This standard is applicable to the determination of the ball indentation hardness of plastics when a steel ball is pressed into the specimen under a specified load. GB/T 3398-1982 Plastic ball indentation hardness test method GB/T3398-1982 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test for hardness of plastics by the ball indentation
Unc 678.5
GB 339B--B2
This standard is applicable to the determination of the ball indentation hardness of plastics when a steel ball is pressed into a specimen under a specified load. This standard is formulated with reference to International Standard ISO 2039-73 "Plastics and hard rubbers - Determination of ball indentation hardness". 1 Definition
Ball indentation hardness refers to the average pressure on the single indentation area after a steel ball of a specified diameter is pressed vertically into the surface of the specimen under the test load and maintained for a period of time: expressed in kgf/mm2 or N/mm2. 2 Instrument
The ball indentation hardness tester shall consist of a frame, an indenter, a loading device, an indentation depth indicator and a tester. 2. The frame should be a rigid structure. Under the maximum load, the deformation along the axis should not exceed 0.05mm. The frame is equipped with a lowerable workbench.
2.1.1 The axial misalignment between the lifting table and the axis of the 1 axis should not be greater than (.2mm. 2.1.2 The main transmission axis and the lifting table should be aligned, and the deviation should not exceed 0.2%. 2.1.3 The indication accuracy of the hardness gauge should be ±4%. 2.2 The chuck is a fire-polished steel ball with a diameter of 5mm and a hardness of approximately 800Hv. The tolerance should be within ±0.5% of the standard diameter. The ball should not be deformed or damaged under the test load. 2.3 The loading device includes a lever, a brick code and a buffer, and the following loads can be added to the pressure bottle. The initial load is 1.00kgt (9.8V):
The test load is 5.00kgf (49N)
13.5kgf (132N):
36.5kgf (35hN)
98.0kgl (961N).
The allowable error of each load level is 1%.
The buffer should allow the indenter to load the sample smoothly and without impact, and control the loading time within 2 to 3 seconds. 2.4 The pressure depth indicator is a device for measuring the depth of the indenter. In the 0~0.5mm measurement range: the accuracy is 0.005mm. 2.5 The timing device can indicate the time from the time when the test load is fully applied to the time when the positive mark depth is read. The timing range is not less than 10 60s and the accuracy is ±5%.
2.6 The hardness tester should be retrograde calibrated regularly.
3 Sample ||t t||- is generally - years. bzxz.net
3.1 The specimen should be of uniform thickness, smooth and flat surface, free of bubbles, inorganic alkali damage and impurities. 3.2 The thickness of the specimen should not be less than 104mm. The specimen size should ensure that the distance between the center of each measuring point and the edge of the specimen is not less than 10mm, and the distance between the centers of each measuring point is not less than 10m2. When using non-planar test clothes or other shapes, the specimen size shall be specified separately by the relevant product standards. Note: The recommended specimen size is 50×4mm or 50×4mm. Issued by the National Bureau of Standards on December 29, 1982
Implementation on October 1, 1983
4 Test steps
GB3398-82
4.1 According to GB 1039-79 "General Rules for Testing Methods of Mechanical Properties of Plastics" Article 2 and 4 shall be used to inspect and process the specimens, and the test environment shall be adjusted in accordance with Article 2 of GB2918-82 "Standard Environment for Conditioning and Testing of Plastic Specimens". Product standards and regulations are allowed. 4.2 Regularly measure the deformation of the frame under various loads. When measuring, remove the head and lift the workbench to make it contact with the spindle. Add the initial load, adjust the depth indicator to zero, add the test negative section, and directly read the frame deformation h, (mm) under the corresponding load from the indentation depth indicator.
4.8 Select an appropriate test load according to the hardness of the material. Install the indenter and place the specimen on the workbench so that the test surface is in vertical contact with the loading direction. After the initial load is applied, adjust the depth indicator to zero. 4.4 Apply the selected test load semi-steadily to the specimen within 2 to 3 seconds, keep the negative pressure for 30 seconds (according to the product standard), and immediately read the indentation depth h, (mm).
4.5 The indentation depth must be within the range of 0.15~0.35mm. If the indentation depth is not within the specified range, the test load should be changed to reach the specified depth range.
,6 Each group of specimens shall be at least two pieces, and the number of measurement points shall be at least 10. 5 Calculation and expression of results
5.1 The ball indentation hardness value is calculated as follows:
H= 0.25 yuan (h-0.04)
Wherein: I——ball indentation hardness, kgf/mm2 or N/mm*:-test load, kgf or;
—true diameter of steel ball, mm;
h——indentation depth after deformation of calibration machine frame, mm. Note: h=hr-h21
h-indentation depth under test load, mm
h:---deformation of the frame of the instrument under the test load, mm. 5.2 The test results are expressed as the arithmetic mean of a group of specimens, taking three significant figures. 5.3 If standard deviation is required, it can be calculated according to the following formula: S=
-measured value of a single specimen:
arithmetic mean of the measurement results of a group of specimens: n—number of measured specimens.
6 Test report||tt| |The test report shall include the following contents:
Material name, specification, source and production team,
b. Sample shape, size and preparation method; E(XX)
Test temperature, humidity, state conditioning time and test load: Test times and the number of tests that did not reach the specified indentation depth range d.
Average value and standard deviation of ball indentation hardness ()
Test period, test personnel.
GB3398—82
Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and was drafted by the Physical and Mechanical Test Method Branch of the National Technical Committee for Plastic Standardization.
This standard was drafted by the Chenguang Chemical Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Li Lihua and He Bingmei.
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