Abstract
In this paper we describe an experimental study on the tensile characteristics of welded acrylic polyvinyl chloride at low temperature. This study intends to clarify the low temperature characteristics of welded part comparing with those of base material. The results of some measurements on the tensile properties from room temperature down to the neighborhood of -195°C are reported and the appearances of tensile fracture surfaces observed by scanning electron microscope are shown, and the changes in tensile properties under low temperature atmosphere are discussed from a microscopic point of view. Furthermore, notch and load velocity effects on the brittle fracture tendency are also discussed. Material used for this experiment was acrylic polyvinyl chloride (Kydex #7300 type) board of 2 mm in thickness, and welding was carried out by a semi-automatic heat plate welder. Tension tests were carried out by using Autograph IS-2000, and low temperature atmosphere was prepared by dry ice and liquid nitrogen.
Conclusions obtained in this study are summarized as follows;
1) Both welded part and base material of acrylic polyvinyl chloride become brittle at low temperature.
2) Welding joint efficiency of acrylic polyvinyl chloride gradually decreases as temperature becomes low.
3) Notch and load velocity effects are observed both on the base and the welded materials, and low temperature brittleness becomes great when specimen is notched and load velocity is high.
4) Correlations are observed between fracture surfaces and mechanical testing results.
5) Impact energy for tensile fracture of acrylic polyvinyl chloride is very high even at low temperature, but that of welded acrylic polyvinyl chloride becomes very low both at room temperature and low temperature.
