ISO 527-1 and ISO 527-2 standard plastic tensile test
ISO 527-1-2, ASTM D638thisTensile testUsed for testing the basic mechanics performance of the molding material.These characteristic values most for the purpose of comparison.ISO 527-1And (general principles)ISO 527-2Test conditions (moulding and extrusion materials) standard is describedPlastic tensile test.The ISO 527The guiding principle of the standard is in different laboratories, companies and border achieve high reproducibility of test results.
Details about the plastic tensile test, please seeASTM D638Standard.
Goals and property valuesSample typeThe sample sizeEnvironmental conditionsThe precision requirementvideoCompared with other test methodsThe test systemPlastic manual
Goals and features of the ISO 527 standard tensile test value
Determination of a series of characteristic value purpose is to describe the basic mechanics performance of the molding material.These characteristic values most for the purpose of comparison.
Typical property value is:
- Tensile stress: related to sample the original cross-sectional area of tensile load
- Strain:
- The tensile modulus, strain - stress curve slope
- The yield point: in the stress-strain curve slope change to zero point
- Breaking point: stress and strain when the sample is broken
- Poisson's ratio: the transverse normal strain and axial strain is the ratio of the absolute value of
ISO 527-1/2And ASTM D638The standard forTensile testThe test method of definition.Two standard techniques, but does not provide completely comparable test results, because the sample shape, test speed, and the method of the calculation results there are differences in some respects.
In the standard of tensile test, shown in the test results on the sample based on the provisions of the drawing speed.However, in actual use of load acting on the component or structure may be in a wide range of deformation rate range.Due to the viscoelastic polymer, practical use because of the change of strain rate on the mechanical properties of the different from using the standard sample measured results.Based on this reason, the use method of characteristic value of the tensile test for parts design reference value is small, but for the material provides a reliable data basis.
TestXpert III - ISO 527-1 (ASTM D638) standard plastic tensile test
TestXpert III testing softwareIs an ideal solution to meet the requirements of all tests.The software is working closely with material testing industry software users, including many functions to support your daily operation.ISO 527-1/2andASTM D638To define test method of tensile test.Two standard techniques, but does not provide completely comparable test results, because the sample shape, test speed, and the method of the calculation results there are differences in some respects.ZwickRoell provided testXpert III is a preset standard test procedure, ensures to meet standardsISO 527-1andASTM D638Requirements.According to the standardThe ISO 527All the Settings are needed to implement the test has been set up in advance.testXpert中还提供了许多其他详细信息。
The specimen type/shape
ISO standards are defined in the specimen shape and size
Test molding material, the most important purpose is to get a high reproducibility of the data.The need to limit the number of sample types.
- Samples are usually made by the injection molding method.standardISO 527-2The sample is defined asType 1 a;And in the standardThe ISO 3167The sample was definedType A, in 4 mm thickness limitation.In the standardThe ISO 20753The sample was also definedType A1.
- Injection sample presents from the injection port to gradually reduce the location away from the injection port orientation, led to the discontinuous mechanical characteristic curve in the direction of the sample length.Therefore, the sample fracture frequently appeared in the far away from the position of the injection port.
- The most suitable sample gauge length is 75 mm or 50 mm.
- In addition,Type 1 bThe sample can also be used;The sample inThe ISO 3167Is defined asType BIn theThe ISO 20753Is defined asType A2.
- Sample is basically by molding or injection molding of the sheet.Orientation of polymer is usually with the injection of samples are quite different.Different shapes of sample comparability cannot guarantee the result.
- Gage length 50 mm are defined for type 1 b sample, because of its larger radius in parallel to the shorter length.
Used for aging test, the dielectric aging test and climate ageing test sample
- Sample of small cross section to simulate all the aging process and aging begins from the surface of the sample.
- Often only use the maximum tensile stress to evaluate this kind of behavior.Do not need to use the stretch gauge, can use thin and shrinkage "waist" sample.
- The ISO 527provideType CP and the CWFor this purpose;The reference to theImpact tensile standard ISO 8256.
The sample size
- Sample size measurement can lead to a relatively high stress numerical error.When a specimen under tensile load, measurement error will impact on the sample of stress results present linear.When a specimen under bending load, sample thickness measurement error has a secondary effect.
