HG/T 2488-1993 Determination of tensile properties of rubber threads HG/T2488-1993 standard download decompression password: www.bzxz.net

Chemical Industry Standard of the People's Republic of China
Determination of tensile properties of rubber thread
This standard is equivalent to the international standard ISO2321-1983 "Rubber thread - Main content and scope of application"
HG / T 2488 —93
—Test Methods》Part VII and Part VIII This standard specifies the method for determining the tensile strength and elongation at break of rubber threads. This standard is applicable to rubber threads made of natural rubber, natural latex and synthetic isoprene rubber. 2
Referenced Standards
GB/T2941 Standard temperature, humidity and time for environmental conditioning and testing of rubber specimens HG/T2412.2 Test methods for rubber threads Determination of rubber thread count HG/T2412.3 Test methods for rubber threads Determination of rubber thread density 3 Test apparatus
Dynamometer (accuracy ±2%), equipped with a suitable fixture to avoid damage to the specimen and a scale with a 1mm graduation for measuring elongation.
3.1 or 3.2 can be used. Specified devices, 3.1 Rigid fixture
3.1.1 The moving speed of the test machine fixture should be 500±50mm/mim3.1.2 Each fixture should have a square rigid surface clamp of about 25mm, see Figure 1.3.1.3 The male clamp of each fixture should have a rigid convex surface with a radius of 5±3mm and a width of 25mm, see Figure 1 Approved by the Ministry of Chemical Industry of the People's Republic of China on July 5, 19934
Implemented on December 1, 1994
Twist the mouth
HG/T2488
3.1.4 There should be a full rubber hose with an inner diameter of about 1.6mm and a wall thickness of 0.8mm and a wire guide or other device that can insert the rubber wire into the hose.
3.1.5 The scale for measuring elongation should be parallel to the specimen 3.2. Rotating roller fixture
Figure 2 shows a suitable device, including the following parts: a spring dynamometer;
an inert pulley that can rotate freely, directly connected to the free end of the spring, and freely move in the arc direction of the spring: two driven winding rollers with grooves, or other devices that can be embedded in the end of the specimen. The diameters of the rollers and the inertia wheel are in the range of 25 to 30mx and their diameters should be similar. The winding rollers should be rotated by a motor at a surface linear speed of 60mm/s in the direction shown, and the path of the rubber wire between the rollers should be between 259 and 400mm. All rollers or inertia wheels should have smooth surfaces. The scale for measuring elongation should be parallel to the specimen
4 Specimen
HG/T2488-93
Figure 2 Apparatus for determining tensile properties
a spring dynamometer; ② an intermediate pulley; @ a winding wheel, 4.1 The specimen should have an appropriate length for the testing machine used. 4.2 Each specimen should be marked with a gauge length of not less than 30 mm. 5 Test steps
5.1 Rigid fixture method
5.1.1 Prepare 5 rubber wire specimens with a length of 125~150 mm. One or more rubber wires can be used as one specimen. 51.2 Place the specimens in accordance with the provisions of GB294t. 5.1.3 Mark the specimens with an initial gauge length of 50 mm using ink. 5.1.4 Place the clamps specified in 3.1.2 and 3.1.3 on the testing machine so that the axis of the raised surface is horizontal and the center of the clamp is in the center. Note:
1) ISO2321-83 stipulates that the length of the specimen is about 125 mm. IIG/T 2488-93
Cut two full rubber hoses with a length of 10-20 mm 50 mm apart and pass the specimen through the hose. The rubber wire of each pair shall not be less than 25 mm beyond the hose. First, fix the hose with the rubber wire specimen on the upper clamp, straighten the specimen and adjust the hose at the other end to eliminate the slack part of the specimen, and then fix the hose on the lower clamp. 5.1.5 Select the force dial of the dynamometer so that its accuracy reaches 2%. 5.1.6 Start the testing machine, observe the stretched specimen, and record the gauge length and load value when the specimen breaks. If the specimen breaks within 3 mm of any clamp, the test result is invalid and another specimen shall be tested. 5.2 Rotating drum method
5.2.1 Prepare 5 specimens, each consisting of an appropriate number of rubber threads so that an appropriate force value can be obtained when it breaks. 5.2.2 Start the test device and track the increasing distance of the reference marks on the scale. When the specimen breaks, read the position reached by the two reference marks on the scale. Record the length and load value reached by the reference mark when the specimen breaks. 6. Result Expression
6.1 Calculate the initial cross-sectional area of ​​a single rubber wire according to the requirements of IIG/T 2412.2 and HG/T 2412.3. 6.2 Tensile strength R. Calculate according to formula (1): R
Where: R is tensile strength, MPa:
is the load value when the specimen breaks, N;
is the initial cross-sectional area of ​​a single specimen, mm2; H is the number of ends of the rubber wire connected to the tensile gauge. 6.3 The elongation at break A is expressed as a percentage of the specimen length and is calculated according to formula (2): A
is the elongation at break, %:
Where: -
L is the initial gauge length of the specimen, mm; L is the gauge length when the specimen breaks, mm. x100
6.4 Take the median value of 5 samples to express the tensile strength and elongation at break of the rubber wire, and indicate the maximum and minimum values7Www.bzxZ.net
Test report
The test report should include the following contents:
The source and identification mark of the sample;
The standard and standard number of the test basis;
The number of samples;
The test method and equipment adopted;
The temperature and humidity of the test;
Test results;
The test period;
The tester,
HG / T 2488 — 93
Additional remarks:
This standard is proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Latex Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by Shenyang Latex Factory. The main drafters of this standard are Zhang Zhenyang, Wang Jingru and Liu Chunhong.
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