Tensile strength tester under the condition of constant speed loading, the specimen of specified size is stretched to fracture, the tensile strength is measured, and the maximum elongation at fracture is recorded.
ⅠDefine
The following definitions are adopted in this international Standard.
1,Tensile strength
The maximum tension that paper or cardboard can withstand.
2. Breaking length
The width of the paper itself will be consistent with the quality of the paper will be broken when the length required. It is quantitatively calculated from the tensile strength and constant humidity of the sample.
3.Stretch at break
The elongation of paper or board under tension to fracture, expressed as a percentage of the length of the original specimen.
4, Tensile index
The tensile strength is divided by a quantity expressed in Newtons meters per gram.
Ⅱ The instrument
The tensile strength tester should be able to be used for testing the tensile strength and elongation of the specimen at the specified constant rate of loading. Tensile strength tester shall include:
1. Measuring and recording device
The accuracy of tensile resistance at fracture should be 1%, and the reading accuracy of elongation should be 0.5mm. The effective measurement range of tensile strength tester should be between 20% and 90% of the total range. Note: for paper with elongation less than 2%, if it is not accurate to use pendulum tester to determine elongation, a constant speed tester with electronic amplifier and recorder should be used.
2. Adjustment of loading speed
Note: In order to meet the requirement that the change of loading rate should not be greater than 5%, the pendulum type instrument should not be operated at a pendulum Angle greater than 50°.
3. Two sample clips
Specimens should be clamped together throughout their width and should not slide or damage them. The center line of the clamp should be coaxial with the center line of the sample, and the direction of the clamping force should be 1 ° vertical to the length direction of the sample. The surface or line of the two clips should be 1° parallel.
4, two clip spacing
The distance between the two clips is adjustable and should be adjusted to the required test length value, but the error should not exceed 1.0 mm.
Ⅲ Sample taking and preparation
1, The sample should be taken according to GB/T 450.
2, 15 mm away from the edge of the sample, cut a sufficient number of samples, to ensure that there are 10 valid data in the vertical and horizontal direction. The specimen should be free of paper defects affecting strength.
The two sides of the sample are straight, the parallelism should be within 0.1mm, and the incision should be neat without any damage. Note: when cutting soft thin paper, the sample can be picked up with a hard paper.
3, Sample size
(1) The width of the sample should be (15+0)mm, if other widths should be indicated in the test report;
(2) The sample should be of sufficient length to ensure that the sample will not touch the sample between the clips. Usually the shortest length of the sample is 250 mm; Laboratory handwritten pages shall be cut in accordance with their standards. The clamping distance during the test should be 180 mm. If other clamping distance lengths are used, it should be indicated in the test report.
ⅣTest steps
1. Instrument calibration and adjustment
Install the instrument according to the instruction and calibrate the force measuring mechanism according to Appendix A. If necessary, the elongation measuring mechanism should also be calibrated. Adjust the loading speed according to 5.2.
Adjust the load of clamps so that the test strip shall neither slide nor be damaged during the test.
The appropriate weight is clamped to the clip and the weight drives the loading indicating device to record its reading. When inspecting the indicating mechanism, the indicating mechanism should not have too much backbump, lag or friction. If the error is greater than 1%, the correction curve should be made.
2, Measuring
The samples were tested under standard atmospheric conditions of temperature and humidity treatment. Check zero and front and back level of measuring mechanism and recording device. Adjust the distance between the upper and lower clamps, and clamp the sample in the clamps to prevent hand contact with the test area between the clamps. A pre-tension of about 98 mN(10g) is applied to the sample so that it is vertically clamped between the two clips. The loading rate of fracture in (20 soil 5)s was calculated by predictive test. The maximum force applied should be recorded from the beginning of the measurement until the specimen breaks. Elongation at break should be recorded when necessary. At least 10 strips of paper and board should be measured in each direction and the results of all 10 strips should be valid. If the clamp is broken within 10 mm, it should be discarded.
ⅤThe results calculated
The results showed that the vertical and horizontal results of paper and cardboard were calculated and represented respectively, and there was no difference in the direction of laboratory hand-copied pages.
According to the standard “GB/T 453-2002 IDT ISO 1924-1:1992 paper and board tensile strength determination (constant speed loading method)” our company developed products DRK101 series electronic tensile testing machine. It has the following characteristics:
1, The transmission mechanism adopts ball screw, the transmission is stable and accurate; Imported servo motor, low noise, accurate control.
2, Touch screen operation display, Chinese and English exchange menu. Real-time display of force-time, force-deformation, force-displacement, etc. The latest software has the function of displaying tensile curve in real time. The instrument has powerful data display, analysis and management capabilities.
3, The use of 24-bit high precision AD converter (resolution up to 1/10,000,000) and high precision weighing sensor, to ensure the speed and accuracy of the instrument force data acquisition.
4,The use of modular thermal printer, easy installation, low fault.
5,Direct measurement results: after the completion of a group of tests, it is convenient to directly display the measurement results and print statistical reports, including mean, standard deviation and coefficient of variation.
6, High degree of automation, the instrument design uses advanced devices at home and abroad, microcomputer for information sensing, data processing and action control, with automatic reset, data memory, overload protection and fault self-diagnosis characteristics.
7, Multi-function, flexible configuration.
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Post time: Nov-03-2021
