Impact test is in accordance with the standard requirements, the steel through the machining of standard specimens, the specimen constant temperature to the specified temperature, in the simple support beam impact test machine through the pendulum broken specimen, through the pendulum broken specimen loss of energy to assess the impact of the material absorbed work.
Impact testing machine is fixed in the column by the free rotation of the beam on the basis of the addition of a pendulum, so that the pendulum can be free to the beam as the centre of the circle swing. A circular indicator disc indicates the amplitude of the pendulum swing.
The specific test procedure is as follows:
Firstly, the pendulum is lifted up to a fixed angle and locked, and after the pendulum is lifted up, the pointer of the indicator disc is manually reset to zero;
Through the release of the pendulum mechanism to release the pendulum so that the pendulum empty hit, the indicator disc pointer with the pendulum swing and rotation, in the pendulum swing up the highest place to stop, to obtain the empty pendulum lifting angle;
Raise the pendulum again, return the pointer to zero, quickly place the sample specimen in the specimen support and release the pendulum, record the pendulum lifting angle after breaking the specimen;
Through the empty pendulum and interrupt the specimen twice the pendulum lifting angle difference calculated by the pendulum broken specimen loss of energy that is the specimen of the impact absorbed work.
Modern impact testing machine through the servo motor and sensors can automatically control the pendulum swing, automatic measurement of the pendulum lifting angle, automatic calculation of the impact absorbed work in order to obtain more accurate test data.
Different from the tensile test of slowly applied tension, impact test is in the instantaneous application of force to the specimen to obtain the mechanical properties of the material in the impact, mainly reflects the use of steel in the existence of a large amount of impulse under the use of conditions, such as punching, piling and other operations.
Another direction of impact testing is to detect the brittle transition temperature of the material. Steel becomes soft at high temperatures, so steel plants are prone to collapse due to loss of support at high temperatures from fire.
And in a certain low temperature steel will lose toughness, become easy to break, often room temperature is very tough steel in the brittle transition temperature below the use of easily due to impact and breakage.