This standard specifies the density measurement method for wire used for rivet contacts. This standard is applicable to various wires used for rivet contacts processed by various methods, and also to other wires used for contacts. JB/T 7780.1-1995 Mechanical and physical properties test of wire used for rivet contacts JB/T7780.1-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Test Methods for Mechanical and Physical Properties of Wire for Rivet Contacts Density Measurement Method for Wire for Rivet Contacts
Subject Content and Scope of Application
This standard specifies the density measurement method for wire for rivet contacts. JB/T7780.11995
This standard is applicable to various types of wire for rivet contacts processed by various methods, and also to other wires for contacts. 2 Principle
The basic principle of density measurement is the Archimedean principle. The sample is first weighed in air and then weighed in liquid, and the density is calculated. 3 SampleWww.bzxZ.net
3.1 The surface of the sample must be smooth, free of oil and cracks. 3.2 When the wire diameter d<2mm, the sample volume V≥0.3cm, and when the wire diameter d≥2mm, the sample volume V≥0.5cm. The minimum sample length should be determined according to the wire diameter, and the formula is as follows; L=4Vx10
Where: L is the shortest sampling length, mm;
V is the sample volume, cm\;
d is the wire diameter, mm.
4 Measuring device
4.1 Precision balance, with a sensitivity of 0.1mg.
4.2 The measuring device is shown in Figures 1 to 3. The hanging wire does not absorb water and has a diameter not greater than 0.25mm. Figure 1m. Weighing
Figure 2m Weighing
Figure 3mz Weighing
4.3 The container size should be selected appropriately, so that when a sample less than 10cm is placed in the liquid, the liquid level will not rise by more than 2.5mm. 4.4 Use distilled water or deionized water to measure the liquid. The density of pure water in air is shown in Table 1. 4.5 Use a thermometer with a minimum scale value of no more than 0.5℃ to measure the liquid temperature. Approved by the Ministry of Machinery Industry in 1995-1009
Implemented in 1996--01--01
JB/T7780.11995
For the convenience of measurement, a long wire sample is wound along a round rod with a diameter of not less than 25mm to form a spiral with a pitch of not less than 2mm. The sample is placed in a plate and the mass m of the sample in the air is weighed. (See Figure 1) 5.3 Place the bracket and the container containing the measuring liquid, hang the hanging wire, and the part of the hanging wire immersed in the liquid is not less than 10mm (see Figure 2). After all bubbles are removed, weigh m1.
5.4 Hang the sample on the hanging wire (see Figure 3), and weigh m2 after all bubbles are removed. 5.5 The measurement must be carried out in an environment of 20±5℃. During the weighing process, the temperature of the sample, liquid and surrounding environment should be the same, and the temperature of the liquid should be measured.
Results expression
The density of the sample is calculated according to formula (2):
Where: D-sample density, g/cm\;
Dmo·D
D,—density of the liquid at the measuring temperature, g/cm; mo--weighing value of the sample in air, g; weighing value of the sample in air (including hanging wire), g; m,
-weighing value of the sample in water (including hanging wire), g. m.
The calculation result is rounded to 0.01g/cm.
Additional remarks:
This standard is proposed and managed by the Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Guilin Electric Science Research Institute. The main drafter of this standard is Jiang Hansong
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