Impact test method

An impact test machine is used to determine the impact load resistance of metal materials, also known as impact toughness test. In the impact test, the work consumed to rush the sample is called impact work, and the unit is Joule (J), expressed in Ak. Divide Ak by the cross-sectional area F at the sample notch,It is obtained by obtaining Ak/F=ak, which is joules/cm2 (J/cm2), which is called the material impact value. ak can be used to evaluate the toughness and brittleness of materials, but cannot be used directly in design calculations.
According to the sample shape and breaking method, the impact tester can be divided into bendingImpact testing machine, torsional impact testing machine and tensile impact testing machine. Among them, the pendulum bending impact test machine has a wide application and simple method. The results of the impact test are as follows:In close relationship, the test results obtained with samples of different sizes and shapes cannot be compared with each other. Therefore, all countries stipulate that there are standard samples. In Chinese standards, plum samples and shabi V-shaped notch samples are mainly used. The impact test is very sensitive to the tissue defects of metal materials, and can detect defects and tissue changes caused by the material during smelting and processing processes. When the same sample is subjected to impact test at a temperature from high to low, the impact work (or impact toughness) will beFrom large to small, crystal fractures are from small to large, and plastic deformations are from large to small, which means that the material transitions from a tough state to a brittle state. Usually, the temperature when 50% of the crystal fracture area appears on the fracture is called the toughness-brittle transition temperature or brittle transition temperature.