GB 4909.2-1985 Bare wire test method dimensional measurement

This test method is applicable to measuring the dimensions, fillet radius, pitch-diameter ratio and cross-sectional area of ​​various circular, rectangular and special-shaped conductors and bare wires. When there are higher requirements for the measurement accuracy of the dimensions, it should be clearly specified in the corresponding standards. GB 4909.2-1985 Bare wire test method Dimension measurement GB4909.2-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for bare wires
Measurement of dimensions
The provisions of this standard refer to the relevant provisions of the international standard IEC251 (1978). 1 Scope of application
UDC 621.315.14
GB 4909.2---85
1.1 This test method is applicable to the measurement of the overall dimensions, fillet radius, pitch-diameter ratio and cross-sectional area of ​​various circular, rectangular and special-shaped conductors and bare wires.
1.2 When there are higher requirements for the measurement accuracy of the overall dimensions, etc., it should be clearly specified in the corresponding standards. 2 Measuring tools
2.1 Micrometer
2.1.1 The outer diameter micrometer shall comply with the provisions of GB1216-75 "Micrometer", and the lever micrometer shall comply with the provisions of JB1087-75 "Lever micrometer".
The measuring force of the dry micrometer shall be 0.75~1.25N. When the nominal value of the conductor diameter and size is greater than 0.5mm, the measuring force shall be 1~3N. The diameter of the measuring rod and the measuring seat shall be 5~～8mm.
2.1.2 Other suitable measuring tools are allowed. 2.2 Vernier caliper shall comply with the provisions of GB1214-75 "Vernier caliper" 2.3 Steel ruler 1m long.
2.4 The magnification of the projector or magnifying glass is 10~20 times. 2.5 Special sample standard sample or limit sample. 2.6 Feeler gauge
2.1 Precision balance
Weighing pan range: 0~200gt Sensitivity: 0.1mg1 Weighing range: 1kg, sensitivity: 1mg. bZxz.net
3 Sample preparation
3.1 Take 1 sample of solid round conductor, the length of which shall not be less than 1m. 3.2 Take 1 sample of stranded round conductor, the length of which shall be 3~5m. When sampling, pre-tighten the cut part. 8.3 Take 1 sample of non-circular cross-section conductor, the length of which shall be about 0.5~1m. 3.4 When measuring directly on a coiled or coiled sample, it shall be at least 1m away from the end. When measuring on a bundled sample, it shall be measured at both ends at least 200mm away from the end. Measure three points on each sample, and the distance between each measuring point shall not be less than 200mm. 4 Measurement steps
4.1 Measuring tools The measuring tools used to measure various sizes shall comply with the provisions in the table. Issued by the State Bureau of Standards on January 31, 1985
Implementation on December 1, 1985
Nominal size
0.020~0.100
0,101 ~0.250
Above 0.251
10.00 and above
GB4909.2—85
Name of measuring tool
Lever micrometer
Outer diameter micrometer
Outer diameter micrometer*
Vernier caliper*
Indication error (mm)
4.2 The diameter shall be measured on the same section perpendicular to the axis of the specimen in mutually perpendicular directions, and at least three places shall be measured at both ends and the middle of the specimen.
4. Dimensions of non-circular cross-section
4.3.1 Wide side (side b)
Measure once at both ends and in the middle of the straight specimen. 4.8.2 Narrow side (side a)
Measure once at both ends and in the middle of the straight specimen if the wide side is 4.00mm or less. Measure once at both ends and in the middle of the straight specimen if the wide side is 4.01-10.00mm. Measure once at both sides of the plane at both ends and in the middle of the straight specimen if the wide side is more than 10.00mm. Measure once at both sides and in the middle of each plane at both ends and in the middle of the straight specimen. When measuring the plane, about half of the area of ​​the micrometer end plane is in contact with the specimen plane. 4.4 Side bend (sickle bend) Take a specimen with a length of 1-3m, place it on the test platform, place a 1m steel ruler close to the inward bending side of the specimen side a, and then measure the maximum distance between the ruler and side a. 4.5 The fillet radius and angle are measured with a sample, or a specimen with a cross section perpendicular to the axis of the specimen is cut and polished, and then measured by comparing with a special sample using a 20x magnifying glass or a projector.
