Deflection Temperature Under Load DTUL ASTM

The most commonly used are the measurement of the Vicat softening point (ASTM D1525, DIN 53460, ISO 306) and the deflection temperature under load (DTUL, ASTM D648). Both measurements monitor the modulus change with temperature, and determine an endpoint when a macroscopic change can... 

Material selection for elevated temperature applications. The task of evaluating new materials and projecting their performance for specific applications is a challenging one for engineers and designers. Often materials are supplied with short-term test information such as deflection temperature under load (DTUL) (ASTM D693-03a... 

DEFLECTION TEMPERATURE UNDER LOAD (DTUL) (ASTM D648)... 

Yanai et al. (30) demonstrated a definite correlation between data from Accepted ASTM methods and those obtained by TMA. These methods are the deflection temperature under load (DTUL) and the V1CAT softening temperature. The DTUL is determined in the ASTM method by applying a load to the center of a sample that acts as a beam supported at both ends (31I. The Young s modulus of this beam is calculated by... 

The deflection temperature under load (DTUL), also called the heat distortion temperature (HDT) of a plastic is a method to guide or assess its load-bearing capacity at an elevated temperature. Details on the method of testing are given in ASTM D648. Basically, a 1.27-cm (i-in.)-deep plastic test bar is mounted on supports 10.16 cm (4 in.) apart and loaded as a beam (see Fig. 2-21). A bending stress of either 66 psi or 264 psi (455 g Pa or 1,820 g Pa) is applied at the center of the span. The test is conducted in a bath of oil, with the temperature increased at a constant rate of 2 C per minute. The DTUL is the temperature at which the sample attains a deflection of 0.0254 cm (0.010 in.). 

ISO 75 An International Organization for Standardization (ISO) standard test method for determination of heat deflection temperature (HDT) and deflection temperature under load (DTUL). HDT is a relative measure of a materials ability to perform for a short time at elevated temperatures while supporting a load. The test measures the effect of temperature on stiffiiess a standard test specimen is given a defined surface stress and the temperature is raised at a uniform rate. Alternate test methods for HDT and DTUL are DIN 53461 and ASTM D648. 

ASTM D 648 describes a method for determining the heat deflection temperature (HDT) or deflection temperature under load (DTUL). With the trend toward globalization, this method is reflected in and refined by ISO 75. Both tests seek to define the temperature at which a given degree of bending is achieved in a sample placed under a fixed flexural stress. The apparatus used to conduct the test is shown (Figure 1). The working portion of the instrument is immersed in an oil-based fluid, which is used as the heat transfer medium. A specimen is placed in a 3-point bend fixture and the desired stress... 

The deflection of the test bar is continuously observed the temperature at which the deflection reaches 0.32 mm (ISO) or 0.25 mm (ASTM), is reported as deflection temperature under load or heat deflection temperature. Although not mentioned in either test standard, it has become common practice to use the acronym DTUL for ASTM values and HDT for ISO values. Depending upon the applied surface stress, the... 

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