ASTM D648-2018 pdf free download

ASTM D648-2018 pdf free download.Standard Test Method for Deflection Temperature of Plastics Under Flexural Load in the Edgewise Position
1. Scope
1.1 This test method covers the determination of the tem- perature at which an arbitrary deformation occurs when speci- mens are subjected to an arbitrary set of testing conditions. 1.2 This test method applies to molded and sheet materials available in thicknesses of 3 mm ( 1 ⁄ 8 in.) or greater and which are rigid or semirigid at normal temperature. N OTE 1—Sheet stock less than 3 mm (0.125 in.) but more than 1 mm (0.040 in.) in thickness may be tested by use ofa composite sample having a minimum thickness of 3 mm. The laminae must be of uniform stress distribution. One type of composite specimen has been prepared by cementing the ends of the laminae together and then smoothing the edges with sandpaper. The direction of loading shall be perpendicular to the edges of the individual laminae. 1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.4 Some older machines still use mercury-in-glass ther- mometers. (Warning—Mercury has been designated by many regulatory agencies as a hazardous material that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet (SDS) for additional information. Users should be aware that selling mercury and/or mercury contain- ing products into your state or country may be prohibited by law. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use.N OTE 2—The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. N OTE 3—This standard and ISO 75-1 and ISO 75-2 address the same subject matter, but differ in technical content, and results shall not be compared between the two test methods. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 A bar of rectangular cross section is tested in the edgewise position as a simple beam with the load applied at its center to give maximum fiber stresses of0.455 MPa (66 psi) or 1.82 MPa (264 psi) (Note 4). The specimen is immersed under load in a heat-transfer medium provided with a means of raising the temperature at 2 6 0.2°C/min. The temperature of the medium is measured when the test bar has deflected 0.25 mm (0.010 in.). This temperature is recorded as the deflection temperature under flexural load of the test specimen. N OTE 4—A round robin has been conducted that showed that there is no advantage to using higher loads when measuring deflection temperature of present-day plastics with present-day instruments.
5. Significance and Use
5.1 This test is particularly suited to control and develop- ment work. Data obtained by this test method shall not be used to predict the behavior of plastic materials at elevated tempera- tures except in applications in which the factors of time, temperature, method of loading, and fiber stress are similar to those specified in this test method. The data are not intended for use in design or predicting endurance at elevated tempera- tures. 5.2 For many materials, there may be a specification that requires 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. Refer to Table 1 in Classification D4000, which lists the ASTM material standards that currently exist.