Test method and procedure of impact test

I. Test method:

1, according to the shape of the sample and the breaking way, the impact testing machine can be divided into three kinds: bending impact testing machine, torsional impact testing machine and tensile impact testing machine. Among them, the application method of pendulum type bending impact testing machine is simple.

2, impact sample: impact test results are closely related to the shape of the sample, with different sizes and shapes of the sample obtained test results can not be compared with each other. Therefore, each country has a standard sample. In the Chinese standard, Meyner's sample and Charpy's V-notched sample are mainly used.

3. Application: Impact test is very sensitive to the structure defects of metal materials, and can detect the defects and structure changes generated in the smelting and processing process of materials. When the same sample is subjected to impact test from high to low temperature, impact energy (or impact toughness) will change from large to small, crystalline fracture from less to more, and plastic deformation from large to small, which indicates that the material transitions from toughness state to brittle state. Usually, the temperature when 50% crystalline fracture area appears on the fracture is called toughness - brittle transition temperature or brittle transition temperature.

Ii. Experimental steps:

1, take the pendulum: press the pendulum button, through the relay and clutch, contactor action, pendulum lifted to a higher position, touch the micro switch, motor stop, other electrical circuit reset, safety pin out.

2. Return the pin: press the return pin button to return the insurance pin.

3, impact: press the impact button, the electromagnet work, achieve swing impact.

4, put the pendulum: press the lower pendulum button, the end of the test work, put down.