Deflection Temperature Bath
CNS-2229, 4393, ASTM-D648
After placing the specimen on the two supporting racks, inside the bath, add the load post and heat up at a rate of 2°C/min. When the central part of the specimen falls down for a given depth ( plastic at 0.26 mm and ebonite at 0.25~0.33 mm ), the actual temperature required is the deflective one, the information you need. You also have to test the cross-breaking strength of the specimen at the permanent temperature ( ebonite at 23°C )