ASTM D638-14 pdf free.Standard Test Method for Tensile Properties of Plastics.
ASTM D638 covers the determination of the tensile properties of unreinforced and reinforced plastics in the form of standard dumbbell-shaped test specimens when tested under defined conditions of pretreatment, temperature, humidity, and testing machine speed.
ASTM D638 is designed to produce tensile property data for the control and specification of plastic materials. These data are also useful for qualitative characterization and for research and development.
4. Significance and Use
4.I This test method is designed to produce tensile property data for the control and specification of plastic materials. These data are also useful for qualitative characterization and for research and development.
4.2 Some material specifications that require the use of this test method, but with some procedural modifications that take
precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table I in Classification D4000 lists the ASTM materials standards that currently exist.
4.3 Tensile properties are known to vary with specimen preparation and with speed and environment of testing Consequently, where precise comparative results are desired these factors must be carefully controlled.
4.4 It is realized that a material cannot be tested without also testing the method of preparation of that material. Hence, when comparative tests of materials per se are desired, exercise great care to ensure that all samples are prepared in exactly the same way, unless the test is to include the effects of sample preparation. Similarly. for referee purposes or comparisons within any given series of specimens, care shall be taken to secure the maximum degree of uniformity in details of preparation, treatment, and handling.
4.5 Tensile properties provide useful data for plastics en
neering design purposes. However, because of the high degree of sensitivity exhibited by many plastics to rate of straining and environmental conditions. data obtained by this test method cannot be considered valid for applications involving load-time scales or environments widely different from those of this test method. In cases of such dissimilarity, no reliable estimation of the limit of usefulness can be made for most plastics. This sensitivity to rate of straining and environment necessitates testing over a broad load-time scale (including impact and creep ) and range of environmental conditions if tensile prop erties are to suffice for engineering design purposes.