Charpy pendulum impact test on metallic materials أداة الاختبار –

Charpy Pendulum Impact Test for Metallic Materials

The Charpy Pendulum Impact Test is a test used to determine the notch resistance (toughness) of metallic materials. Prepare a metal sample of a certain shape and size (usually 10 × 10 × 55 mm) with a U-shaped or V-shaped notch. It is in a state of a beam simply supported on the testing machine at the Charpy shock, the pendulum being lifted by the testing machine. The hammer makes an impact to break the sample along the notch. The difference in height when the pendulum swings back when broken is used to calculate the energy absorbed by the sample, which is Aku (U-shaped notch) and Akv (V-shaped notch). Impact tests can be carried out at different temperatures. The greater the value of the absorbed energy (joules), the better the toughness of the material and its insensitivity to gaps in the structure or to othervery stress concentration conditions.

1. Application of Charpy impact test:
As a toughness index, it provides a basis for the selection and design development of new materials;
Check and control the quality of metallurgical products;
Supervise the quality of heat treatment technology;
Evaluate the tendency for brittle transformation of materials at different temperatures;
Determine the sensitivity to stress aging;
Sensitivity index to the notch

2. Principle
Place a sample of notch of specified geometric shape between the two supports of the testing machine, the notch being opposite the striking surface , and strike the sample once with a pendulum to measure the absorbed energy of the sample.
Since the impact value of most materials changes with temperature, the test should be carried outkilled at the specified temperature. Including high temperature impact test, low temperature impact test and room temperature impact test.

3. Specimen
The standard size impact sample measures 55 mm in length and 10 × 10 mm in cross section. There is a V-shaped or U-shaped notch in the middle of the length of the sample. GB/T 229 states that if the sample is not sufficient to prepare standard size samples, small size samples with widths of 7.5mm, 5mm and 2.5mm can be used.
　

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