Specific items and tests of the hottest PE pipe in

PE pipe inspection standard specific items and tests

PE pipe inspection standard specific items:

I. aging test:

UV aging test can not fully reconcile production and demand: astmg, iso:2006, gbt16422.3

xenon lamp aging test: astmg155, ISO, gbt16422.2, SAEJ

neutral salt spray detection: gb/t, astmb, gbt2423

alternating salt spray detection: gbt2423

acid salt spray detection: gb/t10125 to avoid extended failure -1997

ozone aging test: GBT

high temperature aging test: gbt2423

low temperature aging test: gbt2423

high and low temperature cycle detection: gb2423

damp heat aging test: gb2423

II. Physical property test:

tensile strength and tensile modulus: astmd638, isor527, din53455, din53457

understanding the response of materials to load is the basis for understanding material properties. By testing the deformation degree (strain) of the material under a certain stress, the designer can predict the application of the material in his working environment

bending strength and bending modulus: astmd790, ISO178, din53452

bending strength is used to measure the ability of materials to resist flexural deformation or to test the rigidity of materials. Different from tensile load, when testing bending, all stresses are loaded in one direction

bending modulus (ratio of stress to strain) is an important index to characterize the bending properties of materials. Compression modulus refers to the ratio of compressive stress to compressive strain within the linear range of the stress-strain curve

wear resistance test: Ge, astmd1044, iso3537, din52347

wear test samples with Taber wear machine, and characterize the wear resistance of materials by calculating the wear amount of samples. The test sample is placed on a rotating turntable with a constant speed of 60rpm (as shown in Figure 4), and a certain weight of grinding wheel is pressed on the test sample (the turntable is manually ground, and turntables with different weights can be obtained). When the turntable reaches the specified number of turns, the test is over. Then weigh the mass of the sample fragments that fall off after wear to characterize the wear resistance index of the material. The wear resistance index is mg/1000 cycles

difference between ASTM and ISO: the thickness of ASTM test sample is 3mm, while that of ISO test sample is 4mm. The different thickness of the sample will lead to different test results. The difference in test results is due to different test methods, not to different material properties. The ISO test method is not only that the test conditions and the size of the sample are different from ASTM, but also that the ISO test sample needs to be processed under the specified processing conditions according to the iso294 standard

impact performance

in standard tests, such as tensile and bending tests, the low sampling rate of energy absorbed by materials is relatively slow, but in practical applications, materials often absorb sudden energy, such as falling objects, strong winds, collapses, high-altitude falls, etc. The purpose of impact testing is to simulate these situations. Notch and non notch impact testing is to characterize the behavior of materials under specified impact stress, so as to characterize the brittleness and toughness of materials. The data of impact test cannot be used as the basis of material design. The specific behavior of materials can be obtained by testing experiments under different conditions, such as changing the size of the notch and the test temperature

impact test is realized on the pendulum cantilever impact instrument. The sample is fixed on the fixture, and a pendulum (impact blade with fixed radius) is released from a fixed height, so that the sample can absorb instantaneous energy. The difference between the height released by the pendulum and the height finally swung back represents the energy absorbed by the fracture of the test spline. The test needs to be carried out at room temperature or at low temperature (to characterize the low-temperature impact toughness of the material). There are different types of test splines and different notch sizes

the result of impact test is not absolute, unless the geometry of the test spline is consistent with the actual final use environment. If the failure rate and failure mode of the two materials are the same, the impact properties of the materials under the two test methods are equal

comparison of impact properties: ASTM and ISO

impact properties are very sensitive to the thickness and molecular orientation of the test specimen. The thickness difference of the specimen used in ASTM and ISO methods may have a great impact on the impact. The thickness changed from 3mm to 4mm, and even the failure mode was changed from plasticity to brittleness through the impact performance of Izod notch by molecular weight and specimen thickness (as shown in Figure 9). However, materials that show brittleness at 3mm, such as mineral and glass filling grades, are not affected. The materials added with impact modifier are not affected by this factor

notch impact strength: astmd256, iso180

notch impact strength has become a standard test to compare the impact toughness of materials. However, the relationship between notch impact test and the actual use environment of products is relatively small. Because changing the notch sensitive material will greatly change the test results. Impact test is mainly used to characterize the sensitivity of materials to notch rather than impact resistance. Notch impact strength test is mainly used to compare the toughness of materials. Notch impact test is of great practical significance for the impact toughness of some products with sharp corners, sharp corners and reinforcing ribs

for the specimen geometry of notchless impact test, the test load is the same as that of notched specimen, except that there is no notch on the test specimen. This test is more accurate than notch impact because it reduces the stress concentration caused by milling notch

impact strength is obtained by dividing the energy absorbed by the sample by the product of the thickness and width of the sample at the notch, and the unit is kj/m2. The difference of ISO test standards reflects the type of specimen and notch. Iso180/1a refers to type 1 specimen and notch a. The size of the sample is 80mm long, 10mm high and 4mm thick. Iso180/1u means that the sample is of type 1, but the fixture is reversed. In the ASTM Test method, the length of the sample is 63.5mm, more importantly, the thickness of the sample is 3.2mm, and the radius and height of the pendulum are consistent with ISO

Vicat softening temperature: astmd1525, iso306, din53460

the purpose of Vicat softening temperature test is to test the rapid softening of materials at that temperature. Plastic in liquid heat transfer medium, under certain load and constant heating rate, the temperature when the sample is pressed into 1mm by 1mm2 pressing head, that is, Vicat softening temperature. Iso306 has two standards: A: the load is 10N; B: The load is 50N, and the heating rate is 50 ° c/h or 120 ° C/h. In ISO, A50 and A1 international have often been used as 120, B50 and B120 standards to measure the national scientific and technological level. The test spline is soaked in the heated oil bath, and the starting heating temperature is from 23 ° C. After 5min, 10N or 50N load is loaded on the test sample. When the sample is pressed into 1 ± 0.01mm by the pressing head, the temperature of the oil bath is VST

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