- In addition to read the accuracy of the measuring device, the size of the contact element and form and load at the surface measurement has a great influence on the measurement of force.
- In addition, the cross section of specimen is often not ideal rectangular form.This may be due to mechanical processing or sag and the secondary injection sample due to draft Angle error.
- A lot of test standard referenceThe ISO 16012And/orASTM D5947Develop measurement requirements and methods.Sometimes, each contains additional test standard.
- For example, often use a caliper to measure length is greater than 10 mm of hard plastic.Due to the measurement of surface pressure can't detect, even if the resolution of the caliper is very high, test precision is low.
- Sample thickness and width of the general use of ratchet micrometer to measure.The contact surface is 6.35 mm diameter circle plane.Ratchet limits measuring force for 5-15 N.
- In the automatic system, thickness and width by cross section measuring equipment.The measuring equipment used in measuring the size of the process of four digital measuring sensor at a certain through measuring force sensor foot support sample.
- For soft plastics and film to strictly comply with the requirements of the measuring force.In order to meet the requirements, be sure to use a fixed number of load support thickness measuring instrument.
Temperature control device and environmental conditions
- Comply with the provisions of the regulation and environmental conditions is the temperature and humidity for the comparison of test results is critical.
- Specification relating to the mediation length, usually refer to the material standard plastic preparation test section.In addition, used for molding material test sample must be kept inThe standard environmentThe temperature and humidity conditions (standard) placed at least16 hoursTo test.
- See the standard for test environmentThe ISO 291orASTM D1349Defined in the standard environment.
Test environment: 23 + 2 ° C, 50 plus or minus 10% r.F.
Subtropical environment: 27 + 2 ° C, 65 plus or minus 10% r.F. - Tolerances conform to the requirement of accuracy of the secondary.The tolerance level precision in half.
- Room temperature usually cited a relatively wide temperature range, between 18 ° C and 28 ° C.
- Under the condition of high temperature or low temperature test is possible, you can define various test requirements.
Testing machine precision
Machine test measure the two basic value: force and elongation.As part of the periodical calibration, based on the national institute of standards and measurement equipment, data have shown that these measurements are within the scope of the definition of measurement can reach the accuracy of test standard.
Test force measurement (ISO 7500-1, ASTM E4)
Most of the test standards of numerical measurement accuracy of 1%.This requirement in ISO standard is defined as the precision of grade 1.Now most of the modern testing machine precision has reached the level 1, or some precision up to 0.5, its error in half.So the decisive factor is to achieve the specific testing machine precision level measurement range.A variety of ZwickRoell tester in the range of the measurement range 1\1000 precision has reached the level 1.This means that you can use the same test set, need not reset the instrument can measure many material's modulus and tensile stress value.
Test force measurement (ISO 7500-1, ASTM E4)
Most of the testing standard test data measurement accuracy of 1%.This requirement in ISO standard is defined as the precision of grade 1.Now most of the modern testing machine precision has reached the level 1, or some precision up to 0.5, its error in half.So the decisive factor is to achieve the specific testing machine precision level measurement range.A variety of ZwickRoell tester in the range of the measurement range 1\1000 precision has reached the level 1.This means that you can use the same test set, need not reset the instrument can measure many material's modulus and tensile stress value.
Elongation measurement (ISO 9513, ASTM E83)
In addition to the provisions of the relative error percentage (display), the level of measuring elongation definition also includes an absolute error, will occur when measuring small elongation.
ISO and ASTM standard on this difference is very big.
- Tolerance reference elongation of ISO, ASTM direct reference should be variable.
- In addition, for the regulation of small strain than in the ISO standard strictly in the ASTM standard.
- The gage length can sometimes lead to different results are quite different, especially when measuring small elongation.
When measuring the tensile modulus of special considerations
- As shown in the following form, in ISO standard grade 1 precision corresponds to the tensile modulus and strain range is + / - 3 (including m precision requirements.This means that when measuring the modulus of deviation can be achieved from start to finish including 6 m.This will cause relatively large measurement error.
- In order to solve this problem,ISO 527-1Increased the tensile modulus measurement of additional requirements.This additional requirement for measuring the tensile modulus modulus from start to the end of the modulus of accuracy is 1%.
