The ball pressure test is to press the steel ball (R2.5mm) and the ball pressure tester with a total test of 20N±0.2N on the surface of the test sample in a horizontal state and placed in the heating box, and then test it at the specified temperature of the test sample. After 60min+2min/0min, quickly (<10s) intrude the sample into 20℃±5℃ water to cool for 6min, take it out of the water and measure the diameter of the indentation on the surface of the sample within 3min. Thermal deformation resistance at the specified temperature.

1. According to the test requirements, put the ball pressure test device in the heating box for a long enough time to ensure that the ball pressure test device has reached a stable test temperature before the test starts.
2. Place the part under test on the support base so that it is in direct contact with the support base.
3. Place the surface of the part under test in a horizontal position and press the steel ball against the surface (see figure below). The test shall be carried out in a heating box at the temperature specified in the standard.
4. After the test reaches the time specified in the standard, remove the ball from the sample, and after cooling according to the requirements of the standard, measure the diameter of the indentation of the steel ball to determine whether it is qualified or not.