ASTM D746-04 pdf free.Standard Test Method for Brittleness Temperature of Plastics and Elastomers by Impact.
In establishing the brittleness temperature of a material, it is recommended that the test be started at a temperature at which 50 % failure is expected. Test a minimum of ten specimens at this temperature. If all of the specimens fail, increase the temperature of the bath by 109C and repeat the test using newspecimens. If none of the specimens fail, decrease the bath temperature by 109C and repeat the test using new specimens. If the approx imate bittleness temperature is not known, select the start temperature arbitrarily.
Prior to beginning a test, prepare the bath and bring the apparatus to the desired starting temperature. If the bath is cooled using dry ice, place a suitable amount of powdered dry ice in the insulated tank and slowly add the heat-transfer medium until the tank is flled to a level 30 to 50 mm from the top. If the apparatus is equipped with a liquid nitrogen or CO2 cooling system and automatic temperature control, follow instructions provided by the manufacturer of the ins trument for preparing and operating the bath.
Mount the test specimens firmly in the clamping device. Secure the specimens with a torque wrench. To avoid excessive deformation of the specimens, use a torque suitable for the material being tested.
In comparing two test results for the same material, obtained by different operators using different equipment on different days, those test results are to be judged not equivalent if they differ by more than the R value for the material and condition, (This applies between diferent laboratories or between different equipment within the same laboratory.)
Any judgement in accordance with 13.1.3 and 13.1.4 will have an approximate 95 % (0.95) probability of being correct.
Securing Ball Support- Remove either one of the nuts that fasten the striking bar guide rods to the solenoid armature yoke. Place the small hole of the ball support (Fig.X1.1) over the guide rod and replace and secure the nut.ASTM D746 pdf download.