Astm d638-10 pdf free download

I This test method is designed to produce tensile property data for the control and specification of plastic materials. Therefore, it is advisable to refer to that material specification before using this test method. 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.

However, because of the high degree of sensitivity exhibited by many plastics to rate of straining and environmental conditions. 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.

Test speed is determined by the material speciication and an extensometer is used to measure specimen parameters. Due to the viscoelastic nature of plastics, these tests are oten performed with temperature chambers to simulate end-use environments. Modulus needs to be measured within the linear elastic portion, where very little strain exists. Extensometers with high accuracy typically have limited travel and must be removed from the specimen during the test.

Test operators prefer the simplicity and intuitive nature of TW Express. This software allows operators to easily execute tests and MTS consultants are also available to support any of your plastics monitor data or calculated values in runtime views.

Most of the time, additional options are available and necessary to accomplish your more comprehensive test objectives. Type IV specimen is generally used material having a thickness of 7 mm 0. Type II specimen is when direct comparisons are required between materials in different recommended when a material does not break in the narrow section with rigidity cases.

Type V specimen shall be used for limited availability material having a thickness of 4 mm 0. On tube and rod specimens, the location forthe grips shall be as shown in Fig. Tighten thegrips evenly and firmly to the degree necessary to preventslippage of the specimen during the test, but not to the pointwhere the specimen would be crushed. Attach the extension indicator. When modulus is beingdetermined, a Class B-2 or better extensometer is required see5. Make simultaneous measurements of load andstrain and record the data.

It is recommended that thedata collection rate for the test be a minimum of 20 points persecond. This is particularly important for materials having anon linear stress to strain curve.