4.6 Cross-sectional area
4.6.1 The cross-sectional area of ​​a simple cross-sectional specimen can be reasonably calculated from the linear cross-sectional dimensions. When measuring the dimensions, the specimen should be measured at least three times at approximately equal intervals along the measuring length of the specimen, and the arithmetic mean should be calculated. The ratio of the standard deviation of the mean to the mean itself should not exceed ±0.50%. 4.6.2 For specimens with more complex cross-sections, or when the error of the average cross-sectional area calculated from direct measurement exceeds 0.50%, the weighing method should be used for measurement. The weighing should be carried out in accordance with Article 5 of GB3048.2-83 "Test Method for Resistivity of Metal Conductor Materials for Wires and Cables", and the measurement error should comply with the requirements of routine test requirements. 4.7 Stranding pitch
4.7.1 Direct method Lay a 3-5m long stranded wire sample flat and straighten it, and place a steel ruler close to the sample along the axial direction of the sample to measure the distance between the (n+1) strands. n is the number of strands in this layer. 4.7.2 Paper tape method Lay a thin paper tape close to the sample surface along the axial direction of the sample, use a pencil or other appropriate method to copy the stranding stripes of this layer of strands, and then use a steel tape to measure the distance between the (n+1) strands. 4.7.3 Average method Use a steel tape parallel to the axis of the sample to measure the length L of 10, 20 or 50 pitches, and then calculate the average pitch value according to ! =L/n. \ is the number of measured pitches. 6 "Test results and calculations
6.1 The measurement results of the diameter, narrow side and wide side are calculated according to the following formula: * The measuring tool used should be specified in the corresponding standard according to the accuracy requirements of the size. In the formula: X, -
The i-th measurement value, mm,
Number of measurements.
CB 4808.2--85
When calculating, the dimensions of 0.020~1.000mm are retained to three decimal places, and those greater than 1.000mm are retained to two decimal places. The dimensions are rounded according to the method specified in Appendix C of GB1.1-81 "General Provisions for Writing Standards in the Guidelines for Standardization Work". The dimensional deviation value is the difference between the nominal value and the actual measured average value of the dimension (X). 6.2 The value is defined by the difference between the maximum reading and the minimum reading measured on the same section. Measure according to Article 4.2. The test result takes the maximum value of the diameter difference measured on the three sections as the value. 5.3 The measurement results of the cross-sectional area shall be calculated in the following manner 5.3.1 Simple cross-section test specimen
The cross-sectional area S of a solid circular conductor
The cross-sectional area S1 of a stranded circular conductor:
The cross-sectional areas S, and S2 of a rectangular conductor:
Where? S2
The calculated value with rounded corners!
The calculated value without rounded corners;
S, = d?
×n(mm2)
S, =α×h -0.858r2 (mm2)
Sz =axb (mm2)
The measured value of the diameter of a solid single conductor shall comply with the provisions of formula (1); The measured values ​​of the narrow side and the wide side shall comply with the provisions of formula (1); the number of solid conductors in the stranded conductor, the fillet radius of the test specimen, mm.
5.3.2 The cross-sectional area measurement result of the complex cross-section specimen is calculated as follows: S=
Wherein, m-
×10(mm2)
Weigh the apparent mass of the measured specimen, B, accurate to ±0.10%L
-specimen length, mm, accurate to ±0.20%, ds
-sample density, g/cm3, accurate to ±0.45%. Additional remarks:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Shanghai Cable Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Cable Research Institute of the Ministry of Machinery Industry and others. The drafting persons for this standard are Shen Jianhua and Wu Musheng. (2)
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