5%, 2%, 1%, 0.5%, 0.2%, and 0.1% to the lower limit of the range. Note: The lower limit of the measuring range is determined by the multiple of the resolution: 0.5 level 100r
Level 1: 200r:
Level -2: 100r.
For the testing machine with automatic change of measuring range, at least two calibration points shall be selected in each range where the resolution does not change.
7. 2. 8. 6
Three groups of measurements shall be carried out in an increasing manner. The zero point shall be adjusted before each group of measurements. The zero point reading shall be read about 60s after the force is completely removed.
The relative error of the zero point is calculated according to formula (6):
x ​​160%
7.2.8.7 Relative error of indication and relative error of indication repeatability (6)
Calculate the arithmetic mean of the three measurements at each calibration point. And calculate the relative error of indication and relative error of indication repeatability by the following formula.
（a）When reading on the dynamometer based on the indicating device of the testing machine, the relative error of indication 9 and the relative error of indication repeatability are calculated according to the following formula:
×100%
Fm - Fn ×100%
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